CN112737069A

CN112737069A - AC/DC charger

Info

Publication number: CN112737069A
Application number: CN202110114404.3A
Authority: CN
Inventors: 胡炎申
Original assignee: Moso Power Supply Technology Co ltd
Current assignee: Moso Power Supply Technology Co ltd
Priority date: 2021-01-27
Filing date: 2021-01-27
Publication date: 2021-04-30

Abstract

The present application relates to an AC/DC charger. The AC/DC charger includes a PFC main converter, a DC/DC auxiliary converter, a PFC controller and a DC/DC controller; the PFC main converter includes a main output terminal and a DC output terminal, and the DC output terminal and the DC/DC auxiliary terminal The auxiliary input end of the converter is connected, and the main output end is connected in series with the auxiliary output end of the DC/DC auxiliary converter to form a total output end; the control end of the PFC controller is connected with the PFC main converter, and the DC/DC controller includes a voltage control loop and the current control loop; the output end of the voltage control loop and the output end of the current control loop are respectively connected with the control end of the DC/DC controller, and the control end of the DC/DC controller is connected with the DC/DC auxiliary converter. The PFC controller and the DC/DC controller are used to control the output voltage of the PFC main converter and the DC/DC auxiliary converter, so that the total output terminal outputs lower ripple and improves the conversion efficiency.

Description

AC/DC charger

Technical Field

The present disclosure relates to circuit technologies, and particularly to an Alternating Current/Direct Current (AC/DC) charger.

Background

The AC/DC charger is widely applied to various chargers such as mobile phone chargers, PD chargers, electric forklift chargers, battery car chargers, unmanned aerial vehicle chargers, robot chargers and the like.

Generally, an AC/DC charger includes both single-stage and multi-stage configurations. The single-stage AC/DC charger cannot give consideration to both input high power factor and output low ripple, so that a two-stage AC/DC cascade structure is widely used in small-probability chargers and industrial equipment chargers in the industry, the two-stage AC/DC charger can realize high power factor and reduce output ripple voltage or current, but the AC input can obtain total output only after two-stage full power conversion, the conversion efficiency is the multiplication of the conversion efficiency of two converters, more power consumption can be inevitably generated, and the whole conversion efficiency is low.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present application aims to provide an AC/DC charger, which is aimed at solving the problem that the conversion efficiency is high and the output ripple is low.

The embodiment of the application provides an AC/DC charger, characterized by, include: the power factor correction PFC system comprises a power factor correction PFC main converter, a DC/DC auxiliary converter, a PFC controller and a DC/DC controller;

the PFC main converter comprises a main output end and a direct current output end, the direct current output end is connected with an auxiliary input end of the DC/DC auxiliary converter, and the main output end and the auxiliary output end of the DC/DC auxiliary converter are connected in series to form a main output end;

the control end of the PFC controller is connected with the PFC main converter, and the DC/DC controller comprises a voltage control loop and a current control loop; the output end of the voltage control loop and the output end of the current control loop are respectively connected with the control end of the DC/DC controller, and the control end of the DC/DC controller is connected with the DC/DC auxiliary converter;

the PFC main converter outputs a main output voltage through the main output end; the PFC main converter transmits the output direct-current output voltage to an auxiliary input end of the DC/DC auxiliary converter through the direct-current output end; the DC/DC auxiliary converter processes the direct-current output voltage to obtain an auxiliary output voltage, the phase of the ripple of the auxiliary output voltage is opposite to that of the ripple of the main output voltage, and the auxiliary output voltage is output through the auxiliary output end;

the main output end receives the main output voltage and the auxiliary output voltage to form a main output voltage and an output total current; the PFC controller samples a first feedback voltage, and the input voltage of the PFC main converter is controlled to be the same as the input current frequency and the phase by utilizing the first feedback voltage; the voltage control loop samples a second feedback voltage, and the second feedback voltage is utilized to control the phase of a ripple of an auxiliary output voltage output by an auxiliary output end of the DC/DC auxiliary converter to be opposite to the phase of a ripple of the main output voltage; the current control loop samples the total current and controls the DC/DC auxiliary converter by using the total current;

the first feedback voltage comprises one of the main output voltage and the auxiliary output voltage, and the second feedback voltage comprises the total output voltage.

In one possible embodiment, the PFC main converter further comprises a power conversion unit, a main power switch tube and a voltage conversion unit,

the main power switch tube is connected between the output end of the power conversion unit and the input end of the voltage conversion unit, the control end of the main power switch tube is connected with the control end of the PFC controller, and the output end of the voltage conversion unit is connected with the main output end and the direct current output end;

the PFC controller controls the on and off of the main power switch tube;

under the condition that the main power switch tube is conducted, the power conversion unit provides electric energy for the voltage conversion unit, and the voltage conversion unit stores the electric energy;

under the condition that the main power switch tube is cut off, the power conversion unit stops providing electric energy for the voltage conversion unit, and the voltage conversion unit releases the electric energy.

In one possible embodiment, the voltage conversion unit comprises a main winding and an auxiliary winding;

one end of the main winding is connected with one end of the main power switch tube, and the other end of the main winding is connected with the main output end; one end of the auxiliary winding is connected with one end of the main power switch tube, and the other end of the auxiliary winding is connected with the auxiliary output end;

the voltage conversion unit outputs the main output voltage to the main output end through the main winding; the voltage conversion unit outputs the direct current output voltage to the direct current output end through the auxiliary winding.

In one possible embodiment, the PFC controller includes a sampling unit and a conditioning feedback unit;

the output end of the sampling unit is connected with the input end of the conditioning feedback unit, and the output end of the conditioning feedback unit is connected with the control end of the main power switch tube;

the sampling unit is used for: sampling the first feedback voltage; the conditioning feedback unit is used for: generating a first switching tube driving signal based on the first feedback voltage; the first switch tube driving signal is used for controlling the main power switch tube.

In one possible implementation, the sampling unit includes a first sampling terminal, a second sampling terminal, and a third sampling terminal; the conditioning feedback unit comprises: the circuit comprises a first comparator, a second comparator, a third comparator, a first reference voltage source, a first sawtooth wave signal source and a trigger;

the output end of the first reference voltage source is connected with the positive input end of the first comparator, and the first sampling end is connected with the negative input end of the first comparator; the output end of the first comparator is connected with the positive input end of the second comparator, and the negative input end of the second comparator is connected with the second sampling end; the output end of the second comparator is connected with the positive input end of the third comparator, the first sawtooth wave signal source is connected with the reverse input end of the third comparator, the output end of the third comparator is connected with the first input end of the trigger, the third sampling end is connected with the second input end of the trigger, and the output end of the trigger is connected with the control end of the PFC controller;

the first comparator receives a first feedback voltage from the first sampling end and a first reference voltage signal from the first reference voltage source, and compares the first feedback voltage with the first reference voltage to form a first voltage error signal;

the second comparator receives a switching tube voltage signal from the second sampling end and a first voltage error signal from the first comparator, and compares the first voltage error signal with the switching tube voltage signal to obtain a control signal of the main power switching tube, wherein the switching tube voltage signal is obtained by converting a current signal of the main power switching tube;

the third comparator receives a current control signal from the second comparator and a first sawtooth wave signal from the first sawtooth wave signal source, and compares the control signal with the sawtooth wave signal to obtain a stop pulse signal; the third sampling end samples the electric energy of the voltage conversion unit to form a starting pulse signal;

the trigger receives the stop pulse signal and the start pulse signal, and generates the first switch driving signal based on the start pulse signal and the stop pulse signal, wherein the first switch driving signal is used for controlling the on and off of the main power switch tube.

In one possible embodiment, the DC/DC auxiliary converter includes an auxiliary power switching tube, an inductor, and a rectifier diode;

one end of the auxiliary power switch tube is connected with one pole of an auxiliary input end of the DC/DC auxiliary converter, the other end of the auxiliary power switch tube is connected with one end of the inductor, the other end of the inductor is connected with one pole of the auxiliary output end, one end of the rectifier diode is connected between the other end of the auxiliary power switch tube and one end of the inductor, and the other end of the rectifier diode is connected between the other pole of the auxiliary input end of the DC/DC auxiliary converter and the other pole of the auxiliary output end;

under the condition that the auxiliary power switch tube is conducted, the rectifier diode is cut off, the auxiliary input end of the DC/DC auxiliary converter receives the direct-current output voltage and provides electric energy for the inductor, and the inductor stores the electric energy;

and under the condition that the auxiliary power switch tube is cut off, the rectifier diode is conducted, the inductor, the rectifier diode and the auxiliary output end form a current loop, the inductor releases electric energy to provide electric energy for the auxiliary output end, and the auxiliary output end outputs the auxiliary output voltage.

In a possible implementation, the DC/DC controller includes a fourth comparator, a fifth comparator, a sixth comparator, a current reference source, a second reference voltage source, a second sawtooth signal source, a current sampling terminal, a voltage sampling terminal, and a logical or circuit, the fourth comparator, the fifth comparator, the current reference source, and the current sampling terminal form the current feedback loop, and the sixth comparator, the fifth comparator, and the second reference voltage source form the voltage feedback loop;

the positive input end of the fourth comparator is connected with the output end of the current reference source, the negative input end of the fourth comparator is connected with the current sampling end, and the output end of the fourth comparator is connected with the first input end of the logic OR circuit; a positive input end of the sixth comparator is connected with an output end of the second reference voltage source, a negative input end of the sixth comparator is connected with a voltage sampling end, and an output end of the sixth comparator is connected with a second input end of the logic or circuit; the output end of the logic or circuit is connected with the positive input end of the fifth comparator, the negative input end of the fifth comparator is connected with the output end of the second sawtooth wave signal source, and the output end of the fifth comparator is connected with the control end of the DC/DC controller;

the fourth comparator receives a current feedback signal from the current sampling end and a current reference signal from the current reference source, and after the current reference signal and the current feedback signal are compared, a current error signal is formed;

the sixth comparator receives a second feedback voltage from the voltage sampling terminal and a second reference voltage signal from the second reference voltage source, compares the second feedback voltage with the second reference voltage signal, and forms a second voltage error signal;

and the fifth comparator receives the current error signal or the second voltage error signal and a sawtooth wave signal from the sawtooth wave signal source, compares the sawtooth wave signal with the current error signal or the second voltage error signal, and forms a second switch tube driving signal, and the second switch tube driving signal is used for controlling the connection and disconnection of the auxiliary power switch.

In one possible implementation, the logic or circuit includes a first diode and a second diode;

the anode of the first diode is connected with the output end of the logic OR circuit, and the cathode of the first diode is connected with the first input end of the logic OR circuit;

the anode of the second diode is connected between the anode of the first diode and the output end of the logic or circuit, and the cathode of the second diode is connected with the second input end of the logic or circuit.

In one possible embodiment, the voltage stress of the DC/DC auxiliary converter is smaller than a first threshold value and the current stress of the DC/DC auxiliary converter is smaller than a second threshold value.

In one possible embodiment, the PFC controller includes a first communication unit, and the DC/DC controller includes a second communication unit, and the first communication unit establishes a communication connection with the second communication unit.

In one possible embodiment, the PFC main converter comprises one of a flyback converter, a boost converter, a buck-boost converter, a buck converter, and a forward converter;

the DC/DC auxiliary converter comprises one of a flyback converter, a boost converter, a buck-boost converter, a Cuck converter, a forward converter, a bridge converter, a push-pull converter, a single-ended primary inductance type converter and an LLC resonant converter.

In one possible embodiment, the control mode of the PFC controller includes: current critical conduction mode, discontinuous conduction mode, and critical conduction mode.

In one possible embodiment, the PFC controller is integrated with the DC/DC controller into one or more analog chips.

In the embodiment of the application, the main output voltage output by the PFC main converter and the auxiliary output voltage output by the DC/DC auxiliary converter form a total output voltage, and only a part of output power is converted by two stages, so that the conversion efficiency of the AC/DC charger is improved. The PFC controller samples and feeds back the main output voltage or the total output voltage, and controls the input current and the input voltage of the PFC main converter to be sine waves with the same frequency and the same phase while realizing the closed-loop control of the main output voltage or the total output voltage so as to achieve power factor correction and higher power factor and realize zero pollution to a power grid. The DC/DC controller samples and feeds back the second feedback voltage, the second feedback voltage is controlled in a closed loop mode according to the change condition of the second feedback voltage, the second feedback voltage is controlled in a closed loop mode, and meanwhile ripple waves output by the main output voltage and the auxiliary output voltage are indirectly controlled to be superposed in an inverted mode to be offset, and therefore lower ripple waves of the total output voltage are achieved.

Drawings

Fig. 1 is a schematic structural diagram of an AC/DC charger according to an embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of another AC/DC charger provided in the embodiment of the present application;

FIG. 3 is a schematic structural diagram of another AC/DC charger provided in the embodiments of the present application;

FIG. 4 is a schematic structural diagram of another AC/DC charger provided in the embodiments of the present application;

fig. 5 is a schematic structural diagram of a main buck PFC converter according to an embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of a main boost PFC converter according to an embodiment of the present disclosure;

fig. 7 is a schematic structural diagram of a buck-boost PFC main converter according to an embodiment of the present disclosure;

fig. 8 is a schematic structural diagram of a boost DC/DC auxiliary converter according to an embodiment of the present disclosure;

fig. 9 is a schematic structural diagram of a buck-boost DC/DC auxiliary converter according to an embodiment of the present disclosure;

fig. 10 is a schematic structural diagram of a negative voltage step-down DC/DC auxiliary converter according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of a flyback DC/DC auxiliary converter provided in an embodiment of the present application.

Description of reference numerals:

the main PFC converter comprises a main PFC converter 10, a power conversion unit 11, a voltage conversion unit 12, a main winding 121, an auxiliary winding 122, an auxiliary DC/DC converter 20, a PFC controller 30, a DC/DC controller 40, an alternating current power supply 50, a storage battery 60,

input ports

1 and 2 of the main PFC converter,

main output ports

3 and 4, direct

current output ports

5 and 6 and

auxiliary output ports

7 and 8.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

The terms "first," "second," and the like in the description and claims of the present application and in the above-described drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

Referring to fig. 1, fig. 1 is a schematic structural diagram of an AC/DC charger according to an embodiment of the present disclosure. As shown in fig. 1, the AC/DC charger includes a Power Factor Correction (PFC) main converter 10, a direct current (DC/DC) auxiliary converter 20, a PFC controller 30, and a DC/DC controller 40.

The PFC main converter 10 includes a main output terminal and a DC output terminal, the DC output terminal is connected to an auxiliary input terminal of the DC/DC auxiliary converter 20, and the main output terminal and the auxiliary output terminal of the DC/DC auxiliary converter 20 are connected in series to form a total output terminal.

The control terminal of the PFC controller 30 is connected to the PFC main converter 10, and the DC/DC controller 40 includes a voltage control loop 41 and a current control loop 42. An output terminal of the voltage control loop 41 and an output terminal of the current control loop 42 are connected to a control terminal of the DC/DC controller 40, respectively, and a control terminal of the DC/DC controller 40 is connected to the DC/DC auxiliary converter 20.

The PFC main converter 10 outputs a main output voltage Vo1 through a main output terminal, and the PFC main converter 10 transmits an output DC output voltage to an auxiliary input terminal of the DC/DC auxiliary converter 20 through a DC output terminal. The DC/DC auxiliary converter 20 processes the DC output voltage to obtain an auxiliary output voltage Vo2, and the auxiliary output voltage Vo2 is output through an auxiliary output terminal with a ripple of the auxiliary output voltage Vo2 having a phase opposite to that of the main output voltage Vo 1.

The total output end receives the main output voltage Vo1 and the auxiliary output voltage Vo2 to form a total output voltage Vo and an output total current Io. The PFC controller 30 samples the first feedback voltage, and controls the input voltage of the PFC main converter 10 to have the same frequency and the same phase as the input current using the first feedback voltage. The voltage control loop 41 samples the second feedback voltage, and controls the ripple of the auxiliary output voltage Vo2 output from the auxiliary output terminal of the DC/DC auxiliary converter 20 to be opposite in phase to the ripple of the main output voltage Vo1 using the second feedback voltage. The current control loop 42 samples the total current Io and controls the DC/DC auxiliary converter 20 using the total current Io.

The first feedback voltage includes one of the main output voltage Vo1 and the auxiliary output voltage Vo2, and the second feedback voltage includes the total output voltage Vo.

Specifically, an input end of the PFC main converter 10 is connected to an output end of an ac power supply 50, and the ac power supply 50 provides ac power for the PFC main converter 10. The PFC main converter 10 performs power conversion and voltage conversion on the ac power, outputs a main output voltage Vo1 through a main output terminal and a DC voltage through a DC output terminal, transmits the main output voltage Vo1 to a main output terminal, and outputs the DC output voltage to an auxiliary input terminal of the DC/DC auxiliary converter 20. The DC/DC auxiliary converter 20 receives the DC output voltage, converts the DC output voltage to obtain an auxiliary output voltage Vo2, and transmits the auxiliary output voltage Vo2 to the main output terminal through the auxiliary output terminal of the DC/DC auxiliary converter 20. The main output terminal receives the main output voltage Vo1 and the auxiliary output voltage Vo2 to form a main output voltage Vo for charging the battery 60.

A control terminal of the PFC controller 30 is connected to the PFC main converter 10, and an input terminal of the PFC controller 30 may be connected to a main output terminal or a main output terminal to sample a first feedback voltage, and control the PFC main converter 10 based on the first feedback voltage, the PFC main converter 10 and the PFC controller 30 forming a first feedback loop. A control terminal of the DC/DC controller 40 is connected to the DC/DC auxiliary converter 20, and an input terminal of the DC/DC controller 40 may be connected to the main output terminal, the auxiliary output terminal, or the main output terminal to sample a second feedback voltage based on which the DC/DC auxiliary converter 20 is controlled, the DC/DC auxiliary converter 20 and the DC/DC controller 40 forming a second feedback loop.

It will be appreciated that the total output is formed by the main and auxiliary outputs in series, so that the total output voltage Vo is the sum of the main output voltage Vo1 and the auxiliary output voltage Vo 2. Because the power frequency ripple is the inherent characteristics of the main output voltage Vo1 and the auxiliary output voltage Vo2, the phase of the power frequency ripple of the auxiliary output voltage Vo2 output by the DC/DC auxiliary converter 20 controlled by the DC/DC controller 40 is opposite to the phase of the power frequency ripple of the main output voltage Vo1, so that the power frequency ripple of the main output voltage Vo1 and the power frequency ripple of the auxiliary output voltage Vo2 are superposed and then mutually offset, and the total output voltage Vo has lower ripple.

The first feedback voltage includes one of the main output voltage Vo1 and the auxiliary output voltage Vo2, and the PFC controller 30 may selectively sample and feedback the main output voltage Vo1 or the auxiliary output voltage Vo2 through an electronically gated switch. The normal charging process of the battery 60 includes a constant-current charging phase and a constant-voltage charging phase. In the embodiment of the present application, the DC/DC controller may enable one of the voltage control loop 41 and the current control loop 42 through one logic or circuit.

In the constant current charging phase, logic or circuit in the DC/DC controller enables the current control loop 42, and the DC/DC controller 40 samples the total current Io and controls the output current of the DC/DC auxiliary converter 20 according to the variation condition of the total current Io. Because the total output end is formed by connecting the main output end and the auxiliary output end in series, the current of the main output end is equal to that of the auxiliary output end. The output current of the DC/DC auxiliary converter 20 is controlled by the DC/DC controller 40, so as to control the total current Io, so that the total current Io is constant, that is, the charging current of the storage battery 60 is controlled to be a constant value, and the closed-loop control of the total current Io is realized. In the constant-current charging stage, the electronic gating switch in the PFC controller 30 selects the auxiliary output voltage Vo2, that is, the PFC controller 30 samples the auxiliary output voltage Vo2, controls the magnitude of the DC output voltage output by the PFC main converter 10 based on the auxiliary output voltage Vo2 to be sufficient, and indirectly controls the DC/DC auxiliary converter through a feedback loop, so that the magnitude of the auxiliary output voltage is a constant value. The PFC controller 30 controls the input voltage of the PFC main converter 10 to have the same frequency and the same phase as the input current while realizing the closed-loop control of the auxiliary output voltage Vo2, so as to achieve the power factor dumpling and a higher power factor.

Correspondingly, in the constant-voltage charging stage, the electronic gating switch in the PFC controller 30 selects the main output voltage Vo1, that is, the PFC controller 30 samples the main output voltage Vo1 and controls the main output voltage Vo1 output by the PFC main converter 10 according to the variation condition of the main output voltage Vo1, so that the input voltage of the PFC main converter 10 is controlled to have the same frequency and the same phase as the input current while the main output voltage Vo1 is controlled in a closed loop manner, so as to achieve a power factor dumpling and a higher power factor. The logic or circuit in the DC/DC controller 40 enables the current control loop 42, and the DC/DC controller 40 samples the total output voltage Vo and controls the auxiliary output voltage Vo2 of the output of the DC/DC auxiliary converter 20 according to the variation condition of the total output voltage Vo, thereby indirectly controlling the total output voltage so that the total output voltage is constant, i.e., the magnitude of the charging voltage of the secondary battery 60 is controlled to be a constant value. Thereby indirectly controlling the output ripple of the main output voltage Vo1 and the output ripple of the auxiliary output voltage Vo2 to be in anti-phase.

In the embodiment of the application, the main output voltage Vo1 is greater than the auxiliary output voltage Vo2, the PFC main converter 10 provides most of the power for the battery 60, the DC/DC auxiliary converter 20 provides a small part of the output power for the battery 60, the large part of the output power is subjected to single-stage power conversion, and only the small part of the output power is subjected to two-stage power conversion, so that the overall power conversion efficiency is improved.

Specifically, let us assume that the conversion efficiency of the PFC main converter 10 is η_PFCThe conversion efficiency of the DC/DC auxiliary converter 20 is eta_DC/DC，P_PFC、P_DC/DC、P_outRespectively, the output power of the PFC main converter 10, the output power of the DC/DC auxiliary converter 20, and the overall output power, the overall efficiency is:

let P_DC/DC＝10％×P_outAnd then:

is additionally provided with eta_DC/DC90%, the overall conversion efficiency η_total＝98.9％×η_PFC。

As can be seen from the above, if the output power ratio of the DC/DC auxiliary converter 20 is 10%, even if the conversion efficiency of the DC/DC auxiliary converter 20 is as low as 90%, the overall conversion efficiency is close to 99% of the conversion efficiency of the single-stage converter, and compared with the conventional two-stage converter, the conversion efficiency is higher and lower in power loss.

In the embodiment of the present application, the PFC controller 30 controls the input voltage of the PFC main converter 10 to have the same frequency and the same phase as the input current, so as to achieve a power factor of dumpling and a higher power factor, and achieve zero pollution to the power grid. Ripples output by the main output voltage Vo1 and the auxiliary output voltage Vo2 are indirectly controlled by the DC/DC controller 40 to be in opposite phases and superposed to be mutually offset, and lower ripples of the total output voltage Vo are realized. Meanwhile, in the process of charging the storage battery, most output power is subjected to single-stage power conversion, and only a small part of power is subjected to two-stage power conversion, so that the overall power conversion efficiency is improved.

In a possible implementation manner, please refer to fig. 2, and fig. 2 is a schematic structural diagram of another AC/DC charger provided in an embodiment of the present application. As shown in fig. 2, the PFC main converter 10 further includes a power conversion unit 11, a main power switch Q1, and a voltage conversion unit 12.

The main power switch Q1 is connected between the power conversion unit 11 and the voltage conversion unit 12, the control end of the main power switch Q1 is connected with the control end of the PFC controller 30, and the output end of the voltage conversion unit 12 is connected with the main output end and the dc output end.

Specifically, the PFC controller 30 samples the main output voltage Vo1 or the total output voltage Vo, constituting a first feedback signal. The PFC controller 30 generates a first switching tube driving signal based on the first feedback signal, and transmits the generated first switching tube driving signal to the control terminal of the main power switching tube Q1 through the control terminal of the PFC controller 30 to control the on and off of the main power switching tube Q1.

When the main power switching tube Q1 is turned on, the power conversion unit 11 receives ac power from an ac power supply, converts the ac power to supply electric power to the voltage conversion unit 12, and the voltage conversion unit 12 stores the electric power.

When the main power switch Q1 is turned off, the connection between the power conversion unit 11 and the voltage conversion unit 12 is disconnected, the power conversion unit 11 stops supplying the electric power to the voltage conversion unit 12, and the voltage conversion unit 12 discharges the electric power.

In the embodiment of the present application, the PFC controller 30 controls the on/off of the main power switch Q1 to realize the closed-loop control of the main output voltage Vo1 or the total output voltage Vo, and at the same time, the conventional control method, such as the Discontinuous Conduction Mode (DCM), the Critical Conduction Mode (CRM), or the Continuous Conduction Mode (CCM) with a multiplier, makes the envelope waveform of the input current follow the power frequency sine wave of the input voltage to become an interrupted, Critical, or Continuous high-frequency current, so as to eliminate the distortion and the phase change of the current waveform caused by the energy storage of the capacitive element and the inductive element in the conventional circuit without the power factor correction function, and makes the input current and the input voltage have the same frequency and the same phase after being filtered by the input Electromagnetic Interference (EMI) filter, realize power factor correction and improve the power factor.

In one possible embodiment, referring to fig. 2, the voltage converting unit 12 includes a main winding 121 and an auxiliary winding 122.

One end of the main winding 121 is connected to one end of the main power switching tube Q1, and the other end of the main winding 121 is connected to the main output terminal; one end of the auxiliary winding 122 is connected to one end of the main power switching transistor Q1, and the other end of the auxiliary winding 122 is connected to the auxiliary output terminal;

the voltage conversion means 12 outputs the main output voltage Vo1 to the main output terminal through the main winding 121; the voltage conversion unit 12 outputs the dc output voltage Vo3 to the dc output terminal through the auxiliary winding 122.

The voltage conversion unit 12 may be a double winding type transformer having a main winding 121 and an auxiliary winding 122 or a double winding inductor L1.

The resistance of the main winding 121 is smaller than that of the auxiliary winding 122, so that under the same current, the voltage of the main winding 121 is greater than that of the auxiliary winding 122, that is, the main output voltage Vo1 is greater than the auxiliary output voltage Vo2, and the output power of the main output terminal is greater than that of the auxiliary output terminal. Therefore, the conversion efficiency can be improved better.

In one possible implementation, referring to fig. 3, the PFC controller 30 includes a first sampling unit 31 and a first conditioning feedback unit 32.

The output end of the first sampling unit 31 is connected to the input end of the first conditioning feedback unit 32, and the output end of the first conditioning feedback unit 32 is connected to the control end of the main power switch Q1. The first sampling unit 31 is configured to: sampling the first feedback voltage; the first conditioning feedback unit 32 is configured to: generating a first switch driving signal based on the first feedback voltage; the first switch driving signal is used to control the on/off of the main power switch Q1.

Specifically, the first feedback voltage may include one of the main output voltage Vo1 and the total output voltage Vo, and the input terminal of the first sampling unit 31 may be connected to the main output terminal or the total output terminal, so as to sample the first feedback voltage and transmit the first sampled voltage to the first conditioning feedback unit 32. The first conditioning feedback unit 32 generates a first switch driving signal based on the first feedback voltage, and transmits the first switch driving signal to the control terminal of the main power switch Q1 to control the on/off of the main power switch Q1. The first sampling unit 31, the first conditioning feedback unit 32, the main power switch Q1, the voltage conversion unit 12 and the main output terminal or the total output terminal form a first feedback loop, and the main output voltage Vo1 can be directly controlled by controlling the on/off of the main power switch Q1 through the first feedback loop, so that the total output voltage Vo is indirectly controlled, and the closed-loop control of the main output voltage Vo1 or the total output voltage Vo is realized.

In the embodiment of the present application, the PFC controller 30 controls the on/off of the main power switch Q1, so as to realize closed-loop control of the main output voltage or the total output voltage, and simultaneously control the input current and the output current to be sine waves with the same frequency and phase, so as to achieve power factor correction and higher power factor.

In one possible implementation, referring to fig. 4, the first sampling unit 31 includes a first sampling terminal a1, a second sampling terminal a2, and a third sampling terminal a 3; the first conditioning feedback unit 32 includes: the circuit comprises a first comparator U1, a second comparator U2, a third comparator U3, a first reference voltage source Vr1, a first sawtooth wave signal source Vramp1 and a trigger U4.

An output terminal of the first reference voltage source Vr1 is connected to a positive input terminal of the first comparator U1, and the first sampling terminal a1 is connected to a negative input terminal of the first comparator U1; an output terminal of the first comparator U1 is connected to a positive input terminal of the second comparator U2, and an inverted input terminal of the second comparator U2 is connected to the second sampling terminal a 2; an output terminal of the second comparator U2 is connected to a positive input terminal of the third comparator U3, the first sawtooth signal source Vramp1 is connected to a negative input terminal of the third comparator U3, an output terminal of the third comparator U3 is connected to a first input terminal of the flip-flop U4, the third sampling terminal a3 is connected to a second input terminal of the flip-flop U4, and an output terminal of the flip-flop U4 is connected to a control terminal of the main power switch Q1.

The first comparator U1 receives a first feedback voltage from the first sampling terminal a1 and a first reference voltage signal from the first reference voltage source Vr1, and compares the first feedback voltage with the reference voltage to generate a first voltage error signal.

The second comparator U2 receives the switching tube voltage signal from the second sampling terminal a2 and the first voltage error signal from the first comparator U1, compares the first voltage error signal with the switching tube voltage signal to obtain the current control signal of the main power switching tube Q1, and the switching tube voltage signal is converted from the current signal of the main power switching tube Q1.

The third comparator U3 receives the current control signal from the second comparator U2 and the first sawtooth wave signal from the first sawtooth wave signal source Vramp1, and compares the current control signal with the sawtooth wave signal to obtain a stop pulse signal; the third sampling terminal a3 samples the energy release signal of the voltage conversion unit 12 to form a start pulse signal.

The flip-flop U4 receives the stop pulse signal and the start pulse signal, and generates the first switch driving signal for controlling the on/off of the main power switch Q1 based on the start pulse signal and the stop pulse signal.

Specifically, the first sampling terminal a1 may be directly connected to the main output terminal and the auxiliary output terminal to sample the main output voltage Vo1 and the auxiliary output voltage Vo2, and select whether to feedback the main output voltage Vo1 or the auxiliary output voltage Vo2 through the electronically gated switch S to form the first feedback voltage. The first sampling terminal a1 selects the feedback auxiliary output voltage Vo2 through the electronically gated switch S during the constant current charging phase of the normal charging process of the secondary battery 60, and the first sampling terminal a1 selects the feedback main output voltage Vo1 through the electronically gated switch S during the constant voltage charging phase.

The second sampling end a2 can detect the current of the main power switch tube Q1 through a resistor Ri and convert the current into a voltage signal to form a switch tube voltage signal; the third sampling terminal a3 can detect the energy release signal of the voltage transformation unit 12 through the resistor Rdem to form a start pulse signal. The first sampling terminal a1 transmits the sampled first feedback voltage to the inverting input terminal of the first comparator U1. A positive input terminal of the first comparator U1 is connected to a first reference voltage source Vr1, and the first reference voltage source Vr1 transmits a first reference voltage to a positive input terminal of the first comparator U1. The first comparator U1 compares the first feedback voltage with the first reference voltage to obtain a voltage error signal, and amplifies the voltage error signal and outputs the amplified voltage error signal to the positive input terminal of the second comparator U2. The second sampling terminal a2 transmits the switch tube voltage signal to the inverting input terminal of the second comparator U2 to control the peak current of the main power switch tube Q1. The second comparator U2 compares the first voltage error signal with the switch tube voltage signal to form a control signal for the main power switch Q1, which is transmitted to the positive input terminal of the third comparator U3. The third comparator receives a standard sawtooth wave signal from the first sawtooth wave signal source Vramp1, compares the standard sawtooth wave signal with a control signal to form a stop pulse signal, and transmits the stop pulse signal to the first input terminal of the flip-flop U4. The third sampling terminal a3 transmits a start pulse signal to the second input terminal of the flip-flop U4. The flip-flop U4 generates a switch driving signal based on the start pulse signal and the stop pulse signal, and transmits the generated switch driving signal to the control terminal of the main power switch Q1 to control the on/off of the main power switch Q1. The switch driving signal may be a Pulse Width Modulation (PWM) switch driving signal, and the flip-flop may be a Reset-Set (RS) flip-flop.

In the embodiment of the present application, the voltage magnitude of the reference voltage is constant, and the PFC controller 30 controls the sampled main output voltage Vo1 or the total output voltage Vo to be equal to the reference voltage in real time through sampling, conditioning and feedback, so as to realize closed-loop control of the main output voltage Vo1 or the total output voltage Vo. By using the PFC controller 30 with the above structure, the PFC main converter 10 can be precisely controlled, and the PFC controller is simple to manufacture, low in cost, and high in control precision.

In one possible embodiment, the control modes of the PFC controller 30 include: one of a current critical conduction mode, a current discontinuous conduction mode, and a current continuous conduction mode.

In the current critical conduction mode, the PFC controller 30 detects the energy release signal of the voltage conversion unit 12 through the third sampling terminal a 3. After the last conduction period of the main power switch Q1 is finished and before the next conduction period, the energy of the voltage conversion unit 12 is completely released, and the secondary side current of the secondary winding 122 is attenuated to zero. The conduction frequency of the main power switch Q1 varies with line voltage and battery 60.

In the current discontinuous conduction mode, the PFC controller 30 does not need to detect the energy release signal of the voltage conversion unit 12, and the conduction frequency of the main power switch Q1 varies with the magnitude of the input voltage. In the current continuous conduction mode, the conduction frequency of the main power switch Q1 is constant, and the conduction duty ratio varies with the magnitude of the input voltage.

In the embodiment of the application, different control modes can be selected according to actual needs, and the method can be adapted to different circuit structures so as to realize power factor correction in each circuit.

In one possible implementation, referring to fig. 4, the DC/DC auxiliary converter 20 includes an auxiliary power switch Q2, an inductor L2, and a rectifier diode D7.

One end of an auxiliary power switch tube Q2 is connected with one pole of an auxiliary input end of the DC/DC auxiliary converter 20, the other end of the auxiliary power switch tube Q2 is connected with one end of an inductor L2, the other end of the inductor L2 is connected with the port 7 of the auxiliary output end, one end of a rectifier diode D7 is connected between the other end of the auxiliary power switch tube Q2 and one end of an inductor L2, and the other end of the rectifier diode D7 is connected between the other pole of the auxiliary input end of the DC/DC auxiliary converter 20 and the port 8 of the auxiliary output end;

when the auxiliary power switch Q2 is turned on, the rectifier diode D7 is turned off, the auxiliary input terminal of the DC/DC auxiliary converter 20 receives the DC output voltage to supply the inductor L2 with electric energy, and the inductor L2 stores the electric energy.

Under the condition that the auxiliary power switch tube Q2 is cut off, the rectifier diode D7 is conducted, the inductor L2, the rectifier diode D7 and the auxiliary output end form a current loop, the inductor L2 releases electric energy to provide electric energy for the auxiliary output end, and the auxiliary output end outputs an auxiliary output voltage Vo 2.

Specifically, when the auxiliary power output switching tube Q2 is turned on, the diode D7 is turned off, the auxiliary input terminal of the DC/DC auxiliary converter 20 is connected to the inductor L2 to supply electric energy to the inductor L2, and the inductor L2 stores the electric energy and outputs the electric energy to the auxiliary output terminal, so that the auxiliary output terminal outputs the auxiliary output voltage Vo 2. When the auxiliary power switch Q2 is turned off, the diode D7 is turned on, and the inductor L2 forms a current loop with the auxiliary terminal and the diode D7. The inductor L2 releases the electrical energy to provide electrical energy to the auxiliary output port, so that the auxiliary output port outputs the auxiliary output voltage.

In the embodiment of the application, the auxiliary output voltage can be controlled by controlling the on and off of the auxiliary power switch tube, and the auxiliary power switch tube is simple to manufacture and low in cost.

In one possible implementation, referring to fig. 4, the DC/DC controller 40 includes a fourth comparator U5, a fifth comparator U6, a sixth comparator U7, a current reference source Iref, a second reference voltage source Vr2, a second sawtooth signal source Vramp2, a current sampling terminal b1, a voltage sampling terminal b2, and a logic or circuit 43, the fourth comparator U5, the fifth comparator U6, the current reference source Iref, and the current sampling terminal b1 form a current feedback loop 42, and the sixth comparator U7, the fifth comparator U6, and the second reference voltage source Vr2 form a voltage feedback loop 41.

The positive input end of the fourth comparator U5 is connected with the output end of the current reference source Iref, the negative input end of the fourth comparator U5 is connected with the current sampling end b1, and the output end of the fourth comparator U5 is connected with the first input end of the logic OR circuit 43; a positive input end of the sixth comparator U7 is connected with an output end of the second reference voltage source Vr2, a negative input end of the sixth comparator U7 is connected with the voltage sampling end b2, and an output end of the sixth comparator U7 is connected with a second input end of the or logic circuit 43; an output terminal of the or-logic circuit 43 is connected to a positive input terminal of a fifth comparator U6, an inverting input terminal of the fifth comparator U6 is connected to an output terminal of a second sawtooth signal source Vramp2, and an output terminal of the fifth comparator U6 is connected to a control terminal of the DC/DC controller 40.

The fourth comparator U5 receives the current feedback signal from the current sampling terminal b1 and the reference current from the current reference source Iref, and compares the reference current with the current feedback signal to form a current error signal.

The sixth comparator U7 receives the second feedback voltage from the voltage sampling terminal b2 and the second reference voltage from the second reference voltage source Vr2, compares the second feedback voltage with the reference voltage, and forms a second voltage error signal.

The fifth comparator U6 receives the current error signal or the second voltage error signal and a sawtooth signal from a second sawtooth signal source Vramp2, compares the sawtooth signal with the current error signal or the second voltage error signal, and forms a second switching tube driving signal, wherein the second switching tube driving signal is used for controlling the on and off of the auxiliary power switch Q2.

Specifically, the current sampling terminal b1 may detect the total current Io through the resistor Ro, that is, detect the charging current of the battery 60, convert the detected total current Io into a voltage signal, form a current feedback signal Ios, and transmit the current feedback signal Ios to the fourth comparator U5. The current reference source Iref transmits a current reference signal to the fourth comparator U5. The fourth comparator U5 compares the current feedback signal with the current reference signal to obtain a current error signal, amplifies the current error signal and transmits the amplified current error signal to the first input terminal of the or logic circuit 43.

The voltage sampling terminal b2 may be connected to the main output terminal to sample the main output voltage Vo, form a second feedback voltage Vos, and transmit the second feedback voltage Vos to the sixth comparator U7. The second reference voltage source Vr2 transmits a second reference voltage signal to the sixth comparator U7. The sixth comparator U7 compares the second voltage feedback signal Vos with the second reference voltage signal to form a second voltage error signal, and transmits the second voltage error signal to a second input terminal of the or logic circuit 43.

The or circuit 43 may automatically enable one of the current control loop 42 and the voltage control loop 41 according to the magnitude of the current error signal and the voltage error signal, so that the fifth comparator U6 receives the current error signal or the voltage error signal. The second sawtooth wave signal source Vramp2 transmits the second sawtooth wave signal to the fifth comparator U6, and the fifth comparator compares the received current error signal or voltage error signal with the second sawtooth wave signal to form a second switch driving signal, and the second switch driving signal is used for controlling the on and off of the auxiliary power switch Q2.

In the constant current charging stage of the normal charging process of the storage battery 60, the or circuit 43 enables the current control loop 42, and the fifth comparator U6 receives the current error signal and compares the current error signal with the second sawtooth wave signal to form a second switch driving signal, which is used for controlling the on and off of the auxiliary power switch Q2 to control the output current of the DC/DC auxiliary converter 20, so as to realize the closed-loop control of the total current Io, that is, the closed-loop control of the charging current of the storage battery 60.

In the constant voltage charging stage of the normal charging process of the storage battery 60, the or circuit 43 enables the voltage control loop 41, and the fifth comparator U6 receives the voltage error signal and compares the voltage error signal with the second sawtooth wave signal to form a second switch driving signal, which is used for controlling the on and off of the auxiliary power switch Q2 to control the auxiliary output voltage Vo2 output by the DC/DC auxiliary converter 20, so as to indirectly control the main output voltage Vo and realize the closed-loop control of the main output voltage Vo, that is, the closed-loop control of the charging voltage of the storage battery 60.

In the embodiment of the present application, the DC/DC controller 40 is a fast-loop control, the frequency of the output second switch driving signal is greater than the frequency of the first switch driving signal, and the DC/DC auxiliary converter 20 responds to the second switch driving signal quickly, so that the total output voltage Vo is equal to the second reference voltage in real time in the constant-current charging phase and the total output current Io is equal to the reference current in real time in the constant-voltage charging phase, thereby realizing the closed-loop control of the charging current or the charging voltage of the battery 60. The frequency of the second switch drive signal may be controlled by a second sawtooth signal source Vramp 2. The DC/DC controller 40 having the above-described configuration controls the DC/DC auxiliary converter 20 to accurately control the charging current or the charging voltage of the battery 60.

In one possible implementation, referring to fig. 4, the or circuit 43 includes a first diode Di and a second diode Dv.

The anode of the first diode Di is connected to the output terminal of the or circuit 43, and the cathode of the first diode Di is connected to the first input terminal of the or circuit.

The anode of the second diode Dv is connected between the anode of the first diode Di and the output terminal of the or circuit 43, and the cathode of the second diode Dv is connected to the second input terminal of the or circuit 43.

Specifically, in the case where the current feedback signal is greater than the current reference signal, the fourth comparator U5 outputs a low level, the first diode Di is turned on, and the or logic circuit 43 enables the current control loop 42. In the case where the current feedback signal is greater than the current reference signal, the fourth comparator U5 outputs a high level, and the first diode Di is turned off.

In case the second voltage feedback signal is greater than the second reference voltage signal, the sixth comparator U7 outputs a low level, the second diode Dv is turned on, and the logical or circuit 43 enables the voltage control loop 41. In the case where the second voltage feedback signal is greater than the second reference voltage signal, the sixth comparator U7 outputs a high level, and the second diode Dv is turned off.

As can be seen from the above, when the fourth comparator U5 outputs a low level and the sixth comparator U7 outputs a high level, i.e., the current error signal is low, the second voltage error signal is high, Di is turned on, Dv is turned off, and the or logic circuit 43 enables the current control loop 42; when the fourth comparator U5 outputs a high level and the sixth comparator U7 outputs a low level, i.e., the current error signal is high, the second voltage error signal is low, Di is off, Dv is on, and the or circuit 43 enables the voltage control loop 41. I.e. the or logic circuit 43 is capable of automatically enabling one of the current control loop 42 and the voltage control loop 41 depending on the magnitude of the current error signal and the second voltage error signal.

In the embodiment of the present application, the first diode Di and the second diode Dv form a logic or circuit, which has a simple structure and a low cost.

In a possible embodiment, the PFC main converter includes one of a flyback converter, a boost converter, a buck-boost converter, a buck converter and a forward converter.

Referring to fig. 4, the PFC main converter 10 includes a power conversion unit 11, a rectifier diode D5, a rectifier diode Db, a voltage conversion unit 12, and a main power switch Q1. The several units may constitute a PFC main converter 10 of an isolated or non-isolated type such as a buck converter, a boost converter, and a buck-boost converter. The main power switch tube Q1 also has a body diode D_Q1. The input terminal of the PFC main converter 10 comprises port 1 and port 2, the main output terminal comprises port 3 and port 4, and the dc output terminal comprises port 5 and port 6.

The power conversion unit 11 may include an LC filter circuit including a capacitor Cf and an inductor Lf, a diode full bridge rectifier circuit including a diode D1, a diode D2, a diode D3, and a diode D4, and a filter capacitor Cin.

One end of the inductor Lf is connected to the port 1 of the input end of the main PFC converter 10, the other pole of the inductor Lf is connected to one end of the capacitor Cf, the other end of the capacitor Cf is connected to the port 2 of the input end of the main PFC converter 10, and the two ends of the capacitor Cf constitute the output end of the LC filter circuit. The negative electrode of D1 is connected with the negative electrode of D2, the positive electrode of D2 is connected with the negative electrode of D4, the positive electrode of D4 is connected with the positive electrode of D3, and the negative electrode of D3 is connected with the positive electrode of D1; one pole of the output end of the LC filter circuit is connected between the positive pole of D1 and the negative pole of D3, the other pole of the output end of the LC filter circuit is connected between the positive pole of D2 and the negative pole of D4, one end of a filter capacitor Cin is connected between the negative pole of D1 and the negative pole of D2, and the other end of the filter capacitor Cin is connected between the positive pole of D3 and the positive pole of D4. Both ends of the filter voltage Cin constitute the output end of the power conversion unit 11.

Referring to fig. 4, the circuit configuration of the flyback converter type PFC main converter 10 is described in detail as follows:

the voltage conversion unit 12 comprises a double-winding transformer T1, one end of the primary side of the T1 main winding 121 is connected with one end of a main power switch tube Q1, the other end of the primary side of the T1 main winding 121 is connected with one end of the output end of the power conversion unit 11, and the other end of the main power switch tube Q1 is connected with the other end of the output end of the power conversion unit 11. One end of the secondary side of the T1 main winding 121 is connected to one end of the diode D5, the other end of D5 is connected to port 3, and the other end of the secondary side of the T1 main winding 121 is connected to port 4. One end of the secondary side of the T1 auxiliary winding 122 is connected to one end of the diode Db, the other end of the Db is connected to port 5, and the other end of the secondary side of the T1 auxiliary winding 122 is connected to port 6.

Referring to fig. 5, the configuration of the main PFC converter 10 of the buck converter type is described in detail as follows:

the voltage converting unit 12 comprises a two-winding inductor L1, and the inductor L1 comprises a main winding 121 and an auxiliary winding 122. One end of a main power switch tube Q1 is connected with one port of the output end of the power conversion unit 11, the other end of the main power switch tube Q1 is connected with one end of an L1 main winding 121, the control end of the main power switch tube Q1 is connected with the output end of the PFC controller 30, and the other end of the L1 main winding 121 is connected with the port 3 of the main output end. One end of the rectifier diode D5 is connected between one end of the power switching tube and one end of the main winding 121, and the other end of D5 is connected to the other port of the output terminal of the power conversion unit 11 and to the port 4 of the main output terminal. The rectifier diode Db is connected between one end of the auxiliary winding 122 and the port 5 of the dc output terminal, and the other end of the auxiliary winding 122 is connected to the port 6 of the dc output terminal.

Referring to fig. 6, the following details the configuration of the boost converter type PFC main converter 10:

the voltage converting unit 12 comprises a two-winding inductor L1, and the inductor L1 comprises a main winding 121 and an auxiliary winding 122. One end of the main winding 121 is connected to one port of the output end of the power conversion unit 11, the other end of the main winding 121 is connected to one end of the main power switch Q1, the other end of the main power switch Q1 is connected to the other port of the output end of the power conversion unit 11, and the other end of the main power switch Q1 is further connected to the port 4 of the main output end; one end of the rectifier diode D5 is connected between the other end of the main winding 121 and one end of the main power switch Q1, and the other end of D5 is connected to port 3 of the main output terminal. The rectifier diode Db is connected between one end of the auxiliary winding 122 and the port 5 of the dc output terminal, and the other end of the auxiliary winding 122 is connected to the port 6 of the dc output terminal.

Referring to fig. 7, the following details the structure of the buck-boost converter type PFC main converter 10:

the voltage converting unit 12 includes a double winding inductor L1, and the double winding inductor L1 includes a main winding 121 and an auxiliary winding 122. One end of the main power switch Q1 is connected to one port of the output terminal of the power conversion unit 11, and the other end of the main power switch Q1 is connected to the port 4 of the main output terminal. One end of the main winding 121 is connected between the other end of the main power switch Q1 and the port 4, the other end of the main winding 121 is connected to the other port of the output end of the power conversion unit 11, one end of the rectifier diode D5 is connected between the other end of the main winding 121 and the other port of the output end of the power conversion unit 11, and the other end of D5 is connected to the port 3 of the main output end. The rectifier diode Db is connected between one end of the auxiliary winding 122 and the port 5 of the dc output terminal, and the other end of the auxiliary winding 122 is connected to the port 6 of the dc output terminal.

In one possible embodiment, the DC/DC auxiliary converter 20 includes one of a flyback converter, a boost converter, a buck-boost converter, a buck converter, a forward converter, a bridge converter, a push-pull converter, a single-ended primary inductive converter, and an LLC resonant converter.

The DC/DC auxiliary converter 20 includes an auxiliary power switch Q2, an inductor L2 (or transformer T2), and a rectifier diode D7. The auxiliary power switch Q2, inductor L2, and rectifier diode D7 may form an isolated or non-isolated type of DC/DC auxiliary converter 20 such as a buck converter, a boost converter, and a buck-boost converter. The auxiliary power switch tube Q2 also has a body diode D_Q2. The auxiliary output of the DC/DC auxiliary converter 20 comprises a port 7 and a port 8, and the auxiliary input of the DC/DC auxiliary converter 20 is connected to the

ports

5 and 6 of the DC output.

Referring to fig. 4, the construction of the buck converter type DC/DC auxiliary converter 20 is described in detail below:

the DC/DC auxiliary converter 20 includes an auxiliary power switch Q2, an inductor L2, and a rectifier diode D7. One end of the auxiliary power switch tube Q2 is connected to the port 5 of the dc output terminal, the other end of the auxiliary power switch tube Q2 is connected to one end of the inductor L2, and the other end of the inductor L2 is connected to the port 7 of the auxiliary output terminal. One end of the rectifier diode D7 is connected between the other end of the auxiliary power switch Q2 and one end of the inductor L2, and the other end of the rectifier diode D7 is connected to both the port 6 of the dc output terminal and the port 8 of the auxiliary output terminal.

Referring to fig. 8, the constitution of the boost converter type DC/DC auxiliary converter 20 is described in detail as follows:

the DC/DC auxiliary converter 20 includes an auxiliary power switch Q2, an inductor L2, and a rectifier diode D7. One end of the inductor L2 is connected to the port 5 of the dc output terminal, and the other end is connected to one end of the rectifier diode D7. The other end of the rectifying diode D7 is connected to port 7 of the auxiliary output terminal. One end of the auxiliary power switch Q2 is connected between the port 6 of the dc output terminal and the port 8 of the auxiliary output terminal, and the other end is connected between the other end of the inductor L2 and one end of the rectifier diode D7.

Referring to fig. 9, the structure of the buck-boost converter type DC/DC auxiliary converter 20 is described in detail below:

the DC/DC auxiliary converter 20 includes an auxiliary power switch Q2, an inductor L2, and a rectifier diode D7. One end of the auxiliary power switch tube Q2 is connected to the port 5 of the dc output terminal, and the other end is connected to the port 8 of the auxiliary output terminal. A rectifier diode D7 is connected between port 6 of the dc output and port 7 of the auxiliary output. One end of an inductor L2 is connected between the other end of the auxiliary power switch tube Q2 and the port 8 of the auxiliary output terminal, and the other end of the inductor L2 is connected between the port 6 and the rectifier diode D7.

Referring to fig. 10, the structure of the negative voltage buck converter type DC/DC auxiliary converter 20 is described in detail below:

the DC/DC auxiliary converter 20 includes an auxiliary power switch Q2, an inductor L2, and a rectifier diode D7. One end of the auxiliary power switch Q2 is connected to one end of the inductor L2, and the other end is connected to the port 5 of the dc output terminal. The other end of the inductor L2 is connected to port 7 of the auxiliary output terminal. One end of the rectifier diode D7 is connected between the port 6 of the dc output terminal and the port 8 of the auxiliary output terminal, and the other end is connected between one end of the auxiliary power switch Q2 and one end of the inductor L2.

Referring to fig. 11, the configuration of the flyback converter type DC/DC auxiliary converter 20 is described in detail below:

the DC/DC auxiliary converter 20 includes an auxiliary power switch Q2, a transformer T2, and a rectifier diode D7. The transformer T2 comprises a first winding and a second winding, wherein one end of the first winding is connected with a port 5 of the direct current output end, and the other end of the first winding is connected with one end of an auxiliary power switch tube Q2; the other end of the auxiliary power switch tube Q2 is connected with a port 6 of the direct current output end; one end of the second winding of the transformer T2 is connected to one end of the rectifier diode D7, the other end of the rectifier diode D7 is connected to the port 7 of the auxiliary output terminal, and the other end of the second winding is connected to the port 8 of the auxiliary output terminal.

In addition, the circuit is also provided with filter capacitors Co1, Cb and Co2, wherein the filter capacitor Co1 is connected between the port 3 and the port 4 of the main output end to filter the main output voltage Vo1 output by the main output end. The filter capacitor Cb is connected between the port 5 and the port 6 of the dc output terminal, and filters the dc output voltage output from the dc output terminal. The filter capacitor Co2 is connected between the port 7 and the port 8 of the auxiliary output terminal, and filters the auxiliary output voltage Vo2 output from the auxiliary output terminal.

In one possible embodiment, the voltage stress of the DC/DC auxiliary converter 20 is smaller than a first threshold value, and the current stress of the DC/DC auxiliary converter 20 is smaller than a second threshold value.

Specifically, the main output voltage Vo1 is greater than the auxiliary output voltage Vo2, the PFC main converter 10 provides most of the output power to the battery 60, and the DC/DC auxiliary converter 20 provides a small portion of the output power to the battery 60. Therefore, the voltage stress and the current stress of the power device in the DC/DC auxiliary converter 20 are small, thereby reducing the component cost.

In a possible embodiment, the PFC controller 30 further includes a first communication unit, and the DC/DC controller 40 further includes a second communication unit, where the first communication unit establishes a communication connection with the second communication unit.

In the embodiment of the application, the PFC controller 30 and the DC/DC controller 40 have a communication connection therebetween, the PFC controller 30 and the DC/DC controller 40 coordinate respective control and operation based on the communication connection, and the PFC controller 30 and the DC/DC controller 40 can send real-time instructions and operation parameters to each other, set a control mode, and adjust an operating state, so as to optimize the operation of the PFC main converter 10 and the DC/DC auxiliary converter 20, which can further improve the performance and reliability of the AC/DC charger.

Alternatively, in a possible embodiment, the PFC controller 30 and the DC/DC controller 40 may be integrated into one, two or more analog chips, or one, two or more digital chips such as MCU, DSP, etc. may be used, which require embedded software programming, and the operation principle thereof is the same as that of the PFC controller 30 and the DC/DC controller 40 in the above embodiments, and will not be described again here.

It should be understood that the application of the present application is not limited to the above examples, and that modifications or changes may be made by those skilled in the art based on the above description, and all such modifications and changes are intended to fall within the scope of the appended claims.

Claims

1. An AC/DC charger, comprising: a power factor correction PFC main converter, a DC/DC auxiliary converter, a PFC controller and a DC/DC controller;

The PFC main converter includes a main output terminal and a DC output terminal, the DC output terminal is connected to the auxiliary input terminal of the DC/DC auxiliary converter, and the main output terminal is connected to the DC/DC auxiliary converter. Auxiliary output terminals are connected in series to form a total output terminal;

The control end of the PFC controller is connected to the PFC main converter, and the DC/DC controller includes a voltage control loop and a current control loop; the output end of the voltage control loop and the output end of the current control loop are respectively connected with the control terminal of the DC/DC controller, and the control terminal of the DC/DC controller is connected with the DC/DC auxiliary converter;

The PFC main converter outputs the main output voltage through the main output terminal; the PFC main converter transmits the output DC output voltage to the auxiliary input terminal of the DC/DC auxiliary converter through the DC output terminal; The DC/DC auxiliary converter processes the DC output voltage to obtain an auxiliary output voltage, the ripple of the auxiliary output voltage is opposite to the ripple phase of the main output voltage, and the auxiliary output terminal outputs all the voltages. the auxiliary output voltage;

The total output terminal receives the main output voltage and the auxiliary output voltage to form a total output voltage and an output total current; the PFC controller samples a first feedback voltage, and uses the first feedback voltage to control the PFC The input voltage of the main converter has the same frequency and phase as the input current; the voltage control loop samples the second feedback voltage, and uses the second feedback voltage to control the auxiliary output output by the auxiliary output terminal of the DC/DC auxiliary converter The ripple of the voltage is opposite in phase to the ripple of the main output voltage; the current control loop samples the total current, and uses the total current to control the DC/DC auxiliary converter;

The first feedback voltage includes one of the main output voltage and the auxiliary output voltage, and the second feedback voltage includes the total output voltage.

2. The AC/DC charger according to claim 1, wherein the PFC main converter further comprises a power conversion unit, a main power switch tube and a voltage conversion unit,

The main power switch tube is connected between the output end of the power conversion unit and the input end of the voltage conversion unit, the control end of the main power switch tube is connected with the control end of the PFC controller, the The output end of the voltage conversion unit is connected with the main output end and the DC output end;

the PFC controller controls the on and off of the main power switch;

When the main power switch tube is turned on, the power conversion unit provides electric energy for the voltage conversion unit, and the voltage conversion unit stores electric energy;

When the main power switch tube is turned off, the power conversion unit stops supplying electric energy to the voltage conversion unit, and the voltage conversion unit releases the electric energy.

3. The AC/DC charger according to claim 2, wherein the voltage conversion unit comprises a main winding and an auxiliary winding;

One end of the main winding is connected to one end of the main power switch tube, the other end of the main winding is connected to the main output end; one end of the auxiliary winding is connected to one end of the main power switch tube, so The other end of the auxiliary winding is connected to the auxiliary output end;

The voltage conversion unit outputs the main output voltage to the main output terminal through the main winding; the voltage conversion unit outputs the DC output voltage to the DC output terminal through the auxiliary winding.

4. The AC/DC charger according to claim 3, wherein the PFC controller comprises a sampling unit and a conditioning feedback unit;

The output end of the sampling unit is connected to the input end of the conditioning feedback unit, and the output end of the conditioning feedback unit is connected to the control end of the main power switch tube;

The sampling unit is used for: sampling the first feedback voltage; the conditioning feedback unit is used for: generating a first switch tube drive signal based on the first feedback voltage; the first switch tube drive signal is used to control all The main power switch tube.

5. The AC/DC charger according to claim 4, wherein the sampling unit comprises a first sampling terminal, a second sampling terminal and a third sampling terminal; the conditioning feedback unit comprises: a first comparator , a second comparator, a third comparator, a first reference voltage source, a first sawtooth wave signal source, and a trigger;

The output terminal of the first reference voltage source is connected to the forward input terminal of the first comparator, and the first sampling terminal is connected to the reverse input terminal of the first comparator; the first comparator The output terminal of the second comparator is connected to the forward input terminal of the second comparator, and the reverse input terminal of the second comparator is connected to the second sampling terminal; the output terminal of the second comparator is connected to the second sampling terminal. The forward input terminals of the three comparators are connected, the first sawtooth wave signal source is connected to the reverse input terminal of the third comparator, and the output terminal of the third comparator is connected to the first input of the flip-flop The third sampling end is connected with the second input end of the flip-flop, and the output end of the flip-flop is connected with the control end of the PFC controller;

The first comparator receives a first feedback voltage from the first sampling terminal and a first reference voltage signal from the first reference voltage source, and compares the first feedback voltage with the first reference voltage signal, forming a first voltage error signal;

The second comparator receives the switch voltage signal from the second sampling terminal and the first voltage error signal from the first comparator, and compares the first voltage error signal with the switch voltage signal to obtain The control signal of the main power switch tube, the voltage signal of the switch tube is obtained by converting the current signal of the main power switch tube;

The third comparator receives the current control signal from the second comparator and the first sawtooth wave signal from the first sawtooth wave signal source, and compares the control signal with the sawtooth wave signal to obtain stop pulse signal; the third sampling terminal samples the electric energy of the voltage conversion unit to form a start pulse signal;

The trigger receives the stop pulse signal and the start pulse signal, generates the first switch driving signal based on the start pulse signal and the stop pulse signal, and the first switch driving signal is used to control the The on and off of the main power switch tube.

6. The AC/DC charger according to claim 1, wherein the DC/DC auxiliary converter comprises an auxiliary power switch tube, an inductor and a rectifier diode;

One end of the auxiliary power switch tube is connected to one pole of the auxiliary input end of the DC/DC auxiliary converter, the other end of the auxiliary power switch tube is connected to one end of the inductance, and the other end of the inductance is connected to the other end of the inductance. One pole of the auxiliary output end is connected, one end of the rectifier diode is connected between the other end of the auxiliary power switch tube and one end of the inductor, and the other end of the rectifier diode is connected to the DC/DC auxiliary converter between the other pole of the auxiliary input end of the device and the other pole of the auxiliary output end;

When the auxiliary power switch is turned on, the rectifier diode is turned off, and the auxiliary input terminal of the DC/DC auxiliary converter receives the DC output voltage to provide electrical energy for the inductor, and the inductor stores electrical energy ;

When the auxiliary power switch tube is turned off, the rectifier diode is turned on, the inductor, the rectifier diode and the auxiliary output end form a current loop, and the inductor releases electric energy to provide the auxiliary output end electric energy, so that the auxiliary output terminal outputs the auxiliary output voltage.

7. The AC/DC charger according to claim 1, wherein the DC/DC controller comprises a fourth comparator, a fifth comparator, a sixth comparator, a current reference source, and a second reference voltage source, a second sawtooth wave signal source, a current sampling terminal, a voltage sampling terminal and a logic OR circuit, the fourth comparator, the fifth comparator, the current reference source and the current sampling terminal constitute the current a feedback loop, the sixth comparator, the fifth comparator, and the second reference voltage source constitute the voltage feedback loop;

The forward input end of the fourth comparator is connected to the output end of the current reference source, the reverse input end of the fourth comparator is connected to the current sampling end, and the output end of the fourth comparator connected with the first input terminal of the logic OR circuit; the forward input terminal of the sixth comparator is connected with the output terminal of the second reference voltage source, and the reverse input terminal of the sixth comparator is connected with the output terminal of the second reference voltage source. the voltage sampling end is connected, the output end of the sixth comparator is connected with the second input end of the logic OR circuit; the output end of the logic OR circuit is connected with the forward input end of the fifth comparator, The reverse input end of the fifth comparator is connected with the output end of the second sawtooth wave signal source, and the output end of the fifth comparator is connected with the control end of the DC/DC controller;

the fourth comparator receives the current feedback signal from the current sampling terminal and the current reference signal from the current reference source, and forms a current error signal after comparing the current reference signal and the current feedback signal;

The sixth comparator receives the second feedback voltage from the voltage sampling terminal and the second reference voltage signal from the second reference voltage source, and compares the second feedback voltage with the second reference voltage signal in the form of a second voltage error signal;

The fifth comparator receives the current error signal or the second voltage error signal and the second sawtooth signal from the sawtooth signal source, and compares the second sawtooth signal with the current error signal or The second voltage error signal forms a second switch tube drive signal, and the second switch tube drive signal is used to control the turn-on and turn-off of the auxiliary power switch.

8. The AC/DC charger of claim 7, wherein the logic OR circuit comprises a first diode and a second diode;

The anode of the first diode is connected to the output end of the logic OR circuit, and the cathode of the first diode is connected to the first input end of the logic OR circuit;

The anode of the second diode is connected between the anode of the first diode and the output terminal of the logic OR circuit, and the cathode of the second diode is connected to the second diode of the logic OR circuit. input connection.

9 . The AC/DC charger of claim 1 , wherein the voltage stress of the DC/DC auxiliary converter is less than a first threshold, and the current stress of the DC/DC auxiliary converter is less than a second threshold. 10 . .

10. The AC/DC charger according to claim 1, wherein the PFC controller comprises a first communication unit, the DC/DC controller comprises a second communication unit, the first communication unit is connected to The second communication unit establishes a communication connection.