CN113852271B - Current wave-by-wave protection method, device and power conversion device - Google Patents
Current wave-by-wave protection method, device and power conversion device Download PDFInfo
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- CN113852271B CN113852271B CN202010599982.6A CN202010599982A CN113852271B CN 113852271 B CN113852271 B CN 113852271B CN 202010599982 A CN202010599982 A CN 202010599982A CN 113852271 B CN113852271 B CN 113852271B
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/14—Arrangements for reducing ripples from DC input or output
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of DC power input into DC power output
- H02M3/02—Conversion of DC power input into DC power output without intermediate conversion into AC
- H02M3/04—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters
- H02M3/10—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
- H02M3/1584—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load with a plurality of power processing stages connected in parallel
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Abstract
本发明实施例提供了一种电流逐波保护方法、逐波保护保护电路及功率变换装置，该方法包括：对多路交错并联的电源电路中的各路电流进行采样，得到各路电流采样信号；将各路所述电流采样信号通过二极管得到定向电流采样信号，并将所述定向电流采样信号汇总得到电流极值；通过比较器将所述电流极值与预设的参考信号值进行比较，当所述电流极值超出所述参考信号值时，通过所述比较器输出逐波信号以关闭所述多路交错并联电源电路的PWM驱动。通过本发明实施例，解决了相关技术中现有多路交错并联拓扑逐波电路复杂度大、成本高和逐波功能不全面的问题，进而达到以低成本实现多路交错并联拓扑的逐波保护功能的效果。
The embodiment of the present invention provides a current wave-by-wave protection method, a wave-by-wave protection circuit and a power conversion device, the method comprising: sampling each current in a multi-channel interleaved parallel power supply circuit to obtain each current sampling signal; obtaining a directional current sampling signal through a diode for each current sampling signal, and summarizing the directional current sampling signal to obtain a current extreme value; comparing the current extreme value with a preset reference signal value through a comparator, and when the current extreme value exceeds the reference signal value, outputting a wave-by-wave signal through the comparator to turn off the PWM drive of the multi-channel interleaved parallel power supply circuit. Through the embodiment of the present invention, the problems of high complexity, high cost and incomplete wave-by-wave function of the existing multi-channel interleaved parallel topology wave-by-wave circuit in the related art are solved, thereby achieving the effect of realizing the wave-by-wave protection function of the multi-channel interleaved parallel topology at a low cost.
Description
Technical Field
The embodiment of the invention relates to the technical field of power conversion of power supplies, in particular to a current wave-by-wave protection method and device and a power conversion device.
Background
Under the common drive of market demands and technical innovation, switching power supplies are currently being developed towards the targets of high efficiency and high power density. The power density of the power supply is improved, smaller devices can be packaged in the same specification on the device level, and on the other hand, the switching frequency can be improved, so that the size of the magnetic part is reduced. Besides soft switch and new device, the multi-phase staggered parallel connection has become the most common topology structure of the current high-efficiency and high-power density power supply.
The multiple paths of staggered parallel connection can reduce the grades of used components and magnetic pieces so as to improve the efficiency and reduce the input and output ripples. But the multiple interleaved parallel topology means multiple transformers or multiple inductances, and more switching tubes, than the single-path topology. Any path of inductance current is overlarge, and all the drives must be turned off rapidly so as to prevent the power supply from firing caused by damage of components. Thus, wave-by-wave protection of a multi-path interleaved parallel topology becomes particularly complex.
In the existing wave-by-wave protection circuit, the common frequency is that the inductance current is sampled and sent to a comparator to be compared with a given reference value, when the inductance current is larger than the reference value, the comparator is turned over to output a low level, and the low level is sent to a TZ port of the DSP to close all the drivers. If the inductance current is an alternating current quantity, sampling and comparing are needed to be carried out on the positive direction and the negative direction of the inductance current respectively, two wave-by-wave signals corresponding to the positive direction and the negative direction are obtained, and the two wave-by-wave signals are respectively sent into two TZ ports of the DSP, or phase-by-phase protection is carried out on one TZ port of the DSP after phase-by-phase protection. The N-way interleaved parallel topology requires 2N comparison circuits and N TZ ports to implement the complete wave-by-wave protection function, which greatly increases the device cost and complexity of the circuit.
Disclosure of Invention
The embodiment of the invention provides a current wave-by-wave protection method, a current wave-by-wave protection device and a power conversion device, which at least solve the problems of excessive number of devices, excessive cost and excessive circuit complexity required for realizing current wave-by-wave protection in the related technology.
According to one embodiment of the invention, a current wave-by-wave protection method is provided, and the current wave-by-wave protection method comprises the steps of sampling all paths of currents in a multi-path staggered parallel power supply circuit to obtain all paths of current sampling signals, obtaining directional current sampling signals through diodes by all paths of current sampling signals, summarizing the directional current sampling signals to obtain current extremum, comparing the current extremum with a preset reference signal value through a comparator, and outputting a wave-by-wave signal through the comparator to close PWM driving of the multi-path staggered parallel power supply circuit when the current extremum exceeds the reference signal value.
In an exemplary embodiment, the method for obtaining directional current sampling signals by using diodes according to each path of current sampling signals and obtaining current extremum by summarizing the directional current sampling signals may include obtaining positive current sampling signals and negative current sampling signals by using diodes according to each path of current sampling signals, summarizing all positive current sampling signals to obtain positive current maximum values, and summarizing all negative current sampling signals to obtain negative current minimum values.
Further, comparing the current extremum with a preset reference signal value through a comparator, outputting a wave-by-wave signal through the comparator to close PWM driving of the multi-path staggered parallel power supply circuit when the current extremum exceeds the reference signal value, wherein the method comprises the steps of comparing the positive current maximum value and the negative current minimum value with a first reference signal value and a second reference signal value in the comparator respectively, and outputting the wave-by-wave signal through the comparator to close PWM driving of the multi-path staggered parallel power supply circuit when the positive current maximum value is larger than the first reference signal value or the negative current minimum value is smaller than the second reference signal value.
In an exemplary embodiment, when each path of current is an alternating current signal with a frequency greater than a threshold value, each path of current sampling signal is led to obtain a directional current sampling signal through a diode, and the directional current sampling signals are summarized to obtain a current extremum, and the method may include rectifying each path of current sampling signal into a forward current sampling signal respectively, and summarizing each path of forward current sampling signal to obtain a current maximum value.
Further, comparing the current extremum with a preset reference signal value through a comparator, outputting a wave-by-wave signal through the comparator to turn off PWM driving of the multi-path interleaved parallel power supply circuit when the current extremum exceeds the reference signal value, and comparing the current maximum value with a third reference signal value in the comparator, and outputting the wave-by-wave signal through the comparator to turn off PWM driving of the multi-path interleaved parallel power supply circuit when the current maximum value is greater than the third reference signal value.
In an exemplary embodiment, outputting the wave-by-wave signal through the comparator to turn off the PWM driving of the multi-path interleaved parallel power supply circuit may include outputting the wave-by-wave signal through the comparator to a TZ protection port of a DSP, and when the TZ protection port determines that the wave-by-wave signal is received as a low level, the DSP turns off the PWM driving of the multi-path interleaved parallel power supply circuit.
According to another embodiment of the invention, a wave-by-wave protection circuit is provided, which comprises a current sampling circuit, a maximum value selection circuit and a wave-by-wave signal generation circuit which are sequentially connected, wherein the current sampling circuit samples each path of current in a multi-path staggered parallel power supply circuit and outputs each path of current sampling signal respectively, the maximum value selection circuit is connected with the output of a current sampling sub-circuit, the input end of the maximum value selection circuit rectifies each path of current sampling signal into a directional current sampling signal and gathers the directional current sampling signals to obtain a current extremum and outputs the current extremum, the first input end of the wave-by-wave signal generation circuit is connected with the output end of the maximum value selection circuit to input the current extremum, and the second input end of the wave-by-wave signal generation circuit is used for inputting a preset reference signal value, and outputting the wave-by-wave signal to close PWM driving of the multi-path staggered parallel switching power supply circuit under the condition that the current extremum exceeds the reference signal value.
In an exemplary embodiment, the maximum value selection circuit has a plurality of input ends, each input end corresponds to one current sampling signal, each input end is connected with two diodes in parallel so as to filter each input current sampling signal into a positive current sampling signal and a negative current sampling signal, the positive current sampling signals of the sampling signals are summarized and then superimposed with a first bias voltage and connected to a first follower, the first follower outputs a positive current maximum value, the negative current sampling signals of the sampling signals are summarized and then superimposed with a second bias voltage and connected to a second follower, and the second follower outputs a negative current maximum value.
In an exemplary embodiment, the wave-by-wave signal generating circuit includes a first comparator and a second comparator, wherein an inverting input terminal of the first comparator is used for inputting a positive current maximum value output by the maximum value selecting circuit, an in-phase input terminal of the first comparator is used for inputting a preset first reference signal value, when the positive current maximum value is larger than the first reference signal value, the first comparator outputs a wave-by-wave signal at an output terminal, an inverting input terminal of the second comparator is used for inputting a negative current maximum value output by the maximum value selecting circuit, an in-phase input terminal of the second comparator is used for inputting a preset second reference signal value, and when the negative current minimum value is smaller than the second reference signal value, the second comparator outputs a wave-by-wave signal at an output terminal.
In an exemplary embodiment, the maximum value selection circuit includes a plurality of diode rectifier bridges connected in parallel with each other, a bias voltage, and a follower, where the plurality of diode rectifier bridges connected in parallel with each other rectifies each path of current sampling signal into a path of forward current sampling signal, and superimposes the bias voltage and inputs the superimposed forward current sampling signal to the follower, and an output end of the follower outputs a maximum value of forward current in the forward current sampling signal.
In an exemplary embodiment, the wave-by-wave signal generating circuit includes a comparator, an inverting input terminal of the comparator is used for inputting the forward current maximum value output by the maximum value selecting circuit, a non-inverting input terminal of the comparator is used for inputting a preset third reference signal value, and when the current maximum value is greater than the third reference signal value, the comparator is turned over to output the wave-by-wave signal at an output terminal.
In one exemplary embodiment, the sampling circuit is one of a resistance sampling circuit, a hall sensor sampling circuit, and a current transformer sampling circuit.
In one exemplary embodiment, the wave-by-wave protection circuit further comprises a PWM driving circuit, wherein an input end of the PWM driving circuit is connected with an output end of the wave-by-wave signal generation circuit, and a PWM driving signal is generated based on the input low-level wave-by-wave signal.
According to still another embodiment of the present invention, there is provided a power conversion apparatus, which may include a power conversion unit group and a control unit, the control unit being respectively connected to each power conversion unit in the power conversion unit group, the control unit including the above-mentioned step-by-step protection circuit to turn off PWM driving of the power conversion unit in case of an overcurrent of the power conversion unit.
According to the embodiment of the invention, when the directional current sampling signals obtained by the diodes of each current sampling signal exceed the reference signal value, the PWM drive is turned off by the comparator to protect the circuit, so that the problems of high complexity, high cost and incomplete wave-by-wave function of the conventional multi-path staggered parallel topology wave-by-wave circuit in the related art can be solved, and the effect of realizing the wave-by-wave protection function of the multi-path staggered parallel topology at low cost is achieved.
Drawings
FIG. 1 is a flow chart of a current step-by-step protection method according to an embodiment of the present invention;
FIG. 2 is a flow chart of a current bi-directional wave-by-wave protection method according to an embodiment of the invention;
FIG. 3 is a flow chart of a current rectifying, wave-by-wave protection method according to an embodiment of the invention;
FIG. 4 is a block diagram of a current step-by-step protection device according to an embodiment of the present invention;
FIG. 5 is a block diagram of a current step-by-step protection device based on varying drive duty cycle magnitudes in accordance with an embodiment of the present invention;
fig. 6 is a block diagram of a power conversion apparatus according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of a power conversion apparatus according to an alternative embodiment of the present invention;
fig. 8 is a circuit schematic of a power conversion unit according to an alternative embodiment of the invention;
Fig. 9 is a control schematic diagram of a power conversion apparatus according to an alternative embodiment of the present invention;
FIG. 10 is a block diagram of a wave-by-wave protection circuit according to an alternative embodiment of the present invention;
FIG. 11 is a circuit schematic of a current sampling module according to an alternative embodiment of the invention;
FIG. 12 is a circuit schematic of a wave-by-wave protection circuit according to an alternative embodiment of the invention;
Fig. 13 is a waveform diagram of a wave-by-wave protection when a battery is charged according to an alternative embodiment of the present invention;
fig. 14 is a waveform diagram of a wave-by-wave protection when the battery is discharged according to an alternative embodiment of the present invention;
fig. 15 is a control schematic diagram of a power conversion apparatus according to a second alternative embodiment of the present invention;
fig. 16 is a circuit schematic of a power conversion unit according to an alternative embodiment of the present invention;
FIG. 17 is a circuit schematic of a wave-by-wave protection circuit according to an alternative embodiment of the invention;
FIG. 18 is a wave-by-wave guard waveform diagram according to an alternative embodiment of the present invention;
FIG. 19 is a waveform diagram of a wave-by-wave protection function according to an alternative embodiment II of the present invention;
Fig. 20 is a circuit schematic of an inductor current sampling circuit according to an alternative embodiment of the present invention;
Fig. 21 is a circuit schematic of a full-wave rectified wave-by-wave protection circuit in accordance with an alternative embodiment of the invention;
fig. 22 is a waveform diagram of a full-wave rectified wave-by-wave protection circuit in accordance with an alternative embodiment of the present invention;
FIG. 23 is a circuit schematic of a half-wave rectified wave-by-wave protection circuit in accordance with an alternative embodiment of the invention;
fig. 24 is a waveform diagram of a half-wave rectified wave-by-wave protection circuit in accordance with an alternative embodiment of the present invention.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings in conjunction with the embodiments.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order.
In this embodiment, a current step-by-step protection method is provided, fig. 1 is a flowchart of a current step-by-step protection method according to an embodiment of the present invention, and as shown in fig. 1, the flowchart includes the following steps:
Step S101, sampling each path of current in a multi-path staggered parallel power supply circuit to obtain each path of current sampling signal;
step S102, each path of current sampling signal is led to obtain a directional current sampling signal through a diode, and the directional current sampling signals are summarized to obtain a current extremum;
And step S103, comparing the current extremum with a preset reference signal value through a comparator, and outputting a wave-by-wave signal through the comparator to close PWM driving of the multi-path staggered parallel power supply circuit when the current extremum exceeds the reference signal value.
In an exemplary embodiment, outputting the wave-by-wave signal through the comparator to turn off the PWM driving of the multi-path interleaved parallel power supply circuit may include outputting the wave-by-wave signal through the comparator to a TZ protection port of a DSP, and when the TZ protection port determines that the wave-by-wave signal is received as a low level, the DSP turns off the PWM driving of the multi-path interleaved parallel power supply circuit.
Through the steps, when the directional current sampling signals obtained by the diodes of the current sampling signals exceed the reference signal value, the PWM drive is turned off through the comparator to protect the circuit, so that the problems of high complexity, high cost and incomplete wave-by-wave function of the existing multipath staggered parallel topology wave-by-wave circuit in the related technology are solved, and the effect of realizing the wave-by-wave protection function of the multipath staggered parallel topology at low cost is achieved.
In this embodiment, a current bidirectional wave-by-wave protection method is also provided, fig. 2 is a flowchart of the current bidirectional wave-by-wave protection method according to an embodiment of the present invention, and as shown in fig. 2, the flowchart includes the following steps:
step S201, sampling each path of current in the multi-path staggered parallel power supply circuit to obtain each path of current sampling signal;
Step S202, each path of current sampling signal is divided by a diode to obtain a positive current sampling signal and a negative current sampling signal respectively, all positive current sampling signals are summarized to obtain a positive current maximum value, and all negative current sampling signals are summarized to obtain a negative current minimum value;
Step S203, comparing the positive current maximum value and the negative current minimum value with a first reference signal value and a second reference signal value respectively in a comparator;
In step S204, when the maximum value of the positive current is greater than the first reference signal value or the minimum value of the negative current is less than the second reference signal value, a wave-by-wave signal is output by the comparator to turn off the PWM driving of the multi-path interleaved parallel power supply circuit.
In this embodiment, there is further provided a current rectifying and wave-by-wave protecting method, and fig. 3 is a flowchart of the current rectifying and wave-by-wave protecting method according to an embodiment of the present invention, as shown in fig. 3, the flowchart includes the following steps:
Step S301, when each path of current is an alternating current signal with the frequency larger than a threshold value, each path of current in the multi-path staggered parallel power supply circuit is sampled, and each path of current sampling signal is obtained;
Step S302, rectifying each path of current sampling signals into forward current sampling signals respectively, and summarizing each path of forward current sampling signals to obtain a current maximum value;
And step S303, comparing the current maximum value with a third reference signal value in a comparator, and outputting a wave-by-wave signal through the comparator to turn off PWM driving of the multi-path staggered parallel power supply circuit when the current maximum value is larger than the third reference signal value.
From the description of the above embodiments, it will be clear to a person skilled in the art that the method according to the above embodiments may be implemented by means of software plus the necessary general hardware platform, but of course also by means of hardware, but in many cases the former is a preferred embodiment. Based on such understanding, the technical solution of the present invention may be embodied essentially or in a part contributing to the prior art in the form of a software product stored in a storage medium (e.g. ROM/RAM, magnetic disk, optical disk) comprising instructions for causing a terminal device (which may be a mobile phone, a computer, a server, or a network device, etc.) to perform the method according to the embodiments of the present invention.
The embodiment also provides a current wave-by-wave protection device, which is used for realizing the embodiment and the preferred implementation mode, and the description is omitted. As used below, the term "unit" may be a combination of software and/or hardware that implements a predetermined function. While the means described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware, is also possible and contemplated.
Fig. 4 is a block diagram of a current step-by-step protection apparatus according to an embodiment of the present invention, which includes a sampling sub-unit 110 and a step-by-step protection sub-unit 120, as shown in fig. 4.
The sampling subunit 110 is configured to sample each path of current in the multiple paths of power supply circuits that are staggered and connected in parallel, so as to obtain each path of current sampling signal.
The wave-by-wave protection subunit 120 is configured to obtain directional current sampling signals from the current sampling signals through diodes, collect the directional current sampling signals to obtain a current extremum, compare the current extremum with a preset reference signal value through a comparator, and output a wave-by-wave signal through the comparator to turn off PWM driving of the multi-path staggered parallel power supply circuit when the current extremum exceeds the reference signal value.
In an exemplary embodiment, the wave-by-wave protection subunit 120 may be further configured to divide each path of the current sampling signal by a diode to obtain a positive current sampling signal and a negative current sampling signal, aggregate all positive current sampling signals to obtain a positive current maximum value, aggregate all negative current sampling signals to obtain a negative current minimum value, compare the positive current maximum value and the negative current minimum value with a first reference signal value and a second reference signal value in a comparator, and output a wave-by-wave signal to turn off PWM driving of the multi-path interleaved parallel power supply circuit when the positive current maximum value is greater than the first reference signal value or the negative current minimum value is less than the second reference signal value.
In an exemplary embodiment, in the case that each current is an ac signal with a frequency greater than a threshold value, the wave-by-wave protection subunit 120 may be further configured to rectify each current sampling signal into a forward current sampling signal, and aggregate each of the forward current sampling signal signals to obtain a current maximum value, compare the current maximum value with a third reference signal value in a comparator, and output, when the current maximum value is greater than the third reference signal value, a wave-by-wave signal through the comparator to turn off PWM driving of the multi-path interleaved parallel power supply circuit.
In an exemplary embodiment, the sampling subunit 110 may include one of a resistance sampling circuit, a hall sensor sampling circuit, and a current transformer sampling circuit.
Fig. 5 is a block diagram of a current step-by-step protection device based on changing the driving duty ratio according to an embodiment of the present invention, and as shown in fig. 5, the device includes a loop algorithm subunit 130 and a PWM driving subunit 140 in addition to all the modules shown in fig. 4.
The loop algorithm subunit 130 is configured to calculate a driving duty ratio of each power conversion module in the power conversion module group in the multi-path interleaved parallel power supply circuit.
The PWM driving subunit 140 controls the driving duty ratio of each power conversion module based on the wave-by-wave signal to turn off the PWM driving.
It should be noted that each of the above modules may be implemented by software or hardware, and the latter may be implemented by, but not limited to, the above modules all being located in the same processor, or each of the above modules being located in different processors in any combination.
The embodiment of the present invention also provides a power conversion apparatus, and fig. 6 is a block diagram of the power conversion apparatus according to the embodiment of the present invention, and the apparatus includes a power conversion unit group 200 and a control unit 100 as shown in fig. 6.
The control unit 100 is respectively connected to each power conversion unit in the power conversion unit group 200, and the control unit 100 includes any one of the devices in the current step-by-step protection device embodiment, so as to turn off PWM driving of the power conversion unit under the condition that the power conversion unit 200 is over-current.
In an exemplary embodiment, the electronic apparatus may further include a transmission device connected to the power conversion apparatus, and an input/output device connected to the power conversion apparatus.
Specific examples in this embodiment may refer to the examples described in the foregoing embodiments and the exemplary implementation, and this embodiment is not described herein.
In order to facilitate understanding of the technical solutions provided by the present invention, the following details will be described in connection with embodiments of specific scenarios.
The embodiment of the invention provides a current wave-by-wave protection circuit which can be used for multipath staggered parallel topology. The circuit does not need to additionally increase TZ resources of a comparator and a DSP. Only a plurality of diodes are added at the output end of each path of current sampling, and each path of current positive sampling signal and negative sampling signal are taken out and respectively converged to obtain a positive maximum value and a negative minimum value. And comparing the positive maximum value and the negative minimum value with positive and negative reference values through a comparator to obtain positive and negative current wave-by-wave signals, and respectively accessing the positive and negative current wave-by-wave signals into two TZ ports of the DSP. When any one current is overlarge, the wave-by-wave protection signal output by the corresponding positive or negative comparator is turned to be low level, TZ action is triggered, and the DSP immediately turns off all the drivers, so that wave-by-wave protection is realized. Therefore, the N-path staggered parallel topology can realize the wave-by-wave protection function of the whole topology circuit by only needing at most two comparators and two TZ ports. The wave-by-wave protection of the high-frequency resonance current can obtain the maximum value of N paths of current through a full-wave rectification circuit or a half-wave rectification circuit, a wave-by-wave signal is obtained through comparison of a comparator and a set reference value, and a TZ port sent into the DSP is closed and driven timely, so that the wave-by-wave protection is realized. Therefore, the wave-by-wave protection of the N paths of high-frequency resonance currents only needs one comparator and one TZ port.
The embodiment of the invention aims at solving the problems existing in the prior art and provides a current wave-by-wave protection method in a multipath staggered parallel topology. The wave-by-wave protection circuit can realize the comprehensive wave-by-wave protection function of N-path staggered parallel topology without adding excessive devices.
The embodiment of the invention provides a bidirectional conversion power conversion device which comprises a power supply unit, a power conversion unit group, a battery unit and a control unit. The power supply unit comprises a single-phase direct current source, the power conversion unit group comprises two power conversion units, and the battery unit comprises a plurality of Li batteries which are connected in series. The positive and negative of the power supply unit are connected with each power conversion unit at the same time. The output of each power conversion unit is connected in parallel and simultaneously connected to the positive and negative ends of the battery unit. The power supply unit may be used as an input to charge the battery through the power conversion unit set, and the battery unit may also be used as an input to discharge the load through the power conversion unit set in a reverse direction.
The control unit is respectively connected with each power conversion unit, inputs corresponding control signals to each power conversion unit, and controls the on-off time of each power conversion unit tube so that the voltage output by each power conversion unit reaches a target value. The control unit also comprises a wave-by-wave protection circuit to ensure that each power conversion unit can rapidly turn off the drive under the overcurrent condition.
The wave-by-wave protection strategy of the embodiment of the invention adopts the following technical scheme:
And sampling each path of current to obtain a current sampling signal. And each path of current sampling signal is passed through a diode to obtain a positive current sampling signal and a negative current sampling signal. And respectively summarizing positive signals sampled by each path of current to obtain a positive maximum value, and summarizing negative current sampled signals to obtain a negative minimum value. And comparing the positive maximum value and the negative minimum value with respective reference signals through two comparators, wherein when the positive current maximum value is larger than the reference signals, the corresponding comparator outputs a low level, and when the negative current minimum value is smaller than the corresponding reference signals, the corresponding comparator outputs a low level. The outputs of the two comparators are the positive wave-by-wave signal and the negative wave-by-wave signal of the current. And sending the wave-by-wave signals of the positive and negative currents to a TZ protection port of the DSP, and when the TZ protection port receives the wave-by-wave signals to be at a low level, immediately closing PWM driving by the DSP, so that the wave-by-wave protection function is achieved.
The current sampling of each path can be realized through resistance sampling, or can be realized through a Hall sensor or a current transformer. The comparator can be an external independent comparator or an internal comparator of a DSP.
Furthermore, when the current is an alternating current signal with higher frequency, the current sampling signals of each path can be respectively rectified into forward signals, the signals of each path are combined to take the maximum value, and the maximum value is compared with a given reference signal to obtain a final wave-by-wave signal. The number of diodes required for this method is doubled, but only one comparator and TZ port are used, and the wave-by-wave effect is the same as in the above scheme.
The embodiment of the invention comprises a current sampling module, a current sampling signal maximum value selecting module and a wave-by-wave signal generating module. The digital controller used in the present invention includes, but is not limited to, a DSP, and other devices such as a single-chip microcomputer or an ARM may be implemented. The topology applicable to the invention is not limited to two-way staggered parallel bidirectional DC-DC converters, and any multi-way parallel main power loop such as LLC, PFC, PSFB and the like is applicable to the topology comprising a transformer and an inductor.
The embodiment of the invention provides a simple, easy-to-use and low-cost wave-by-wave protection circuit for a power conversion device with multipath staggered parallel topology. The problems that an existing multipath staggered parallel topology wave-by-wave circuit is complex, the cost is high, and the wave-by-wave function is not comprehensive are solved. By adopting the wave-by-wave protection circuit, the wave-by-wave protection function of the N-path staggered parallel topology is comprehensively realized at extremely low cost.
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions in the alternative embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the alternative embodiments of the present invention. Based on the alternative embodiments of the present invention, all other alternative embodiments that a person of ordinary skill in the art could obtain without making any inventive effort fall within the scope of protection of the embodiments of the present invention.
Alternative embodiment one
The bidirectional DC-DC converter specifically refers to the converter having two or more energy ports, and takes a bidirectional energy converter with two ends as an example, wherein one of the two energy ports is an energy input end, the other one is an energy output end, the energy input end and the energy output end can be interchanged, and energy can be bidirectionally transmitted and flowed between the input end and the output end. In order to reduce the current stress of the device and reduce the output ripple, the multi-path staggered parallel topology is widely applied to a bidirectional DC-DC converter.
Fig. 7 is a schematic view of a power conversion apparatus according to a first alternative embodiment of the present invention, and the apparatus includes a power supply unit, a power conversion unit group, a battery unit, and a control unit, as shown in fig. 7. The power supply unit comprises a single-phase direct current source, the power conversion unit group comprises two power conversion units which are connected in parallel in a staggered mode, and the battery unit is formed by connecting a plurality of Li batteries in series. The positive and negative of the power supply unit are connected with each power conversion unit at the same time. The output of each power conversion unit is connected in parallel and simultaneously connected to the positive and negative ends of the battery unit. The power supply unit can be used as input, the battery is charged through the power conversion unit group, and the battery unit can also be used as input, and the power conversion unit group reversely discharges the load with the power supply end connected in parallel.
Fig. 8 is a circuit schematic of a POWER conversion unit according to an alternative embodiment of the present invention, where the POWER conversion unit shown in fig. 8 includes four switching devices Q1, Q2, Q3, Q4, an inductor L1, a capacitor C in, and a capacitor C out, where the drain of the switching device Q1 is connected to the input voltage power+ terminal, the source of the Q1 is simultaneously connected to the first terminal of the inductor L1 and the drain of the Q2, the source of the Q2 is connected to the input POWER-terminal, the second terminal of the inductor L1 is simultaneously connected to the source of the Q3 and the drain of the Q4, the source of the Q4 is connected to the output BAT-terminal, the drain of the Q3 is connected to the bat+ terminal of the output terminal, and the sources of the Q2 and Q4 are simultaneously connected to the output BAT-terminal, and the input POWER-terminal and the output BAT-terminal are in the same network. The two paths of power conversion units are in parallel connection in input and output, and the switching tube drives the staggered 180-degree phase operation, so that the current stress of the tube can be reduced, the loss is reduced, and meanwhile, the output ripple wave can be reduced.
Fig. 9 is a control schematic diagram of a power conversion apparatus according to a first alternative embodiment of the present invention, where the control unit includes a sampling subunit, a loop and algorithm subunit, a wave-by-wave protection subunit, and a PWM driving subunit as shown in fig. 9. In detail, the control unit samples the input voltage, the output voltage, and the inductor current of each power conversion subunit. And calculating the driving duty ratio of each power conversion module through a loop and an algorithm subunit. And driving signals of the switching tubes are obtained through the PWM driving subunit, and the on-off of the MOS tubes in the power conversion subunits are controlled, so that stable target output voltage is obtained. When the inductance current of any path is larger than the reference value i 0, the wave-by-wave protection circuit outputs a low level, triggers the TZ module of the DSP, and immediately turns off all the drivers, thereby realizing the wave-by-wave protection function.
Fig. 10 is a block diagram of a wave-by-wave protection circuit according to an alternative embodiment of the present invention, further, as shown in fig. 10, the implementation of the wave-by-wave protection function includes an M01 current sampling module, an M02 maximum value selecting module, an M03 wave-by-wave signal generating module, and a wave-by-wave function implementing module M04. The wave-by-wave protection function can be realized by TZ-type protection functions of main control chips such as a DSP and the like, and can also be a protection pin of a PWM driving chip.
Specifically, the inductor current sample may be a resistor sample or a hall sensor sample. In this example, the sampling is performed by a hall sensor. Fig. 11 is a circuit schematic of a current sampling module according to a first alternative embodiment of the present invention, as shown in fig. 11, an inductor current flows in from ip+ and flows out from IP-, and a current sampling signal corresponding to the magnitude of the inductor current is obtained at the output terminal VIOUT of the hall chip with reference to VIref. If GND is taken as a reference, an inductor current sampling signal obtained by the VIOUT port is overlapped with a bias voltage of +2.5V. To reduce the sampling error, we differentially sample the current sample signal between VIOUT and VIref. The proportion of the sampling signal is regulated by the signal conditioning unit through the feedback resistor R8 and the input resistors R2 and R4, and the direct-current bias voltage is superposed for the sampling signal through the R5 and the R6, so that both the positive current and the negative current can be acquired without distortion. Wherein R8 = R6, R7 = R5 and, R1 = R2 and the like, r3=r4. The resistor R9 and the capacitor C1 form an RC filter unit for filtering high-frequency interference in the current sampling signal. The relation between the sampled signal and the inductor current is:
wherein IL1 is inductance current, and K is sampling precision of the Hall chip. The obtained current sampling signal IL1_sample is directly sent to the DSP for loop operation. Meanwhile, the IL1_sample and the IL2_sample are also sent into a wave-by-wave protection circuit to generate wave-by-wave signals.
In detail, in the bidirectional DC-DC converter, since energy can flow bi-directionally, the inductor current is bi-directional as well. When the power module charges the battery, the current flows from left to right, the current direction is positive, and when the battery discharges the load, the current flows from right to left, and the direction is negative. Fig. 12 is a circuit schematic of a wave-by-wave protection circuit according to a first alternative embodiment of the present invention, and as shown in fig. 12, the wave-by-wave protection circuit includes a maximum value selection module and a wave-by-wave signal generation module. In the maximum value selection moduleThe value of (2) is equal to the DC bias voltage in the inductor current sampling circuit. When the battery is charged, the induction current sampling signals IL1_sample are combined with induction current signals IL2_sample of the other paths through R1, VD2 and R4 and R6 to obtain the maximum value of the induction current sampling signals IL 1_sample. The positive maximum value is transmitted to a wave-by-wave signal generating module after passing through a voltage follower and an RC filter circuit to obtain IL_P_COMP. The wave-by-wave signal generating module is composed of a comparator which can be built by an external discrete element or can be a DSP internal integrated comparator. The reference voltage Vref_P is set at the non-inverting input of the comparator. Normally, the maximum value il_p_comp of the forward inductor current is smaller than the reference voltage vref_p, and the comparator output tz_p is high. Fig. 13 is a waveform diagram of a step-by-step protection during battery charging according to an alternative embodiment of the present invention, as shown in fig. 13, when the inductor current is excessive in an abnormal situation, il_p_comp is greater than vref_p, and the comparator output tz_p is inverted to a low level. Tz_p is a forward inductor current step-by-step protection signal when the battery is charged, and the signal is connected to the TZ port of the DSP. When TZ_P is low, the DSP immediately turns off all the drives, and when TZ_P is high, the drives are also restored, so that wave-by-wave protection is realized.
Fig. 14 is a waveform diagram of wave-by-wave protection during discharging of a battery according to an alternative embodiment of the present invention, as shown in fig. 14, the wave-by-wave protection function during discharging of the battery is similar to that during charging, the inductor current is converged from right to left by il1_sample and il2_sample to obtain negative minimum values through R1, VD1, R3 and R2, VD3 and R5 respectively, and then il_n_comp is obtained through a voltage follower and an RC filter circuit and is sent to the same-direction input terminal of the comparator. The inverting input of the comparator is given a reference voltage vref_n. Normally il_n_comp is greater than vref_n and the comparator output tz_n is high. Under abnormal conditions, when the inductance current is overlarge, IL_N_COMP is smaller than Vref_N, the comparator outputs TZ_N to be low level, and the DSP is triggered to close all the drives, so that the wave-by-wave protection function is realized.
By the method, only two diodes are added in each wave-by-wave circuit to separate the positive inductance current sampling signal from the negative inductance current sampling signal. All positive current signals take the maximum value, and all negative current signals take the minimum value, so that positive progressive signals and negative progressive signals are obtained through the comparator respectively. And then respectively sending the signals to TZ ports of the DSP, and immediately closing all the drivers when any one of the wave-gradual signals is negative, thereby realizing the wave-gradual protection function of each path of inductance current. The whole wave-by-wave protection circuit can realize wave-by-wave protection of N-path staggered parallel topology by only needing two comparators, two TZ ports and 2N diodes.
The controller in the above technical scheme includes, but is not limited to, a single chip microcomputer, a DSP, an ARM, and the like. The wave-by-wave mode is not limited to the immediately resume drive after the wave-by-wave signal disappears, and may be set to resume drive after the wave-by-wave low level signal disappears for one or more switching cycles as needed. The implementation of the wave-by-wave protection is not limited to the TZ function closing drive of the DSP, and the closing and the recovery of the PWM drive can be realized by directly controlling other modes such as each driving chip by the wave-by-wave signal. The technical scheme can be used for, but not limited to, a two-way staggered parallel bidirectional DC-DC device, and also used for wave-by-wave protection of any multipath staggered topology.
Alternative embodiment II
The power portion of this embodiment is a three-phase high power combined topology. Fig. 15 is a control schematic diagram of a power conversion apparatus according to a second alternative embodiment of the present invention, and as shown in fig. 15, the apparatus mainly includes a power supply unit, an inductance unit, a power conversion unit group, a BUS capacitor, and a control unit. The power supply unit comprises a three-phase alternating current source, the three inductance units are formed by inductances, charge and discharge of the power circuit are achieved, and the power conversion unit group comprises three power conversion units. The three-phase output of the power supply unit is respectively connected with the three inductance units in series, one end input of each power conversion unit is connected with the corresponding inductance unit, and the other ends are connected together in a star shape. The output of each power conversion unit is connected with a BUS capacitor. The output BUS voltage of each power conversion unit is used as the power conversion result of the power conversion device.
Fig. 16 is a circuit schematic diagram of a power conversion unit according to a second alternative embodiment of the present invention, where, as shown in fig. 16, Q1 and Q2 are two power MOS transistors, which are high-frequency switching transistors, and driving PWM1 and PWM2 is calculated by a control unit, and the on-off time of the MOS transistors is controlled by controlling the magnitude of the PWM driving duty ratio, so as to control the magnitude of the voltage of the BUS capacitor C1. VT1 and VT2 are power frequency return pipes, including but not limited to power diodes, and power switch tubes such as MOS tubes can also be used. The midpoint COM of the high-frequency MOS tube is connected with the boost inductor, and the midpoint N of the power frequency diode is connected with N points of other power units to form star connection.
The control unit samples the input line voltage, the three inductance currents and the BUS voltage, and the control signals of the power conversion modules are obtained through loop control calculation, so that the stable BUS voltage is obtained. In detail, the control unit includes a sampling subunit, a loop algorithm subunit, a wave-by-wave protection subunit, and a PWM driving subunit.
Specifically, the sampling subunit samples line voltage of the three-phase power supply, inductance current of the three-phase inductor and BUS voltage of the three-phase BUS through a signal conditioning circuit such as an operational amplifier and the like, and sends the sampled analog quantity to an ADC port of the main control chip DSP. Furthermore, an analog-to-digital conversion subunit in the DSP converts the sampled analog signals into digital signals, restores actual voltage and current values and participates in calculation of loops and algorithm subunits. And obtaining PWM driving signals of the power switches of each phase, thereby controlling the on and off of the power switches and realizing accurate output of BUS voltage. When the circuit is abnormal and the three-phase inductance current is too high, the wave-by-wave protection subunit generates a low-level wave-by-wave signal, rapidly triggers the DSP to turn off PWM driving, and returns to driving after the wave-by-wave signal disappears, so that the wave-by-wave protection function of the three-phase high-power PFC is realized.
The inductance current in the three-phase combined conversion topology is a 50HZ power frequency alternating current signal, and the signal sampling circuit is the same as the first embodiment and adopts a Hall chip for sampling. Further, fig. 17 is a schematic circuit diagram of a wave-by-wave protection circuit according to a second alternative embodiment of the present invention, and the wave-by-wave protection circuit in the present device is shown in fig. 17. Fig. 18 is a waveform diagram of a step-by-step protection circuit according to a second alternative embodiment of the present invention, and a circuit waveform corresponding to the step-by-step protection circuit in the present apparatus is shown in fig. 18. The three-phase inductor current signals Ia_sample, ib_sample and ic_sample obtain maximum current signals of positive and negative half cycles through a maximum value selection module. IL_P_COMP and IL_N_COMP are obtained through a voltage follower and an RC filter circuit, as shown in FIG. 12. The maximum current signal of positive and negative half cycles enters a wave-by-wave signal generating module, and a positive half cycle wave-by-wave signal TZ_P and a negative half cycle wave-by-wave signal TZ_N are obtained through comparison with a set reference voltage Vref_ P, vref _N.
Specifically, fig. 19 is a waveform diagram of a wave-by-wave protection function according to a second alternative embodiment of the present invention, as shown in fig. 19, in a normal operation situation, the maximum inductor current sampling signal il_p_comp of the positive half cycle is smaller than the reference signal vref_p, and the corresponding positive half cycle wave-by-wave signal tz_p is at a high level. When the positive half-cycle inductor current of any phase is too large, il_p_comp is larger than the reference signal vref_p, so that the positive half-cycle wave-by-wave signal tz_p output by the comparator is inverted to a low level. Similarly, under normal operation, the maximum inductor current sampling signal il_n_comp of the negative half cycle is greater than the reference signal vref_n, and the corresponding negative half cycle wave-by-wave signal tz_n is at a high level. When the negative half-cycle inductor current of any phase is too large, il_n_comp is smaller than the reference signal vref_n, so that the negative half-cycle wave-by-wave signal tz_n output by the comparator is inverted to a low level. Any path of positive half cycle wave-by-wave signal TZ_P and negative half cycle wave-by-wave signal TZ_N is low level, so that a TZ module of the DSP is triggered to immediately close all driving, and the driving is restored after all wave-by-wave signals are overturned to high level. All the wave-by-wave signals can be set to disappear for one or more switching periods according to the requirement, and then the driving is resumed.
By the method, the step-by-step protection function of the three-phase PFC power frequency inductance current is realized by only two comparators and two TZ ports. The circuit is simple, the cost is low, and the wave-by-wave protection is comprehensive and timely. The controller in the above technical scheme includes, but is not limited to, a single chip microcomputer, a DSP, an ARM, and the like. The wave-by-wave protection mode is not limited to TZ function closing driving of the DSP, and PWM driving closing and recovering can be realized by directly controlling other modes such as each driving chip through wave-by-wave signals.
Alternative embodiment III
This embodiment is directed to a topology where the inductor current is a high frequency resonant current. Taking two-way interleaved 180-degree parallel LLC topology as an example, the frequency of resonant inductor current is the same as the switching frequency. Fig. 20 is a circuit schematic of an inductor current sampling circuit according to a third alternative embodiment of the present invention, as shown in fig. 20, in which an inductor current sampling signal is obtained by adding an auxiliary winding to a resonant inductor. The amplitude of the current sampling signal can be changed by changing the turn ratio of the inductor to the auxiliary winding.
Further, fig. 21 is a schematic circuit diagram of a full-wave rectifying and wave-shaping protection circuit according to an alternative embodiment of the present invention, and fig. 22 is a waveform diagram of a full-wave rectifying and wave-shaping protection circuit according to an alternative embodiment of the present invention, where, as shown in fig. 21 and 22, each path of inductor current sampling signal is full-wave rectified by a rectifying bridge formed by four diodes, respectively. And the IL1 sample+ and the IL1 Sample charge the capacitor C1 through a rectifier bridge formed by VD 1-VD 4, and rectify a negative signal of a current sampling signal of the inductor L1 to a positive signal. The same is done for the current sample signal of inductor IL 2. And finally, connecting the two paths of rectified signals together to obtain a maximum current signal of the two paths of inductor current after rectification, and obtaining the maximum value IL_COMP of each path of inductor current sampling signal through an RC filter circuit formed by R5 and C3 and a clamping diode formed by VD9 and VD 10. Il_comp is fed to the inverting input of the comparator, where the reference signal Vref is given. In normal operation, il_comp is less than the reference signal Vref, and the comparator output tz_sum is high. When the converter works abnormally and any path of inductor current is too high, the maximum value IL_COMP of an inductor current sampling signal is larger than a reference value Vref, the output TZ_sum of the comparator is turned to be low level, the DSP is triggered to immediately close the drive, and the device is prevented from being damaged due to overcurrent, so that the wave-by-wave protection function is realized. In the figure, the driving of the wave-by-wave protection for closing 3 switching periods is set, and the wave-by-wave protection time can be set according to the requirement.
For the topology that the inductance current is the high-frequency resonance current, another wave-by-wave protection circuit is also provided in the embodiment. Fig. 23 is a schematic circuit diagram of a half-wave rectifying and wave-shaping protection circuit according to an alternative embodiment of the present invention, and fig. 24 is a waveform diagram of a half-wave rectifying and wave-shaping protection circuit according to an alternative embodiment of the present invention, as shown in fig. 23 and 24, in which the inductor current of L1 charges the capacitor C1 through the auxiliary winding, and then obtains the inductor current signal of the positive half cycle through the diode VD 1. The other path is also the sampling signal of the positive half cycle obtained by the same way. The positive half cycle of the two paths of signals takes the maximum value, and the maximum signal IL_COMP of the positive half cycle of the two paths of inductive currents is obtained through an RC filter circuit formed by R7 and C3 and a clamping circuit formed by VD3 and VD 4. Similarly, the signal is fed to the inverting input of the comparator, where the reference signal Vref is provided. In normal operation, il_comp is less than the reference signal Vref, and the comparator output tz_sum is high. When the converter works abnormally and any path of inductor current is too high, the maximum value IL_COMP of an inductor current sampling signal is larger than a reference value Vref, the output TZ_sum of the comparator is turned to be low level, the DSP is triggered to immediately close the drive, and the device is prevented from being damaged due to overcurrent, so that the wave-by-wave protection function is realized. In the figure, the driving of the wave-by-wave protection for closing 3 switching periods is set, and the wave-by-wave protection time can be set according to the requirement.
In the above embodiment, only one comparator and one TZ port are needed to realize the wave-by-wave protection function of the multipath high-frequency resonant inductor current, thereby simplifying the complexity of the structure of the existing wave-by-wave protection circuit and reducing the circuit cost.
It should be noted that, the controller in the above technical scheme includes, but is not limited to, a single chip microcomputer, a DSP, an ARM, and the like. The wave-by-wave protection mode is not limited to TZ function closing driving of the DSP, and PWM driving closing and recovering can be realized by directly controlling other modes such as each driving chip through wave-by-wave signals. The scheme is not limited to LLC resonance topology, and any single-path or multi-path staggered parallel topology in which current is in a high-frequency alternating current state is applicable.
It will be appreciated by those skilled in the art that the modules or steps of the invention described above may be implemented in a general purpose computing device, they may be concentrated on a single computing device, or distributed across a network of computing devices, they may be implemented in program code executable by computing devices, so that they may be stored in a storage device for execution by computing devices, and in some cases, the steps shown or described may be performed in a different order than that shown or described herein, or they may be separately fabricated into individual integrated circuit modules, or multiple modules or steps of them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1.A current step-by-step protection method, comprising:
Sampling each path of current in the multipath staggered parallel power supply circuit to obtain each path of current sampling signal;
Each path of current sampling signals is respectively led to obtain directional current sampling signals through diodes, and the directional current sampling signals are summarized to obtain a current extremum;
Comparing the current extremum with a preset reference signal value through a comparator, and outputting a wave-by-wave signal through the comparator to close PWM driving of the multi-path staggered parallel power supply circuit when the current extremum exceeds the reference signal value;
Each path of current sampling signals is led to obtain directional current sampling signals through diodes, and the directional current sampling signals are summarized to obtain current extremum, and the method comprises the following steps:
each path of current sampling signal is divided by a diode to obtain a positive current sampling signal and a negative current sampling signal respectively, all positive current sampling signals are summarized to obtain a positive current maximum value, and all negative current sampling signals are summarized to obtain a negative current minimum value;
Or alternatively
When each path of current is an alternating current signal with the frequency larger than a threshold value, each path of current sampling signal is led to obtain a directional current sampling signal through a diode, and the directional current sampling signals are summarized to obtain a current extremum, and the method comprises the following steps:
and rectifying each path of current sampling signals into forward current sampling signals respectively, and summarizing each path of forward current sampling signals to obtain a current maximum value.
2. The method of claim 1, wherein comparing the current extremum with a preset reference signal value by a comparator, and outputting a wave-by-wave signal by the comparator to turn off PWM driving of the multi-path interleaved parallel power supply circuit when the current extremum exceeds the reference signal value, comprises:
comparing the positive current maximum value and the negative current minimum value with a first reference signal value and a second reference signal value respectively in a comparator;
And when the maximum value of the positive current is larger than the first reference signal value or the minimum value of the negative current is smaller than the second reference signal value, outputting a wave-by-wave signal through the comparator to turn off PWM driving of the multi-path staggered parallel power supply circuit.
3. The method of claim 1, wherein comparing the current extremum with a preset reference signal value by a comparator, and outputting a wave-by-wave signal by the comparator to turn off PWM driving of the multi-path interleaved parallel power supply circuit when the current extremum exceeds the reference signal value, comprises:
and comparing the current maximum value with a third reference signal value in a comparator, and outputting a wave-by-wave signal through the comparator to turn off PWM driving of the multi-path staggered parallel power supply circuit when the current maximum value is larger than the third reference signal value.
4. The method of claim 1, wherein outputting a wave-by-wave signal by the comparator to turn off PWM driving of the multi-path interleaved parallel power supply circuit comprises:
outputting a wave-by-wave signal to a TZ protection port of the DSP through the comparator;
and when the TZ protection port judges that the received wave-by-wave signal is at a low level, the DSP turns off PWM driving of the multipath staggered parallel power supply circuit.
5. A wave-by-wave protection circuit is characterized by comprising a current sampling circuit, a maximum value selection circuit and a wave-by-wave signal generation circuit which are connected in sequence, wherein
The current sampling circuit samples all paths of currents in the multipath staggered parallel power supply circuit and outputs all paths of current sampling signals respectively;
The input end of the maximum value selection circuit is connected with the output end of the current sampling sub-circuit, each path of current sampling signal is rectified or filtered into a directional current sampling signal, the directional current sampling signals are summarized to obtain a current extremum, and the current extremum is output;
The first input end of the wave-by-wave signal generating circuit is connected with the output end of the maximum value selecting circuit so as to input the current extremum, the second input end of the wave-by-wave signal generating circuit is used for inputting a preset reference signal value, and under the condition that the current extremum exceeds the reference signal value, a wave-by-wave signal is output so as to close PWM driving of the multipath staggered parallel switching power supply circuit;
The maximum value selection circuit is provided with a plurality of input ends, each input end corresponds to one path of current sampling signal, each input end is connected with two diodes in parallel so as to filter each path of input sampling signal into a positive current sampling signal and a negative current sampling signal, the positive current sampling signals of all paths of sampling signals are summarized and then superimposed with a first bias voltage and are connected to a first follower, the first follower outputs a positive current maximum value, the negative current sampling signals of all paths of sampling signals are summarized and then superimposed with a second bias voltage and are connected to a second follower, and the second follower outputs a negative current maximum value;
Or alternatively
The maximum value selection circuit comprises a plurality of diode rectifier bridges connected in parallel, bias voltage and a follower, wherein the plurality of diode rectifier bridges connected in parallel rectify each path of current sampling signals into a path of forward current sampling signals, the bias voltage is superimposed and then input to the follower, and the output end of the follower outputs the maximum value of forward current in the forward current sampling signals.
6. The wave-by-wave protection circuit of claim 5, wherein the wave-by-wave signal generation circuit comprises a first comparator and a second comparator, wherein,
The inverting input end of the first comparator is used for inputting the maximum value of the forward current output by the maximum value selection circuit, the non-inverting input end of the first comparator is used for inputting a preset first reference signal value, and when the maximum value of the forward current is larger than the first reference signal value, the first comparator turns over and outputs a wave-by-wave signal at the output end;
The inverting input end of the second comparator is used for inputting the negative current maximum value output by the maximum value selection circuit, the non-inverting input end of the second comparator is used for inputting a preset second reference signal value, and when the negative current minimum value is smaller than the second reference signal value, the second comparator turns over to output a wave-by-wave signal at the output end.
7. The wave-by-wave protection circuit according to claim 5, wherein the wave-by-wave signal generation circuit comprises a comparator having an inverting input for inputting the maximum value of the forward current outputted by the maximum value selection circuit, and having a non-inverting input for inputting a predetermined third reference signal value, the comparator being flipped to output the wave-by-wave signal at an output when the maximum value of the current is greater than the third reference signal value.
8. The wave-by-wave protection circuit according to claim 5, wherein the sampling circuit is one of a resistance sampling circuit, a Hall sensor sampling circuit, and a current transformer sampling circuit.
9. The wave-by-wave protection circuit of claim 5, further comprising:
And the input end of the PWM driving circuit is connected with the output end of the wave-by-wave signal generating circuit, and the PWM driving signal is generated based on the input low-level wave-by-wave signal.
10. The power conversion device is characterized by comprising a power conversion unit group and a control unit, wherein the control unit is respectively connected with each power conversion unit in the power conversion unit group, and comprises the wave-by-wave protection circuit as claimed in any one of claims 5-9, so that in the case of overcurrent of the power conversion units, the driving duty ratio of each power conversion module is controlled by outputting a PWM driving signal to turn off PWM driving of the power conversion unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010599982.6A CN113852271B (en) | 2020-06-28 | 2020-06-28 | Current wave-by-wave protection method, device and power conversion device |
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| CN115566881A (en) * | 2022-10-25 | 2023-01-03 | 骏盈半导体(上海)有限公司 | Control circuit, control method and switching power supply of multi-phase DC-DC converter |
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| US9357598B2 (en) * | 2010-12-09 | 2016-05-31 | Indice Semiconductor Inc. | Power supply control system and device |
| DE102011087496A1 (en) * | 2011-11-30 | 2013-06-27 | H-Tech Ag | Method and device for charging rechargeable cells |
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