CN116488472A - A control device, method, chip and power converter for a conversion circuit - Google Patents

Abstract

A control device, a control method, a chip and a power converter of a conversion circuit are used for improving the power supply stability of the conversion circuit. The control device is connected with a conversion circuit provided with an inverter circuit, a transformer and a rectifying circuit, and includes: the compensation circuit is connected with the inverter circuit and the rectifying circuit; the control circuit is connected with the compensation circuit and is connected with the inverter circuit and the rectifying circuit; the compensation circuit is used for acquiring the first voltage which is input to the inverter circuit at this time and adjacent times; according to a first difference value between the first voltages acquired in two adjacent times, compensating the first voltage acquired at this time to acquire a second voltage; compensating the second voltage according to parameters of a plurality of devices in the conversion circuit to obtain a third voltage; the control circuit is used for acquiring a fourth voltage output by the rectifying circuit, determining a target duty ratio according to the fourth voltage, the third voltage and the second voltage acquired at the time, and controlling the conduction of the switches in the rectifying circuit and the inverter circuit by using the target duty ratio.

Description

A control device, method, chip and power converter for a conversion circuit

technical field

The embodiments of the present application relate to the field of power supply technology, and in particular to a control device, method, chip and power converter for a conversion circuit.

Background technique

In application scenarios such as industrial power consumption or consumer electronic products, there will be a voltage mismatch between the power load and the power supply, and a conversion circuit will be set to achieve voltage conversion to meet the power demand of the power consumption equipment.

The conversion circuit is generally equipped with a transformer, which is used to realize the electrical isolation between the power supply and the load to ensure the safety of the power supply. In order to ensure the power supply stability of the conversion circuit, it is necessary to configure a controller for the conversion circuit. The controller can quickly adjust the duty cycle of the conversion circuit according to the input voltage change of the conversion circuit to ensure the stability of the output voltage of the conversion circuit. In practical applications, since the conversion module on the input side of the conversion circuit and the conversion module on the output side are connected through a transformer, in order to reduce the number of components required for signal isolation, a feed-forward control loop is generally introduced into the control loop of the controller, that is, the controller is placed on the primary side of the isolation transformer. Setting the controller on the primary side of the transformer does not need to configure an isolation auxiliary source, and can reduce the signals that need to be isolated and transmitted, reducing the control complexity and control cost of the conversion circuit. The output voltage will deviate from the ideal output voltage value.

Contents of the invention

The present application provides a control device, a method, a chip and a power converter for a conversion circuit, which are used to improve the power supply stability of the conversion circuit.

In a first aspect, the present application provides a control device for a conversion circuit, which is connected to the conversion circuit and used to control the operation of the conversion circuit. The conversion circuit includes an inverter circuit, a rectification circuit and a transformer connected between the inverter circuit and the rectification circuit. Specifically, the control device of the conversion circuit includes: a compensation circuit and a control circuit.

Wherein, the compensation circuit is used to connect with the inverter circuit and the rectifier circuit; the control circuit is connected to the compensation circuit, and is used to connect with the inverter circuit and the rectifier circuit; the compensation circuit is used to obtain the first voltage input to the inverter circuit this time and adjacently; according to the first difference between the first voltage obtained twice adjacently, the first voltage obtained this time is compensated to obtain the second voltage; according to the parameters of multiple devices in the conversion circuit, the second voltage is compensated to obtain the third voltage; , and use the target duty cycle to control the conduction of the switches in the rectifier circuit and the inverter circuit.

Using the above-mentioned control device, the difference between the first voltages acquired twice by the compensation circuit is the amplitude change value of the voltage received by the inverter circuit within a sampling period. Since the conduction of the switches in the inverter circuit and the rectifier circuit are both provided with a fixed period, the first voltage acquired this time can only be used to control the conduction of the switch in the next period. Therefore, the difference can be used to perform sampling delay compensation on the first voltage acquired this time to obtain the second voltage. In the conversion circuit, the inverter circuit is mainly used to convert the received DC voltage into an AC voltage. Therefore, the output voltage of the inverter circuit has the same amplitude as the input voltage, and the duty cycle required for the operation of the inverter circuit can be determined by using the second voltage obtained by the above compensation. Since the output voltage amplitude of the inverter circuit has been determined to be the compensated second voltage, according to the parameters of the device between the inverter circuit and the rectifier circuit, the second voltage can be determined to reach the third voltage after the rectifier circuit passes through the above device, and the fourth voltage output by the rectifier circuit can be obtained. When the input voltage and output voltage of the rectifier circuit are known, the duty cycle required for the rectifier circuit to maintain the output voltage can be determined, so that the voltage output from the rectifier circuit to the load is stable and the power supply stability of the conversion circuit is improved.

In a possible implementation manner, the compensation circuit includes: a first compensation unit and a second compensation unit. Wherein, the parameters of multiple devices in the conversion circuit include the transformation ratio of the transformer and the leakage inductance of the transformer.

Wherein, the first compensation unit is used to acquire the first voltage input to the inverter circuit this time and the adjacent one; according to the first difference, the first voltage acquired this time is added to obtain the second voltage. The second compensation unit is used to multiply the second voltage to obtain the fifth voltage according to the transformation ratio of the transformer; determine the leakage inductance voltage according to the leakage inductance of the transformer, and the leakage inductance voltage is the voltage at both ends of the leakage inductance of the transformer; and subtract the fifth voltage according to the leakage inductance voltage to obtain the third voltage.

With the above-mentioned control device, since the inverter circuit is mainly used to convert the received DC voltage into AC voltage, and does not perform voltage amplitude conversion, the voltage amplitude change generated by the second voltage after compensation reaching the rectifier circuit is mainly caused by the transformer, so compensation can be performed according to the transformation ratio of the transformer and the leakage inductance of the transformer to ensure the accuracy of the value.

In a possible implementation manner, the control device of the conversion circuit further includes a digital proportional-integral-derivative PID controller, one end of the digital PID controller is connected to the rectification circuit, and the other end of the digital PID controller is connected to the control circuit for obtaining the fourth voltage and outputting the fourth voltage to the control circuit.

Using the above control device, in order to prevent the difference between the fourth voltage amplitude and the ideal output voltage amplitude caused by the output voltage fluctuation, the PID controller can be used to stabilize the output voltage amplitude to ensure the power supply stability of the conversion circuit.

In a possible implementation manner, the control circuit includes: a first control unit and a second control unit.

Wherein, the first control unit is connected with the compensation circuit for connecting with the inverter circuit, determines the first duty ratio according to the second voltage, and controls the conduction of the switch in the inverter circuit according to the first duty ratio; the second control unit is connected with the compensation circuit for connection with the rectification circuit, controls the fourth voltage to divide the third voltage to obtain the second duty ratio, and controls the conduction of the switch in the rectification circuit according to the second duty ratio. The first duty ratio and the second duty ratio constitute a target duty ratio.

With the above control device, the functions of the inverter circuit and the rectifier circuit are different, and the inverter circuit and the rectifier circuit are respectively located in the primary winding and the secondary winding of the transformer. In order to realize the electrical isolation between the primary side and the secondary side of the transformer, a first control unit for controlling the inverter circuit and a second control unit for controlling the rectification circuit can be respectively configured in the control device.

In a possible implementation manner, in order to realize signal isolation between the input side and the output side of the conversion circuit, the control of the conversion circuit further includes an isolator, and the isolator may be connected between the digital PID controller and the rectification circuit, and between the control circuit and the rectification circuit.

Using the above-mentioned control device, the control device obtains the first voltage from the primary side of the transformer, and obtains the fourth voltage from the secondary side of the transformer. In order to realize electrical isolation between the primary side and the secondary side of the transformer, the fourth voltage output by the rectifier circuit can be signal-isolated by the isolator, and the signal output by the control circuit for controlling the rectifier circuit can be signal-isolated by the isolator, thereby realizing signal isolation on both sides of the transformer.

In a second aspect, the present application provides a chip connected to a conversion circuit. The conversion circuit includes an inverter circuit, a transformer, and a rectification circuit. The chip includes: a compensation circuit for connecting to the inverter circuit and a rectification circuit; a control circuit connected to the compensation circuit for connection to the inverter circuit and the rectification circuit; the compensation circuit is used to obtain the first voltage input to the inverter circuit this time and the adjacent one; according to the first difference between the first voltage obtained twice adjacently, the first voltage obtained this time is compensated to obtain a second voltage; according to the parameters of multiple devices in the conversion circuit, the second voltage is compensated to obtain a third voltage The control circuit is used to obtain the fourth voltage output by the rectifier circuit, determine the target duty ratio according to the fourth voltage, the third voltage and the second voltage obtained this time, and use the target duty ratio to control the conduction of the switches in the rectifier circuit and the inverter circuit.

In a third aspect, the present application provides a power converter, which includes a conversion circuit and a control device.

Wherein, the conversion circuit includes an inverter circuit, a transformer and a rectification circuit; the inverter circuit is used to connect the power supply through the input terminal of the conversion circuit, and converts the first voltage output by the power supply to a second voltage; the rectification circuit is used to connect the output terminal of the conversion circuit to the load, and convert the second voltage to a third voltage required for power supply of the load. The control device includes a compensation circuit and a control circuit; the compensation circuit is connected with the rectification circuit and the inverter circuit, and the control circuit is connected with the rectification circuit and the inverter circuit.

Wherein, the compensation circuit is used to obtain the first voltage input to the inverter circuit this time and the adjacent one; according to the first difference between the first voltage obtained twice adjacently, the first voltage obtained this time is compensated to obtain the fourth voltage; according to the parameters of multiple devices in the conversion circuit, the fourth voltage is compensated to obtain the fifth voltage; the control circuit is used to obtain the third voltage output by the rectifier circuit, and determine the target duty cycle according to the third voltage, the fourth voltage and the fifth voltage obtained this time, and use the target duty cycle to control the conduction of the switches in the rectifier circuit and the inverter circuit.

In a possible implementation manner, the inverter circuit and the rectification circuit are half-bridge conversion circuits or full-bridge conversion circuits.

In a fourth aspect, the present application provides a control method for a conversion circuit, which is applied to a conversion circuit, and the conversion circuit includes an inverter circuit, a transformer, and a rectification circuit. Specifically, the control method includes the following steps:

Obtaining the first voltage input to the inverter circuit this time and the adjacent one; according to the first difference between the first voltages obtained twice adjacently, compensating the first voltage obtained this time to obtain a second voltage; according to the parameters of a plurality of devices in the conversion circuit, compensating the second voltage to obtain a third voltage; obtaining a fourth voltage output by the rectifier circuit, determining a target duty cycle according to the fourth voltage, the third voltage, and the second voltage obtained this time, and using the target duty cycle to control the conduction of switches in the rectification circuit and the inverter circuit.

For the technical effects that can be achieved by any possible design in any one of the above-mentioned second to fourth aspects, please refer to the description of the technical effects that can be achieved by any possible design in the above-mentioned first aspect, and will not be repeated here.

Description of drawings

FIG. 1 is a structural schematic diagram 1 of a conversion circuit provided by an embodiment of the present application;

FIG. 2 is a schematic structural diagram II of a conversion circuit provided in an embodiment of the present application;

FIG. 3 is a schematic structural diagram III of a conversion circuit provided in an embodiment of the present application;

FIG. 4 is a first structural schematic diagram of a control device for a conversion circuit provided by an embodiment of the present application;

FIG. 5 is a schematic structural diagram II of a control device for a conversion circuit provided in an embodiment of the present application;

FIG. 6 is a schematic waveform diagram of a first voltage obtained by a compensation circuit provided in an embodiment of the present application;

FIG. 7 is a schematic diagram of a volt-second product waveform provided in an embodiment of the present application;

FIG. 8 is a schematic diagram of conduction of a switch in a rectifier circuit provided by an embodiment of the present application;

FIG. 9 is a schematic flowchart of a method for controlling a conversion circuit provided by an embodiment of the present application.

Detailed ways

Embodiments of the present application will be described in detail below in conjunction with the accompanying drawings.

The terms used in the embodiments of the present application are only used to explain specific embodiments of the present application, and are not intended to limit the present application. Apparently, the described embodiments are only some of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

It should be noted that the terms "first" and "second" in the description and claims of the present application and the above drawings are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the application described herein can be practiced in sequences other than those illustrated or described herein. The implementations described in the following exemplary embodiments do not represent all implementations consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with aspects of the present application as recited in the appended claims.

In the following, some terms used in the embodiments of the present application are explained, so as to facilitate the understanding of those skilled in the art.

(1) The term "plurality" in the embodiments of the present application refers to two or more, and other quantifiers are similar.

(2) The switching tube in the embodiment of the present application may be one or more of various types of switching tubes such as a relay, a metal oxide semiconductor field effect transistor (MOSFET), a bipolar junction transistor (BJT), an insulated gate bipolar transistor (IGBT), and a silicon carbide (SiC) transistor. List them all. The packaging form of each switch tube may be a single-tube package or a multi-tube package, which is not limited in this embodiment of the present application. Each switch tube may include a first terminal, a second terminal and a control terminal, wherein the control terminal is used to control the switch tube to be turned on or off. When the switch tube is turned on, current can be transmitted between the first end and the second end of the switch tube, and when the switch tube is turned off, no current can be transmitted between the first end and the second end of the switch tube. Taking a MOSFET as an example, the control terminal of the switching tube is the gate, the first terminal of the switching tube may be the source, and the second terminal may be the drain, or the first terminal may be the drain and the second terminal may be the source.

(3) "Connection" in the embodiment of the present application can be understood as an electrical connection, and the connection of two electrical components can be a direct or indirect connection between two electrical components. For example, the connection between A and B can be either direct connection between A and B, or indirect connection between A and B through one or more other electrical components, such as A and B connection, or A and C direct connection, C and B direct connection, A and B are connected through C. The "connection" in the embodiments of the present application may also be understood as a wireless connection, that is, the connection of two electrical components may be an electromagnetic connection of two electrical components.

(4) Direct current and alternating current. The direct current in the embodiment of the present application refers to an electrical form in which electric energy is conducted along a constant direction in a circuit. The conduction direction of electric energy is also called phase, and the phase of direct current can include positive or negative. The power intensity of most direct currents is fixed, and in some special direct currents (such as pulsed direct current), the power intensity will also change with time. Electric energy intensity is also called current amplitude. Common DC power sources include dry batteries, storage batteries, or DC generators. The alternating current in the embodiment of the present application refers to an electrical form in which electric energy is conducted along a periodically changing direction in a circuit. The power strength of most alternating currents also varies periodically over time. The periodic variation of the alternating current in the direction of conduction is defined by the frequency of the alternating current. When the frequency of the alternating current is higher, the alternating current can change the direction of conduction faster, and when the frequency of the alternating current is lower, the alternating current can change the direction of conduction slowly. Common AC power sources include city power, industrial and agricultural power, and residential power.

(5) Transformation ratio. The "transformation ratio" of the transformer in the embodiment of the present application refers to the ratio between the number of turns of the primary winding of the transformer and the number of turns of the secondary winding. If the transformer performs step-up conversion, the number of turns of the primary winding is smaller than the number of turns of the secondary winding. If the transformer performs step-down conversion, the number of turns of the primary winding is greater than the number of turns of the secondary winding. The "transformation ratio" of the inverter circuit and the rectifier circuit in the embodiment of the present application refers to the ratio between the voltage amplitude of the output voltage of the inverter circuit and the rectifier circuit and the voltage amplitude of the input voltage.

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. The solutions provided in the embodiments of the present application are applied to devices that need to convert the output voltage of the power supply, where the devices include but are not limited to: vehicles, robots, lighting equipment, industrial equipment, smart factory equipment, and the like. The vehicles provided in the embodiments of the present application may include one or more different types of vehicles or movable objects that operate or move on land (for example, roads, roads, railways, etc.), water surfaces (for example: waterways, rivers, oceans, etc.) or space. For example, vehicles may include vehicles, bicycles, motorcycles, trains, subways, airplanes, boats, aircraft, or other types of transportation or movable objects.

As shown in FIG. 1 , it is a schematic structural diagram of a conversion circuit provided by the embodiment of the present application. The conversion circuit mainly includes an inverter circuit, a rectification circuit, and a transformer connected between the inverter circuit and the rectification circuit for electrical isolation. Wherein, the input end of the inverter circuit is connected to the input end of the conversion circuit, the output end of the inverter circuit is connected to the primary winding of the transformer, the secondary winding of the transformer is connected to the input end of the rectification circuit, and the output end of the rectification circuit is connected to the output end of the conversion circuit, that is, the inverter circuit, the transformer and the rectification circuit are connected in series.

Wherein, the input end of the conversion circuit is connected to the power supply, and the output end of the conversion circuit is connected to the load, that is, the inverter circuit receives the output voltage Vi of the power supply, and the rectification circuit outputs the power supply voltage Vo required by the load. The conversion circuit can convert the voltage output by the power supply to the voltage required by the load to supply power, and supply power to the load.

In the embodiment of the present application, both the inverter circuit and the rectification circuit may have a conversion function. Wherein, the inverter circuit can convert the DC input voltage Vi into an AC voltage, and output the converted AC voltage to the rectifier circuit through the transformer. The rectifier circuit can receive the AC voltage output by the transformer, convert the amplitude of the received AC voltage, and output it to the load through the output terminal of the conversion circuit, thereby supplying power to the load.

Wherein, the rectification circuit may be a Buck circuit with a step-down function, that is, the voltage amplitude of the input voltage of the rectification circuit is higher than the voltage amplitude of the output voltage of the rectification circuit. The rectification circuit may also be a Boost circuit with a boost function, that is, the voltage amplitude of the input voltage of the rectification circuit is smaller than the voltage amplitude of the output voltage of the rectification circuit. The rectification circuit can also be a Buck-Boost circuit with a boost function and a voltage drop function.

In practical applications, the inverter circuit and the rectifier circuit may be half-bridge conversion circuits or full-bridge conversion circuits. Wherein, the circuit structures of the half-bridge conversion circuit and the full-bridge conversion circuit may be the existing circuit structures of the half-bridge conversion circuit and the full-bridge conversion circuit. For example, refer to FIG. 2 , which is a schematic structural diagram of a conversion circuit when both the inverter circuit and the rectification circuit are half-bridge conversion circuits. Referring to FIG. 3 , it is a schematic structural diagram of the conversion circuit when the inverter circuit is a full-bridge conversion circuit and the rectifier circuit is a half-bridge conversion circuit. Among them, Rpri is the internal resistance of the power supply connected to the input end of the conversion circuit, and Rsec is the leakage inductance of the transformer.

The conversion circuits shown in Fig. 2 and Fig. 3 are only for illustration. In practical applications, the inverter circuit and the rectification circuit can also adopt other circuit structures. For example, in order to improve the conversion efficiency of the conversion circuit, the conversion circuit can also include energy storage inductors or capacitors.

When the above-mentioned conversion circuit is used to convert the electric energy output by the power supply, if the input voltage of the conversion circuit changes, the control device connected to the conversion circuit for controlling the operation of the conversion circuit needs to adjust the duty cycle of the conversion circuit according to the change of the input voltage, so as to realize the stable output voltage to the load and ensure the stability of power supply.

Referring to FIG. 4 , it is a control device for a conversion circuit provided by an embodiment of the present application. The control device for a conversion circuit can be connected to the conversion circuit shown above and used to control the operation of the rectification circuit and the inverter circuit. The control device of the conversion circuit includes a compensation circuit and a control circuit.

Wherein, the compensation circuit is used to connect with the inverter circuit and the rectifier circuit; the control circuit is connected to the compensation circuit, and is used to connect to the inverter circuit and the rectifier circuit; the compensation circuit can obtain the first voltage V1 input to the inverter circuit this time and the adjacent one, that is, the input voltage Vi of the conversion circuit, and perform the first compensation on the first voltage V1 obtained this time to obtain the second voltage V2 according to the first difference between the first voltage obtained twice adjacently. According to the parameters of multiple devices in the conversion circuit, the second voltage V2 is compensated for the second time to obtain the third voltage V3. Wherein, the second voltage V2 is a voltage value obtained after sampling delay compensation for the first voltage V1 acquired this time, and the third voltage V3 is a voltage value of the second voltage V2 reaching the rectifier circuit after passing through the inverter circuit and the transformer.

Specifically, since the switches in both the inverter circuit and the rectifier circuit are set with a fixed cycle, the first voltage V1 obtained this time can only be used to adjust the conduction of the switch in the next cycle, resulting in a sampling delay error between the obtained first voltage V1 and the voltage amplitude actually obtained by the inverter circuit. The control circuit can determine the voltage to be converted by the inverter circuit in the next cycle according to the second voltage V2 obtained after sampling delay compensation, and use this voltage to determine the first duty cycle required by the inverter circuit. The control circuit can periodically obtain the fourth voltage V4 output by the rectifier circuit, that is, the output voltage Vo of the conversion circuit, and the second duty cycle value currently required by the rectifier circuit can be determined by the voltage V3 input to the rectifier circuit and the voltage V4 output by the rectifier circuit. Wherein, the sampling period of the first voltage and the fourth voltage may be the same as the conduction period of the switch in the conversion circuit, and the first duty cycle and the second duty cycle constitute the target duty cycle.

In an example, detection devices can be configured in the compensation circuit and the control circuit, the compensation circuit can use the detection device to periodically obtain the first voltage V1 input to the inverter circuit, and the control circuit can use the detection device to regularly obtain the fourth voltage V4 output from the conversion circuit.

In another example, the compensation circuit and the control circuit can also be connected to the detection device, the compensation circuit can use the connected detection device to periodically obtain the first voltage V1 input to the inverter circuit, and the control circuit can use the connected detection device to periodically obtain the fourth voltage V4 output by the conversion circuit. Wherein, the detection device can be arranged in the control device of the conversion circuit, or can be arranged outside the control device of the conversion circuit.

In a possible implementation manner, since the rectifier circuit and the inverter circuit are respectively arranged on the windings on both sides of the transformer, in order to realize the electrical isolation function of the conversion circuit, the control circuit may include a first control unit and a second control unit, and the first control unit may be connected to the inverter circuit to control the conduction of the switch in the inverter circuit. The second control unit can be connected with the rectification circuit, and is used for controlling the conduction of the switch in the rectification circuit.

The working process of the control circuit will be described in detail below in conjunction with the embodiments.

Combined with the foregoing description, the relationship between the input voltage Vi' and the output voltage Vo of the rectifier circuit can satisfy the following formula 1:

Vo=Vi'*D (Formula 1)

Among them, Vi' is the third voltage V3 obtained after the input voltage Vi of the conversion circuit is compensated by the compensation circuit, Vo is the output voltage V4 of the rectification circuit, and D is the second duty cycle of the rectification circuit, which can also be called the transformation ratio of the rectification circuit.

In practical applications, the output voltage Vo of the rectifier circuit may fluctuate. In order to improve the power supply stability of the conversion circuit, as shown in FIG. 4 , the control device of the conversion circuit may further include a digital proportional-integral-differential PID controller. One end of the digital PID controller is connected to the rectifier circuit, and the other end of the digital PID controller is connected to the control circuit for periodically detecting the fourth voltage V4 output by the conversion circuit and outputting the fourth voltage V4 to the control circuit. Among them, the parameters in the digital PID controller can be configured according to the structure of the conversion circuit and the selection of the operator, which will not be described in detail here in this application.

As shown in Figure 1, since the rectifier circuit connected to one end of the digital PID controller is located on the secondary winding side of the transformer, and the control circuit connected to the other end is located on the primary winding side of the transformer, in order to achieve signal isolation on both sides of the transformer, as shown in Figure 5, an isolator is required between the digital PID controller and the rectifier circuit, and the isolator can realize signal isolation between the rectifier circuit and the control device. Wherein, the isolator may be an isolation transformer, or other devices with an isolation function.

Among them, the relationship between the output signal of the digital PID controller and the duty cycle of the rectifier circuit satisfies the following formula 2:

D＝Km*PID_OUT*25/Vi (Formula 2)

Among them, PID_OUT is the output signal of the digital PID controller, that is, the output voltage of the conversion circuit, and Km is the linear coefficient between PID_OUT and the duty cycle D.

In practical applications, since the control device directly acquires the first voltage input to the inverter circuit, the collected input voltage is compensated in a feed-forward manner, that is, the control device of the conversion circuit is arranged on the primary winding side of the transformer. In order to realize the electrical isolation between the primary winding and the secondary winding of the transformer, as shown in Fig. 5, the isolator also needs to be connected between the control circuit and the rectifier circuit, and is used for signal isolation of the signal output by the control circuit for controlling the conduction of the switch in the rectifier circuit. Wherein, the above-mentioned control signal is generated by the control circuit according to the duty ratio calculated by the aforementioned formula 1 and formula 2.

The third voltage received by the aforementioned rectifier circuit is obtained after the second voltage V2 output by the inverter circuit passes through the transformer. The inverter circuit is connected between the power supply and the transformer, and is used to convert the AC voltage output by the power supply into a DC voltage, and is not used for voltage amplitude conversion. Therefore, after receiving the second voltage V2 after sampling delay compensation, the control circuit outputs the second voltage V2 in the form of alternating current.

Specifically, the compensation circuit receives the second voltage compensated by the sampling delay, so as to determine the voltage amplitude actually received by the inverter circuit in the next cycle. Since the inverter circuit does not perform voltage amplitude conversion, the output voltage of the inverter circuit is consistent with the amplitude of the input voltage, thereby determining the duty cycle D1 required by the inverter circuit to convert the above input voltage, and using the above duty cycle D1 to generate a corresponding drive signal and output it to the corresponding switch in the inverter circuit.

The above is the control process of the conversion circuit by the control circuit, and the compensation process of the compensation circuit will be described in detail below in conjunction with the embodiments.

The compensation process of the compensation circuit is mainly divided into dynamic compensation and static compensation. The dynamic compensation is to perform sampling delay compensation on the sampled first voltage V1 to obtain the second voltage V2, so that the amplitude of the second voltage V2 is consistent with the value of the first voltage V1 received by the inverter circuit in the next cycle. The static compensation is that the dynamically compensated second voltage V2 passes through the inverter circuit and the transformer to reach the second voltage V3 generated by the rectifier circuit. The dynamic compensation mainly compensates for the sampling time delay. According to the first difference between the first voltages V1 obtained twice adjacently, the variation in the amplitude of the first voltage V1 within a sampling period can be determined, and the amplitude variation can be used to compensate the first voltage V1 obtained in this sampling to obtain the second voltage V2. The voltage amplitude of the second voltage V2 is the same as the voltage amplitude received by the inverter circuit in the next cycle. The static compensation mainly compensates the fixed voltage difference generated by the second voltage V2 after dynamic compensation reaching the rectifier circuit. The fixed difference can be determined according to the device parameters on the transmission path of the second voltage V2, and the above fixed difference is used to compensate the second voltage V2 after dynamic compensation to obtain the second voltage V3.

The dynamic compensation process and the static compensation process of the compensation circuit are described in detail below.

Dynamic Compensation:

The compensation circuit collects the input voltage Vi of the conversion circuit according to a fixed period, that is, the first voltage V1 input to the inverter circuit. The sampling period can be the update period of the switch duty cycle in the conversion circuit. The input voltage Vi collected can only be used to update the next cycle of the switch duty cycle of the conversion circuit. However, the input voltage is continuously changing between this sampling and the next cycle. Referring to Figure 6, it is the waveform diagram of the amplitude of the input voltage sampled multiple times when the input voltage Vi changes rapidly. It can be seen from Figure 6 that the sampled value of the input voltage Vi presents a step change, that is, the sampled input voltage Vi lags behind the actual change value of the input voltage. Therefore, the change law of the input voltage Vi within a sampling period can be determined according to the first difference between the first voltage acquired twice adjacently, and the second voltage V2 is obtained by dynamically compensating the first voltage V1 sampled this time according to the change law, so that its amplitude is consistent with the actual change of the input voltage in the next cycle. same value.

In an example, the dynamically compensated second voltage may satisfy the following formula three:

V2＝V1(T2)+{V1(T2)-V1(T1)} (Formula 3)

Wherein, V1(T2) is the voltage amplitude of the first voltage V1 acquired this time, and V1(T1) is the voltage amplitude of the first voltage V1 acquired last time. Since the first V1 sampled this time is used to adjust the duty cycle of the next cycle of the conversion circuit, using the above formula 3 to dynamically compensate the first voltage V1 sampled this time can offset the voltage amplitude change caused by the time delay between the sampling of the first voltage V1 sampled this time and the next cycle, so that the volt-second balance can be achieved before and after the change of the input voltage V1. In practical applications, if there is an error between the compensated value and the actual change value, the error may increase after repeated use. In order to ensure accurate compensation, the voltage compensation coefficient Kcomp can also be configured to compensate for the error. The second voltage after dynamic compensation can satisfy the following formula 4:

V2＝V1(T2)+Kcomp*{V1(T2)-V1(T1)} (Formula 4)

Using the above formula 4, the volt-second balance after dynamic compensation can satisfy the formula 5:

Wherein, Ton is the conduction period of the switch in the conversion circuit this time, and T may be the conduction period of the switch in the conversion circuit.

Since the above-mentioned compensation methods in this application are all obtained digital parameters, using the above-mentioned formula five, the digital calculation process of Ton can satisfy the following formula six:

Ton＝PID_OUT*256/V2 (Formula 6)

Using the above formula, in an ideal situation, the voltage compensation coefficient Kcomp can be set to 1, and its volt-second product is a straight line coincident with the X-axis, which means that in an ideal situation, the above-mentioned method is used for dynamic compensation, and the dynamic compensation value is equal to the error value generated by the actual sampling delay, that is, the volt-second balance. Due to fluctuations in the input voltage of the circuit or non-ideal devices, with the use of the circuit, when the voltage compensation coefficient Kcomp is 1, the volt-second product will gradually deviate from the X-axis. In order to ensure accurate compensation, the voltage compensation coefficient Kcomp needs to be adjusted regularly. Referring to Fig. 7, it is the fluctuation interval of the volt-second product when the voltage compensation coefficient Kcomp is set to different values. When the voltage compensation coefficient Kcomp is set to 0, the volt-second product curve can be seen in Fig. 7, which gradually deviates from the X-axis curve, and the sampling error gradually increases. The curves near the X axis are the volt-second product curves when the voltage compensation coefficient Kcomp is set to different values. It can be seen from Figure 7 that even if the volt-second product balance cannot be fully achieved, the value after dynamic compensation is very close to the actual sampling delay error, thus ensuring accurate compensation.

Specifically, 2*t _SW has been experienced from input voltage sampling to feed-forward use and then updating duty cycle, as shown in Figure 8, where HPWM in Figure 8 can be the driving signal waveform corresponding to the high-frequency switch in the conversion circuit, and LPWM can be the driving signal waveform corresponding to the low-frequency switch in the conversion circuit. It can be seen from Figure 8 that 2*t _SW is just a complete cycle of the driving signal required by the switch. Therefore, the driving signal required for the next cycle can be predicted by using the signal of the current cycle. For example, the feedforward calculation of the duty ratio in period N3 is completed in the sampling calculation of period N2, that is, the duty ratio calculation can only use the input voltage Vin2 and Vin1 sampled in period N2 and period N1, but the actual compensated feedforward voltage value that needs to be used should be Vin3, so the calculation relationship of dynamic compensation should satisfy the following formula 7:

Vin3＝Vin2+(Vin2-Vin1)/2t _SW +(2t _SW +2t _D ) (Formula 7)

Specifically, the above method can be used to obtain in advance the second voltage V2 actually required to be converted by the inverter circuit in the next sampling period. After the first control unit obtains the second voltage V2 by using the above dynamic compensation method, since the inverter circuit is not used for voltage amplitude conversion, the second voltage V2 can be used to determine the first duty cycle required by the inverter circuit pair, and use the first duty cycle to generate drive signals for multiple switches in the inverter circuit. In addition, since both the inverter circuit and the first control unit are located at the primary side winding of the transformer, the driving signal can be directly output to the corresponding switch in the inverter circuit, so as to control the operation of the inverter circuit.

Static Compensation:

In practical application, since in the conversion circuit configured with a transformer, the main function of the inverter circuit is to convert the DC voltage Vi input to the conversion circuit into an AC voltage, it does not have the function of voltage amplitude conversion, that is, the voltage amplitude of the input voltage Vi of the conversion circuit is the same as the voltage amplitude output by the first conversion module. Therefore, the voltage drop generated by the input voltage transmitted to the rectifier circuit mainly needs to consider the devices passing through the path from the input voltage Vi to the rectifier circuit after output from the inverter circuit, and corresponding voltage compensation is performed according to device parameters.

Taking the transformer between the inverter circuit and the rectifier circuit as an example, the parameters of multiple devices in the conversion circuit are the transformation ratio and leakage inductance of the transformer. The input voltage Vi of the conversion circuit and the input voltage Vi' of the inverter circuit can satisfy the following formula 8:

Vi'＝Vi*Nps-Vsec (Formula 8)

Among them, Vi is the second voltage V2 obtained after dynamic compensation, Nps is the coil turns ratio between the primary winding and the secondary winding of the transformer, Vsec is the leakage inductance voltage generated by the transformer leakage inductance Rsec, and Vi' is the third voltage V3 obtained after static compensation, which is the actual voltage received by the rectifier circuit in the next switching cycle.

Based on the foregoing, it can be seen that the output voltage Vo1 before the amplitude change of the input voltage Vi satisfies Formula 9, and the output voltage Vo2 after the amplitude change of the input voltage Vi satisfies Formula 10:

Vo1＝(Vi*Nps-Vsec)Km*PID_OUT*25/Vi (Formula 9)

Vo2＝{(Vi+K)*Nps-Vsec}Km*PID_OUT*25/Vi (Formula 10)

Among them, K is the change value of the input voltage Vi, and Vsec is the leakage inductance voltage of the transformer, that is, the voltage drop generated at both ends of the leakage inductance.

It can be seen from Formula 9 and Formula 10 that when the change value K is greater than zero, then (Vi*Nps-Vsec)Km*PID_OUT*25/Vi<{(Vi+K)*Nps-Vsec}Km*PID_OUT*25/Vi, that is, Vo1<Vo2, that is, when the amplitude of the input voltage Vi increases, the output voltage will also increase under the action of static compensation. When the change value K is less than zero, then (Vi*Nps-Vsec)Km*PID_OUT*25/Vi>{(Vi+K)*Nps-Vsec}Km*PID_OUT*25/Vi, that is, Vo1>Vo2, that is, when the amplitude of the input voltage Vi decreases, the output voltage will also decrease under the action of static compensation. That is, there is an amplitude difference between the sampled input voltage Vi and the voltage input to the rectifier circuit, and the value of the amplitude difference can be statically compensated according to the above formula, so that the voltage amplitude after static compensation and dynamic compensation is the same as the actual voltage received by the rectifier circuit.

The third voltage V3 actually received by the rectifier circuit in the next cycle is obtained by using the above dynamic compensation method and the static compensation method, and the fourth voltage V4 output by the rectifier circuit is obtained by using the above digital PID controller. In the case of determining the input voltage V3 and output voltage V4 of the rectifier circuit, the output fourth voltage V4 is divided by the input third voltage V3 using the above formula 1 to determine the transformation ratio required by the rectifier circuit, that is, the second duty cycle required by the rectifier circuit. The second control unit in the control circuit uses the second duty ratio to determine the drive signals of the switches in the rectifier circuit, and sends the drive signals to the corresponding switches, so as to control the output voltage of the rectifier circuit to be stable and improve the power supply stability of the conversion circuit. In addition, since the second control unit is located at the primary winding side of the transformer, and the rectifier circuit is located at the secondary winding side of the transformer, in order to realize signal isolation, the second control unit and the rectifying circuit can be connected through the above-mentioned isolator.

In practical applications, in addition to the above-mentioned transformer for electrical isolation, other devices may be included between the inverter circuit and the rectifier circuit, and the transformation ratio of the above-mentioned transformer may be a fixed value or adjusted by an external device. Therefore, when dynamic compensation is performed, the configuration of the device in the current circuit can be used for compensation. Wherein, the parameters of the device may be stored in advance, or obtained through detection. Based on the same technical idea, the embodiment of the present application also provides a chip, which can be connected to a conversion circuit, and the conversion circuit can include an inverter circuit, a transformer and a rectification circuit. Wherein, the circuit structure of the conversion circuit can be referred to as shown in FIG. 1 to FIG. 3 , which will not be repeated in this application.

Specifically, the chip may include a compensation circuit and a control circuit. The compensation circuit is used for connection with the inverter circuit and the rectification circuit; the control circuit is connected with the compensation circuit for connection with the inverter circuit and the rectification circuit.

Wherein, the compensation circuit is used to periodically obtain the first voltage input to the inverter circuit this time and the adjacent time; according to the first difference between the first voltage obtained twice adjacently, the first voltage obtained this time is compensated to obtain the second voltage; according to the parameters of a plurality of devices in the conversion circuit, the second voltage is compensated to obtain the third voltage; the control circuit is used to obtain the fourth voltage output by the rectifier circuit, determine the target duty cycle according to the fourth voltage obtained this time, the third voltage and the second voltage, and use the target duty cycle to control the conduction of the switches in the rectifier circuit and the inverter circuit.

In actual application, the chip is provided with a plurality of external pins, and the compensation circuit and the control circuit are connected to the multiple pins of the chip. At the same time, the rectifier circuit and the inverter circuit are also connected to the multiple pins of the chip, thereby forming a signal transmission path between the conversion circuit and the chip.

In an example, in order to stabilize the output voltage of the conversion circuit, the chip may further include a digital PID controller, one end of the digital PID controller is connected to the rectification circuit, and the other end of the digital PID controller is connected to the control circuit.

In an example, in order to realize signal isolation between the chip and the conversion circuit, the chip may further include an isolator, which is connected between the control circuit and the rectification circuit, and between the digital PID controller and the rectification circuit.

For the specific structure inside the chip and the working process of each device inside the chip, please refer to the relevant introductions in the aforementioned FIGS. 4 to 8 , which will not be repeated here in this application.

In combination with the above device embodiments, the embodiments of the present application further provide a power converter, which is respectively connected to the power source and the load, and is used to convert the voltage output by the direct power source into the power supply voltage of the load. A power converter may include conversion circuitry and control means.

Wherein, the conversion circuit includes an inverter circuit, a transformer and a rectification circuit; the inverter circuit is used to connect the input end of the conversion circuit to the power supply, and convert the first voltage output by the power supply to a second voltage; the rectification circuit is used to connect the output end of the conversion circuit to the load, and convert the second voltage to the third voltage required for power supply to the load; the control device includes a compensation circuit and a control circuit; the compensation circuit is connected to the rectification circuit and the inverter circuit, and the control circuit is connected to the rectification circuit and the inverter circuit; The first difference between the voltages is obtained by compensating the first voltage obtained this time to obtain a fourth voltage; according to the parameters of multiple devices in the conversion circuit, the fourth voltage is compensated to obtain a fifth voltage; the control circuit is used to obtain the third voltage output by the rectifier circuit, determine the target duty cycle according to the third voltage, the fourth voltage and the fifth voltage obtained this time, and use the target duty cycle to control the conduction of the switches in the rectifier circuit and the inverter circuit.

Wherein, the structure and working mode of the control device and the conversion circuit can be described in the above-mentioned Fig. 1 to Fig. 8, and the present application will not repeat the introduction here.

In an example, the rectification circuit or the inverter circuit in the conversion circuit may be a full-bridge conversion circuit, such as an existing H-bridge rectification circuit, and the rectification circuit and the inverter circuit may also be a half-bridge conversion circuit. The circuit structure in the half-bridge conversion circuit or the full-bridge conversion circuit can be configured according to actual conversion requirements, which is not limited in this application.

In combination with the above device embodiments, the embodiments of the present application also provide a control method for a conversion circuit, which can be applied to the conversion circuits shown in FIG. 1 to FIG. 3 and executed by a control device for the conversion circuit. Specifically, as shown in FIG. 9, the control method of the conversion circuit mainly includes the following steps:

Step 901: Obtain the first voltage input to the inverter circuit this time and the next time. Wherein, the first voltage may be periodically detected by the voltage sensor.

Step 902: Compensate the first voltage acquired this time according to the first difference between the first voltage acquired twice adjacently to obtain a second voltage.

Step 903: Compensate the second voltage to obtain a third voltage according to parameters of multiple devices in the conversion circuit.

Step 904: Obtain the fourth voltage output by the rectifier circuit, determine the target duty cycle according to the obtained fourth voltage, the second voltage and the third voltage, and use the target duty cycle to control the conduction of the switches in the inverter circuit and the rectifier circuit. Wherein, the fourth voltage may be periodically detected by the voltage sensor.

In a possible implementation, according to the parameters of multiple devices in the conversion circuit, if only a transformer for electrical isolation is connected between the inverter circuit and the rectifier circuit, the parameters of the multiple devices in the conversion circuit include the transformation ratio of the transformer and the leakage inductance of the transformer. Compensating the second voltage to obtain the third voltage includes: multiplying the second voltage according to the transformation ratio of the isolation transformer to obtain the fifth voltage; determining the leakage inductance voltage according to the leakage inductance of the isolation transformer. .

In a possible implementation manner, the compensating the first voltage acquired this time to obtain the second voltage according to the first difference between the first voltages obtained twice adjacently includes: performing an addition operation on the first voltage obtained this time according to the first difference to obtain the second voltage.

Specifically, the first difference is the difference between two adjacent obtained first voltages, that is, the magnitude change of the first voltage within one sampling period. Since the first voltage obtained this time can only be used to adjust the duty cycle of the conversion circuit in the next cycle, the first voltage obtained this time can be compensated through the above calculation, so that the voltage amplitude of the second voltage obtained after compensation is the same as the voltage amplitude received by the inverter circuit in the next cycle.

In a possible implementation manner, in order to stabilize the output voltage of the conversion circuit and prevent the output voltage from deviating from an ideal value, when obtaining the fourth voltage output by the second conversion module, a digital proportional-integral-derivative PID controller may be used to periodically obtain the fourth voltage output by the rectification circuit.

In a possible implementation manner, the determining the target duty ratio according to the fourth voltage, the second voltage, and the third voltage acquired this time includes: determining a first duty ratio according to the second voltage, and controlling the conduction of the switch in the first conversion module according to the first duty ratio; controlling the fourth voltage to perform a division operation on the third voltage to obtain a second duty ratio, and controlling the conduction of the switch in the second conversion module according to the second duty ratio. Wherein, the first duty cycle and the second duty cycle constitute the target duty cycle.

Based on the above embodiments, an embodiment of the present application further provides a computer program, which enables the computer to implement the method provided in the embodiment shown in FIG. 9 when the computer program is run on the computer.

Based on the above embodiments, embodiments of the present application also provide a computer-readable storage medium, in which a computer program is stored, and when the computer program is executed by a computer, the computer implements the method provided in the embodiment shown in FIG. 9 . Wherein, the storage medium may be any available medium that can be accessed by a computer. As an example but not limited to: the computer readable medium may include RAM, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM1), CD-ROM or other optical disk storage, magnetic disk storage medium or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer.

The technical solutions provided by the embodiments of the present application may be fully or partially implemented by software, hardware, firmware or any combination thereof. When implemented using software, it may be implemented in whole or in part in the form of a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on the computer, the processes or functions according to the embodiments of the present application will be generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, an access network device, a terminal device or other programmable devices. Computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, computer instructions may be transmitted from one website site, computer, server or data center to another website site, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer, or a data storage device including a server, a data center, and the like integrated with one or more available media. Available media may be magnetic media (eg, floppy disk, hard disk, magnetic tape), optical media (eg, digital video disc (DVD)), or semiconductor media, among others.

The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Anyone familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the application, and all should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims (9)

1. A control device of a conversion circuit connected with the conversion circuit, the conversion circuit including an inverter circuit, a transformer, and a rectifier circuit, the control device of the conversion circuit comprising:

the compensation circuit is used for being connected with the inverter circuit and the rectifying circuit;

the control circuit is connected with the compensation circuit and is used for being connected with the inverter circuit and the rectifying circuit;

the compensation circuit is used for acquiring the first voltage which is input to the inverter circuit at this time and adjacent times; according to a first difference value between the first voltages acquired in two adjacent times, compensating the first voltage acquired at this time to acquire a second voltage; compensating the second voltage according to parameters of a plurality of devices in the conversion circuit to obtain a third voltage;

The control circuit is used for acquiring a fourth voltage output by the rectifying circuit, determining a target duty ratio according to the fourth voltage, the third voltage and the second voltage acquired at this time, and controlling the conduction of the switches in the rectifying circuit and the inverter circuit by utilizing the target duty ratio.

2. The apparatus of claim 1, wherein the compensation circuit comprises: a first compensation unit and a second compensation unit; the parameters of the devices in the conversion circuit comprise the transformation ratio of the transformer and leakage inductance of the transformer:

the first compensation unit is used for acquiring a first voltage which is input to the inverter circuit at this time and adjacent times; according to the first difference value, adding the first voltage acquired at this time to obtain the second voltage;

the second compensation unit is used for multiplying the second voltage according to the transformation ratio of the transformer to obtain a fifth voltage; according to the leakage inductance of the transformer, determining leakage inductance voltage, wherein the leakage inductance voltage is the voltage at two ends of the leakage inductance of the transformer; and subtracting the fifth voltage according to the leakage inductance voltage to obtain the third voltage.

3. The apparatus according to claim 1 or 2, wherein the control device of the conversion circuit further comprises a digital proportional-integral-derivative PID controller, one end of the digital PID controller is connected to the output terminal of the rectifying circuit, and the other end of the digital PID controller is connected to the control circuit, for acquiring the fourth voltage and outputting the fourth voltage to the control circuit.

4. A device according to any one of claims 1 to 3, wherein the control circuit comprises: a first control unit and a second control unit; wherein the first duty cycle and the second duty cycle constitute the target duty cycle:

the first control unit is connected with the compensation circuit and is used for being connected with the inverter circuit, determining a first duty ratio according to the second voltage and controlling the conduction of a switch in the inverter circuit according to the first duty ratio;

the second control unit is connected with the compensation circuit and is used for being connected with the rectification circuit, controlling the fourth voltage to divide the third voltage to obtain a second duty ratio, and controlling the conduction of a switch in the rectification circuit according to the second duty ratio.

5. The apparatus of claim 4, wherein the control means of the conversion circuit further comprises an isolator connected between the digital PID controller and the rectifying circuit, and between the control circuit and the rectifying circuit.

6. A chip connected with a conversion circuit, the conversion circuit including an inverter circuit, a transformer, and a rectifier circuit, comprising:

the compensation circuit is used for being connected with the inverter circuit and the rectifying circuit;

the control circuit is connected with the compensation circuit and is used for being connected with the inverter circuit and the rectifying circuit;

the compensation circuit is used for acquiring the first voltage which is input to the inverter circuit at this time and adjacent times; according to a first difference value between the first voltages acquired in two adjacent times, compensating the first voltage acquired at this time to acquire a second voltage; compensating the second voltage according to parameters of a plurality of devices in the conversion circuit to obtain a third voltage;

the control circuit is used for acquiring a fourth voltage output by the rectifying circuit, determining a target duty ratio according to the fourth voltage, the third voltage and the second voltage acquired at this time, and controlling the conduction of the switches in the rectifying circuit and the inverter circuit by utilizing the target duty ratio.

7. The power converter is characterized by comprising a conversion circuit and a control device;

the conversion circuit comprises an inverter circuit, a transformer and a rectifying circuit; the inverter circuit is used for being connected with a power supply through the input end of the conversion circuit, and converting the first voltage output by the power supply into the second voltage; the rectification circuit is used for being connected with a load through the output end of the conversion circuit, and converting the second voltage into a third voltage required by power supply of the load;

the control device comprises a compensation circuit and a control circuit; the compensation circuit is connected with the rectification circuit and the inverter circuit, and the control circuit is connected with the rectification circuit and the inverter circuit;

the compensation circuit is used for acquiring the first voltage which is input to the inverter circuit at this time and adjacent times; according to a first difference value between the first voltages acquired in two adjacent times, compensating the first voltage acquired at this time to acquire a fourth voltage; compensating the fourth voltage according to parameters of a plurality of devices in the conversion circuit to obtain a fifth voltage;

the control circuit is used for acquiring the third voltage output by the rectifying circuit, determining a target duty ratio according to the third voltage, the fourth voltage and the fifth voltage acquired at this time, and controlling the conduction of the switches in the rectifying circuit and the inverter circuit by utilizing the target duty ratio.

8. The power converter of claim 7, wherein the inverter circuit and the rectifier circuit are half-bridge conversion circuits or full-bridge conversion circuits.

9. A control method of a conversion circuit, applied to conversion circuit connection, the conversion circuit including an inverter circuit, a transformer, and a rectifier circuit, characterized by comprising:

acquiring first voltages input to the inverter circuit at this time and adjacent times;

according to a first difference value between the first voltages acquired in two adjacent times, compensating the first voltage acquired at this time to acquire a second voltage; compensating the second voltage according to parameters of a plurality of devices in the conversion circuit to obtain a third voltage;

and acquiring a fourth voltage output by the rectifying circuit, determining a target duty ratio according to the fourth voltage, the third voltage and the second voltage acquired at the time, and controlling the conduction of the switches in the rectifying circuit and the inverter circuit by using the target duty ratio.