Current wave-by-wave protection method, device and power conversion device

Abstract

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

[0001] The embodiments of the present invention relate to the technical field of power conversion of power supplies, and in particular to a current wave-by-wave protection method, device and power conversion device. Background Art

[0002] Driven by market demand and technological innovation, switching power supplies are currently developing towards the goal of high efficiency and high power density. To improve the power density of the power supply, smaller devices with the same specifications can be selected at the device level, and the switching frequency can be increased to reduce the volume of magnetic parts. In addition to using soft switches and new devices to improve the conversion efficiency of the power supply, multi-phase interleaved parallel connection has become the most commonly used topology for high-efficiency and high-power density power supplies.

[0003] Multi-channel interleaved parallel connection can reduce the level of components and magnetic parts used to improve efficiency, while reducing input and output ripple. However, compared with the single-channel topology, the multi-channel interleaved parallel topology means multiple transformers or multiple inductors, as well as more switch tubes. If the inductor current of any channel is too large, all drivers must be quickly turned off to prevent component damage and power supply fire. Therefore, the wave-by-wave protection of the multi-channel interleaved parallel topology becomes particularly complicated.

[0004] In the existing wave-by-wave protection circuit, it is more common to sample the inductor current, send it to the comparator, and compare it with a given reference value. When the inductor current is greater than the reference, the comparator flips and outputs a low level, which is sent to the TZ* port of the DSP to turn off all drivers. If the inductor current is an AC quantity, it is necessary to sample and compare the positive and negative directions of the inductor current respectively, and obtain two wave-by-wave signals corresponding to the positive and negative directions, which are sent to the two TZ* ports of the DSP respectively, or sent to one TZ* port of the DSP after ANDing for wave-by-wave protection. The N-way staggered parallel topology requires 2N comparison circuits and N TZ* ports to realize the complete wave-by-wave protection function, which will greatly increase the device cost and circuit complexity. Summary of the invention

[0005] The embodiments of the present invention provide a current wave-by-wave protection method, device and power conversion device to at least solve the problems in the related art of too many components, too high cost and too high circuit complexity required to implement current wave-by-wave protection.

[0006] According to one embodiment of the present invention, a current wave-by-wave protection method is provided, comprising: sampling each current in a multi-channel interlaced 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 aggregating the directional current sampling signals 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 shut down the PWM drive of the multi-channel interlaced parallel power supply circuit.

[0007] In an exemplary embodiment, each current sampling signal is passed through a diode to obtain a directional current sampling signal, and the directional current sampling signals are aggregated to obtain a current extreme value, which may include: each current sampling signal is shunted through a diode to obtain a forward current sampling signal and a negative current sampling signal, respectively, all the forward current sampling signals are aggregated to obtain a maximum forward current value, and all the negative current sampling signals are aggregated to obtain a minimum negative current value.

[0008] Further, the current extreme value is compared with a preset reference signal value through a comparator, and when the current extreme value exceeds the reference signal value, a wave-by-wave signal is output through the comparator to turn off the PWM drive of the multi-way interleaved parallel power supply circuit, which may include: comparing the maximum forward current value and the minimum negative current value with a first reference signal value and a second reference signal value, respectively, in the comparator; when the maximum forward current value is greater than the first reference signal value, or the minimum negative current value is less than the second reference signal value, a wave-by-wave signal is output through the comparator to turn off the PWM drive of the multi-way interleaved parallel power supply circuit.

[0009] In an exemplary embodiment, when each current is an AC signal with a frequency greater than a threshold, each current sampling signal is passed through a diode to obtain a directional current sampling signal, and the directional current sampling signal is aggregated to obtain a current extreme value, which may include: rectifying each current sampling signal into a forward current sampling signal, and aggregating the forward current sampling signal signals to obtain a current maximum value.

[0010] Further, the current extreme value is compared with a preset reference signal value through a comparator, and when the current extreme value exceeds the reference signal value, a wave-by-wave signal is output through the comparator to turn off the PWM drive of the multi-way interleaved parallel power supply circuit. This may include: comparing the current maximum value with a third reference signal value in the comparator, and when the current maximum value is greater than the third reference signal value, a wave-by-wave signal is output through the comparator to turn off the PWM drive of the multi-way interleaved parallel power supply circuit.

[0011] In an exemplary embodiment, outputting a wave-by-wave signal through the comparator to shut down the PWM drive of the multi-way interleaved parallel power supply circuit may include: outputting a wave-by-wave signal to a TZ* protection port of a DSP through the comparator; when the TZ* protection port determines that the received wave-by-wave signal is at a low level, the DSP shuts down the PWM drive of the multi-way interleaved parallel power supply circuit.

[0012] According to another embodiment of the present invention, a wave-by-wave protection circuit is provided, which includes a current sampling circuit, a maximum value selection circuit and a wave-by-wave signal generating circuit connected in sequence, wherein the current sampling circuit samples each current in a multi-channel staggered parallel power supply circuit and outputs each current sampling signal respectively; the maximum value selection circuit, whose input end is connected to the output of the current sampling subcircuit, rectifies each current sampling signal into a directional current sampling signal, and aggregates the directional current sampling signals to obtain a current extreme value, and outputs the current extreme value; the wave-by-wave signal generating circuit, whose first input end is connected to the output end of the maximum value selection circuit to input the current extreme value, and whose second input end is used to input a preset reference signal value, and outputs a wave-by-wave signal to shut down the PWM drive of the multi-channel staggered parallel switch power supply circuit when the current extreme value exceeds the reference signal value.

[0013] In an exemplary embodiment, the maximum value selection circuit has multiple input terminals, each input terminal corresponds to a current sampling signal, and each input terminal is connected to two diodes in parallel to filter each input sampling signal into a positive current sampling signal and a negative current sampling signal. The positive current sampling signals of each sampling signal are aggregated and superimposed with a first bias voltage and connected to a first follower. The first follower outputs the maximum positive current. The negative current sampling signals of each sampling signal are aggregated and superimposed with a second bias voltage and connected to a second follower. The second follower outputs the maximum negative current.

[0014] In an exemplary embodiment, the wave-by-wave signal generating circuit includes a first comparator and a second comparator, wherein the inverting input terminal of the first comparator is used to input the maximum forward current value output by the maximum value selection circuit, and the non-inverting input terminal of the first comparator is used to input a preset first reference signal value. When the maximum forward current value is greater than the first reference signal value, the first comparator flips and outputs a wave-by-wave signal at the output terminal; the inverting input terminal of the second comparator is used to input the maximum negative current value output by the maximum value selection circuit, and the non-inverting input terminal of the second comparator is used to input a preset second reference signal value. When the minimum negative current value is less than the second reference signal value, the second comparator flips and outputs a wave-by-wave signal at the output terminal.

[0015] In an exemplary embodiment, the maximum value selection circuit includes a plurality of diode rectifier bridges connected in parallel, a bias voltage and a follower connected in sequence, wherein the plurality of diode rectifier bridges connected in parallel rectify each current sampling signal into a forward current sampling signal, and superimpose the bias voltage before inputting it into the follower, and the output end of the follower outputs the maximum forward current value in the forward current sampling signal.

[0016] In an exemplary embodiment, the wave-by-wave signal generating circuit includes a comparator, the inverting input terminal of the comparator is used to input the maximum forward current value output by the maximum value selection circuit, and the non-inverting input terminal of the comparator is used to input a preset third reference signal value. When the maximum current value is greater than the third reference signal value, the comparator flips to output the wave-by-wave signal at the output terminal.

[0017] In an exemplary embodiment, the sampling circuit is one of the following: a resistance sampling circuit, a Hall sensor sampling circuit, and a current mutual inductance sampling circuit.

[0018] In an exemplary embodiment, the wave-by-wave protection circuit further includes: a PWM drive circuit, an input end of which is connected to an output end of the wave-by-wave signal generating circuit, and generates a PWM drive signal based on the input low-level wave-by-wave signal.

[0019] According to another embodiment of the present invention, a power conversion device is also provided, which may include: a power conversion unit group and a control unit, wherein the control unit is respectively connected to each power conversion unit in the power conversion unit group, and the control unit includes the above-mentioned wave-by-wave protection circuit to shut down the PWM drive of the power conversion unit when the power conversion unit is overcurrent.

[0020] Through the above-mentioned embodiments of the present invention, when the directional current sampling signals obtained by the diodes of the current sampling signals of each channel exceed the reference signal value, the PWM drive is turned off by the comparator to protect the circuit. Therefore, 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 technology can be solved, and the effect of realizing the wave-by-wave protection function of the multi-channel interleaved parallel topology at a low cost can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flow chart of a current wave-by-wave protection method according to an embodiment of the present invention;

[0022] Figure 2 is a flow chart of a current bidirectional wave-by-wave protection method according to an embodiment of the present invention;

[0023] Figure 3 is a flow chart of a current rectification wave-by-wave protection method according to an embodiment of the present invention;

[0024] Figure 4 is a structural block diagram of a current wave-by-wave protection device according to an embodiment of the present invention;

[0025] Figure 5 is a structural block diagram of a current wave-by-wave protection device based on changing the driving duty cycle according to an embodiment of the present invention;

[0026] Figure 6 is a structural block diagram of a power conversion device according to an embodiment of the present invention;

[0027] Figure 7 is a schematic structural diagram of a power conversion device according to an optional embodiment 1 of the present invention;

[0028] Figure 8 is a circuit diagram of a power conversion unit according to an optional embodiment 1 of the present invention;

[0029] Fig. 9 is a control schematic diagram of a power conversion device according to an optional embodiment 1 of the present invention;

[0030] Fig.10 is a structural block diagram of a wave-by-wave protection circuit according to an optional embodiment 1 of the present invention;

[0031] Fig.11 is a circuit diagram of a current sampling module according to an optional embodiment 1 of the present invention;

[0032] Fig.12 is a circuit diagram of a wave-by-wave protection circuit according to an optional embodiment 1 of the present invention;

[0033] Fig.13 is a wave-by-wave protection waveform diagram of a battery during charging according to an optional embodiment 1 of the present invention;

[0034] Fig.14 is a wave-by-wave protection waveform diagram of a battery during discharge according to an optional embodiment 1 of the present invention;

[0035] Fig.15 is a control schematic diagram of a power conversion device according to optional embodiment 2 of the present invention;

[0036] Fig.16 is a circuit diagram of a power conversion unit according to optional embodiment 2 of the present invention;

[0037] Fig.17 is a circuit diagram of a wave-by-wave protection circuit according to an optional second embodiment of the present invention;

[0038] Fig.18 is a wave-by-wave protection waveform diagram according to optional embodiment 2 of the present invention;

[0039] Fig.19 is a waveform diagram of a wave-by-wave protection function according to optional embodiment 2 of the present invention;

[0040] Fig. 20 is a circuit diagram of an inductor current sampling circuit according to optional embodiment 3 of the present invention;

[0041] Fig.21 is a circuit diagram of a full-wave rectification wave-by-wave protection circuit according to an optional third embodiment of the present invention;

[0042] Fig. 22 is a waveform diagram of a full-wave rectifier wave-by-wave protection circuit according to optional embodiment 3 of the present invention;

[0043] Fig.23 is a circuit diagram of a half-wave rectification wave-by-wave protection circuit according to an optional third embodiment of the present invention;

[0044] Fig.24 4 is a waveform diagram of a half-wave rectification wave-by-wave protection circuit according to optional embodiment 3 of the present invention. DETAILED DESCRIPTION

[0045] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and in combination with the embodiments.

[0046] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0047] In this embodiment, a current wave-by-wave protection method is provided. Figure 1 is a flow chart of a current wave-by-wave protection method according to an embodiment of the present invention. Figure 1 As shown, the process includes the following steps:

[0048] Step S101, sampling each current in a plurality of power supply circuits connected in parallel to obtain a current sampling signal of each current;

[0049] Step S102, obtaining directional current sampling signals by passing the current sampling signals of each channel through a diode, and summing up the directional current sampling signals to obtain a current extreme value;

[0050] Step S103, 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-path staggered parallel power supply circuit.

[0051] In an exemplary embodiment, outputting a wave-by-wave signal through the comparator to shut down the PWM drive of the multi-way interleaved parallel power supply circuit may include: outputting a wave-by-wave signal to a TZ* protection port of a DSP through the comparator; when the TZ* protection port determines that the received wave-by-wave signal is at a low level, the DSP shuts down the PWM drive of the multi-way interleaved parallel power supply circuit.

[0052] Through the above steps, when the directional current sampling signals obtained by the diodes of the current sampling signals of each channel exceed the reference signal value, the PWM drive is turned off by the comparator to protect the circuit, thereby solving 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 technology, thereby achieving the effect of realizing the wave-by-wave protection function of the multi-channel interleaved parallel topology at a low cost.

[0053] In this embodiment, a current bidirectional wave-by-wave protection method is also provided. Figure 2 is a flow chart of a current bidirectional wave-by-wave protection method according to an embodiment of the present invention. Figure 2 As shown, the process includes the following steps:

[0054] Step S201, sampling each current in a plurality of power supply circuits connected in parallel to obtain a current sampling signal of each current;

[0055] Step S202, dividing the current sampling signals of each channel by diodes to obtain a forward current sampling signal and a negative current sampling signal, summing up all the forward current sampling signals to obtain a maximum forward current value, and summing up all the negative current sampling signals to obtain a minimum negative current value;

[0056] Step S203, comparing the maximum forward current value and the minimum negative current value with the first reference signal value and the second reference signal value respectively in a comparator;

[0057] Step S204, when the maximum value of the forward 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, the comparator outputs a wave-by-wave signal to turn off the PWM drive of the multi-channel interleaved parallel power supply circuit.

[0058] In this embodiment, a current rectification wave-by-wave protection method is also provided. Figure 3 is a flow chart of a current rectification wave-by-wave protection method according to an embodiment of the present invention. Figure 3 As shown, the process includes the following steps:

[0059] Step S301, when each current is an AC signal with a frequency greater than a threshold, sampling each current in a multi-channel staggered parallel power supply circuit to obtain a current sampling signal of each current;

[0060] Step S302, rectifying each current sampling signal into a forward current sampling signal, and summing up the forward current sampling signals of each channel to obtain a maximum current value;

[0061] Step S303, comparing the maximum current value with a third reference signal value in a comparator, and when the maximum current value is greater than the third reference signal value, outputting a wave-by-wave signal through the comparator to turn off the PWM drive of the multi-path staggered parallel power supply circuit.

[0062] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for enabling a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0063] In this embodiment, a current wave-by-wave protection device is also provided, which is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made will not be repeated. As used below, the term "unit" can implement a combination of software and / or hardware of a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0064] Figure 4 is a structural block diagram of a current wave-by-wave protection device according to an embodiment of the present invention. Figure 4 As shown, the device includes a sampling subunit 110 and a wave-by-wave protection subunit 120 .

[0065] The sampling subunit 110 is used to sample the currents of the multiple power supply circuits connected in parallel to obtain sampling signals of the currents of the multiple currents.

[0066] The wave-by-wave protection subunit 120 is used to obtain a directional current sampling signal through a diode from each current sampling signal, and to aggregate the directional current sampling signals to obtain a current extreme value, and to compare the current extreme value with a preset reference signal value through a comparator. When the current extreme value exceeds the reference signal value, the comparator outputs a wave-by-wave signal to shut down the PWM drive of the multi-channel interleaved parallel power supply circuit.

[0067] In an exemplary embodiment, the wave-by-wave protection subunit 120 can also be used to: obtain a forward current sampling signal and a negative current sampling signal respectively by shunting the current sampling signals through diodes, summarize all the forward current sampling signals to obtain a maximum forward current value, and summarize all the negative current sampling signals to obtain a minimum negative current value; compare the maximum forward current value and the minimum negative current value with a first reference signal value and a second reference signal value respectively in a comparator; when the maximum forward current value is greater than the first reference signal value, or the minimum reverse current value is less than the second reference signal value, output a wave-by-wave signal through the comparator to shut down the PWM drive of the multi-channel interleaved parallel power supply circuit.

[0068] In an exemplary embodiment, when each current is an AC signal with a frequency greater than a threshold, the wave-by-wave protection subunit 120 can also be used to: rectify each current sampling signal into a forward current sampling signal, and aggregate the forward current sampling signals to obtain a current maximum value; compare the current maximum value with a third reference signal value in a comparator, and when the current maximum value is greater than the third reference signal value, output a wave-by-wave signal through the comparator to shut down the PWM drive of the multi-channel interleaved parallel power supply circuit.

[0069] In an exemplary embodiment, the sampling subunit 110 may include one of the following: a resistance sampling circuit, a Hall sensor sampling circuit, and a current mutual inductance sampling circuit.

[0070] Figure 5 is a structural block diagram of a current wave-by-wave protection device based on changing the driving duty cycle according to an embodiment of the present invention, such as Figure 5 As shown, the device includes Figure 4 In addition to all the modules shown, a loop algorithm subunit 130 and a PWM drive subunit 140 are also included.

[0071] The loop algorithm subunit 130 is used to calculate the driving duty cycle of each power conversion module in the power conversion module group in the multi-path staggered parallel power supply circuit.

[0072] The PWM driving subunit 140 controls the driving duty cycle of each power conversion module based on the wave-by-wave signal to turn off the PWM driving.

[0073] It should be noted that the above modules can be implemented by software or hardware. For the latter, it can be implemented in the following ways, but not limited to: the above modules are all located in the same processor; or the above modules are located in different processors in any combination.

[0074] An embodiment of the present invention further provides a power conversion device, Figure 6 is a structural block diagram of a power conversion device according to an embodiment of the present invention. Figure 6 As shown, the device includes: a power conversion unit group 200 and a control unit 100.

[0075] 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 a device in any one of the above-mentioned current wave-by-wave protection device embodiments to shut down the PWM drive of the power conversion unit when the power conversion unit 200 is overcurrent.

[0076] In an exemplary embodiment, the electronic device may further include a transmission device and an input-output device, wherein the transmission device is connected to the power conversion device, and the input-output device is connected to the power conversion device.

[0077] For specific examples in this embodiment, reference may be made to the examples described in the above embodiments and exemplary implementation modes, and this embodiment will not be described in detail herein.

[0078] In order to facilitate the understanding of the technical solution provided by the present invention, it will be described in detail below in combination with embodiments of specific scenarios.

[0079] The embodiment of the present invention provides a current wave-by-wave protection circuit that can be used for a multi-channel staggered parallel topology. The circuit does not require additional comparators and TZ* resources of the DSP. It is only necessary to add a few diodes to each current sampling output end, take out the positive sampling signal and negative sampling signal of each current, and respectively converge to obtain the positive maximum value and the negative minimum value. Then the positive maximum value and the negative minimum value are compared with the positive and negative reference values ​​through the comparator to obtain the wave-by-wave signal of the positive and negative current, and are respectively connected to the two TZ* ports of the DSP. When any current is too large, the wave-by-wave protection signal output by the corresponding positive or negative comparator will be flipped to a low level, and the TZ* action will be triggered, and the DSP will immediately turn off all drives to achieve wave-by-wave protection. Therefore, the N-channel staggered parallel topology only needs two comparators and two TZ* ports at most to realize the wave-by-wave protection function of the entire topology circuit. For the wave-by-wave protection of high-frequency resonant current, the maximum value of N-way current can be obtained through full-wave rectification or half-wave rectification circuit, and the wave-by-wave signal is obtained by comparing it with the set reference value through the comparator, and sent to the TZ* port of DSP to close the drive in time to achieve wave-by-wave protection. Therefore, the wave-by-wave protection of N-way high-frequency resonant current only requires one comparator and one TZ* port.

[0080] The purpose of the embodiment of the present invention is to provide a method for current wave-by-wave protection in a multi-way staggered parallel topology to address the problems existing in the prior art. This wave-by-wave protection circuit can achieve comprehensive wave-by-wave protection function in an N-way staggered parallel topology without adding too many additional devices.

[0081] An embodiment of the present invention provides a bidirectional power conversion device, including a power supply unit, a power conversion unit group, a battery unit and a control unit. The power supply unit includes a single-phase DC source, the power conversion unit group includes two power conversion units, and the battery unit includes a plurality of Li batteries connected in series. The positive and negative terminals of the power supply unit are simultaneously connected to each power conversion unit. The output of each power conversion unit is connected in parallel and connected to the positive and negative terminals of the battery unit at the same time. The power supply unit can be used as an input to charge the battery through the power conversion unit group, and the battery unit can also be used as an input to reversely discharge the load through the power conversion unit group.

[0082] The control unit is connected to each power conversion unit, inputs corresponding control signals to each power conversion unit, controls the on-off time of each power conversion unit tube, so that the voltage output by each power conversion unit reaches the target value. The control unit also includes a wave-by-wave protection circuit to ensure that each power conversion unit is quickly shut down in the case of overcurrent.

[0083] The wave-by-wave protection strategy of the embodiment of the present invention adopts the following technical solutions:

[0084] Each current is sampled to obtain a current sampling signal. Each current sampling signal is passed through a diode to obtain a positive current sampling signal and a negative current sampling signal. The positive signals of each current sampling are respectively summarized to obtain the positive maximum value, and the negative current sampling signals are summarized to obtain the negative minimum value. The positive maximum value and the negative minimum value are then compared with their respective reference signals through two comparators. When the maximum value of the positive current is greater than the reference signal, the corresponding comparator output is a low level. When the minimum value of the negative current is less than the corresponding reference signal, the corresponding comparator output is 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. The wave-by-wave signals of the positive and negative currents are sent to the TZ* protection port of the DSP. When the TZ* port receives the wave-by-wave signal at a low level, the DSP immediately turns off the PWM drive, thereby achieving the function of wave-by-wave protection.

[0085] The current sampling of each channel can be performed by resistor sampling, Hall sensor sampling, or current transformer sampling. The comparator can be an external independent comparator or a DSP internal comparator.

[0086] Furthermore, when the current is an AC signal with a relatively high frequency, the current sampling signals of each channel can be rectified into a forward signal, and then the signals of each channel are combined to obtain the maximum value, and this maximum value is compared with a given reference signal to obtain the final wave-by-wave signal. This method doubles the number of diodes required, but only one comparator and TZ* port are used, and the wave-by-wave effect is the same as the above solution.

[0087] The embodiment of the present invention includes a current sampling module, a current sampling signal maximum value selection module and a wave-by-wave signal generation module. The digital controller used in the present invention includes but is not limited to DSP, and other single-chip microcomputers or ARMs can also be implemented. The topology applicable to the present invention is not limited to two-way staggered parallel bidirectional DC-DC converters, and other LLC, PFC, PSFB and other multi-way parallel main power circuits containing transformers and inductors are applicable.

[0088] The embodiment of the present invention provides a simple, easy-to-use, low-cost wave-by-wave protection circuit for a power conversion device with a multi-way staggered parallel topology. The problem that the existing wave-by-wave circuit of the multi-way staggered parallel topology is complex, high cost, and incomplete wave-by-wave function is solved. By adopting this wave-by-wave protection circuit, the wave-by-wave protection function of the N-way staggered parallel topology is fully realized at a very low cost.

[0089] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the optional embodiments of the present invention is clearly and completely described below in conjunction with the drawings in the optional embodiments of the present invention. Based on the optional embodiments of the present invention, all other optional embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the embodiments of the present invention.

[0090] Optional embodiment 1

[0091] A bidirectional DC-DC converter specifically refers to a converter with two or more energy ports. Taking a two-port bidirectional energy converter as an example, one of them is the energy input port and the other is the energy output port. The energy input port and the energy output port can be interchanged, and energy can be transmitted and flowed bidirectionally between the input port and the output port. In order to reduce device current stress and output ripple, multi-path interleaved parallel topology is widely used in bidirectional DC-DC converters.

[0092] Figure 7 is a schematic diagram of the structure of a power conversion device according to an optional embodiment 1 of the present invention, such as Figure 7As shown, the device includes a power supply unit, a power conversion unit group, a battery unit and a control unit. Among them, the power supply unit includes a single-phase DC source, the power conversion unit group includes two power conversion units staggered in parallel, and the battery unit is composed of a plurality of Li batteries connected in series. The positive and negative terminals of the power supply unit are simultaneously connected to each power conversion unit. The output of each power conversion unit is connected in parallel and connected to the positive and negative terminals of the battery unit at the same time. The power supply unit can be used as an input to charge the battery through the power conversion unit group, and the battery unit can also be used as an input to reversely discharge the load connected in parallel to the power supply end through the power conversion unit group.

[0093] Figure 8 is a circuit diagram of a power conversion unit according to an optional embodiment 1 of the present invention, wherein the power conversion unit is as follows Figure 8 As shown, it includes four switching devices Q1, Q2, Q3, Q4, inductor L1, capacitor C in , capacitor C out , the drain of the switch device Q1 is connected to the input voltage POWER+ terminal, the source of Q1 is connected to the first end of the inductor L1 and the drain of Q2 at the same time, the source of Q2 is connected to the input POWER- terminal, the second end of the inductor L1 is connected to the source of Q3 and the drain of Q4 at the same time, the source of Q4 is connected to the output BAT- terminal, the drain of Q3 is connected to the output BAT+, the sources of Q2 and Q4 are connected to the output BAT- terminal at the same time, and the input POWER-- terminal and the output BAT- terminal are the same network. The input and output of the two power conversion units work in parallel, and the switch tube drive works at an interlaced 180o phase, which can reduce the current stress of the tube, reduce losses, and also reduce output ripple.

[0094] Fig. 9 is a control schematic diagram of a power conversion device according to an optional embodiment 1 of the present invention, wherein the control unit is as follows Fig. 9 As shown, the control unit includes a sampling subunit, a loop and algorithm subunit, a wave-by-wave protection subunit, and a PWM drive subunit. In detail, the control unit samples the input voltage, the output voltage, and the inductor current of each power conversion subunit. The drive duty cycle of each power conversion module is calculated by the loop and algorithm subunit. Then, the drive signal of each switch tube is obtained through the PWM drive subunit to control the on and off of the MOS tube in each power conversion subunit, so as to obtain a stable target output voltage. When the inductor current of any one channel is greater than the reference value i0, the wave-by-wave protection circuit outputs a low level, triggers the TZ* module of the DSP, and immediately turns off all drives, thereby realizing the wave-by-wave protection function.

[0095] Fig.10 is a structural block diagram of a wave-by-wave protection circuit according to an optional embodiment 1 of the present invention. Further, as Fig.10The implementation of the wave-by-wave protection function includes the current sampling module M01, the maximum value selection module M02, the wave-by-wave signal generation module M03, and the wave-by-wave function implementation module M04. The implementation of the wave-by-wave protection function can be the TZ* protection function of the main control chip such as DSP, or the protection pin of the PWM driver chip.

[0096] Specifically, the inductor current sampling can be resistor sampling or Hall sensor sampling. In this use case, the Hall sensor is used for sampling. Fig.11 is a circuit diagram of a current sampling module according to an optional embodiment 1 of the present invention, such as Fig.11 As shown, the inductor current flows in from IP+ and flows out from IP-. With VIref as a reference, a current sampling signal corresponding to the magnitude of the inductor current is obtained at the output terminal VIOUT of the Hall chip. If GND is used as a reference, the inductor current sampling signal obtained at the VIOUT port will be superimposed with a +2.5V bias voltage. In order to reduce the sampling error, we perform differential sampling on the current sampling signal between VIOUT and VIref. In the signal conditioning unit, the sampling signal ratio is adjusted through the feedback resistor R8 and the input resistors R2 and R4, and a DC bias voltage is superimposed on the sampling signal through R5 and R6, so that both the positive current and the negative current can be sampled without distortion. Among them, R8=R6, R7=R5, R1=R2, and R3=R4. Resistor R9 and capacitor C1 form an RC filter unit to filter out high-frequency interference in the current sampling signal. The relationship between the sampling signal and the inductor current is:

[0097]

[0098] Where IL1 is the inductor current, and K is the sampling accuracy of the Hall chip. The obtained current sampling signal IL1_Sample is directly sent to the DSP for loop operation. At the same time, IL1_Sample and IL2_Sample are also sent to the wave-by-wave protection circuit to generate wave-by-wave signals.

[0099] In detail, in a bidirectional DC-DC converter, since energy can flow in both directions, the inductor current is also bidirectional. When the power module charges the battery, the current flows from left to right, and the current direction is positive. When the battery discharges the load, the current flows from right to left, and the direction is negative. Fig.12 is a circuit diagram of a wave-by-wave protection circuit according to an optional embodiment 1 of the present invention, such as Fig.12 As shown, the wave-by-wave protection circuit includes a maximum value selection module and a wave-by-wave signal generation module. The value must be equal to the DC bias voltage in the inductor current sampling circuit. When the battery is charging, the inductor current sampling signal IL1_Sample passes through R1, VD2, and R4 and merges with another inductor current signal IL2_Sample passing through R2, VD4, and R6 to obtain the maximum value of the two. The forward maximum value passes through the voltage follower and the RC filter circuit to obtain IL_P_COMP, which is sent to the wave-by-wave signal generation module. The wave-by-wave signal generation module is composed of a comparator, which can be built by external discrete components or a DSP internal integrated comparator. The reference voltage Vref_P is set at the non-inverting input of the comparator. Under normal circumstances, the maximum forward inductor current IL_P_COMP is less than the reference voltage Vref_P, and the comparator output TZ*_P is high. Fig.13 is a wave-by-wave protection waveform diagram of a battery during charging according to an optional embodiment 1 of the present invention, such as Fig.13 As shown in the figure, when the inductor current is too large under abnormal conditions, IL_P_COMP is greater than Vref_P, and the comparator output TZ*_P flips to a low level. TZ*_P is the wave-by-wave protection signal of the forward inductor current when the battery is charged, and this signal is connected to the TZ* port of the DSP. When TZ*_P is low, the DSP immediately turns off all drivers, and when TZ*_P returns to a high level, the drivers also resume, thereby achieving wave-by-wave protection.

[0100] Fig.14 is a wave-by-wave protection waveform diagram of a battery during discharge according to an optional embodiment 1 of the present invention, such as Fig.14 As shown in the figure, the wave-by-wave protection function of the battery during discharge is similar to that during charging. The inductor current flows from right to left. IL1_Sample and IL2_Sample are respectively combined through R1, VD1, R3 and R2, VD3, R5 to obtain the negative minimum value, and then IL_N_COMP is obtained through the voltage follower and RC filter circuit, and sent to the same-direction input of the comparator. The reference voltage Vref_N is given at the reverse input of the comparator. Under normal circumstances, IL_N_COMP is greater than Vref_N, and the comparator output TZ*_N is high. Under abnormal circumstances, when the inductor current is too large, IL_N_COMP is less than Vref_N, and the comparator output TZ*_N is low, triggering the DSP to turn off all drivers to achieve the wave-by-wave protection function.

[0101] Through the above method, only two diodes need to be added to each wave-by-wave circuit to separate the positive inductor current sampling signal and the negative inductor current sampling signal. All positive current signals take the maximum value, and the negative current signals take the minimum value, and the positive wave-by-wave signal and the negative wave-by-wave signal are obtained through the comparator respectively. Then they are sent to the TZ* port of the DSP respectively. When any wave-by-wave signal is negative, all drivers are immediately turned off, thereby realizing the wave-by-wave protection function of each inductor current. The entire wave-by-wave protection circuit only needs two comparators, two TZ* ports and 2N diodes to realize the wave-by-wave protection of N-way staggered parallel topology.

[0102] The controller in the above technical solution includes but is not limited to single-chip microcomputer, DSP, ARM, etc. The wave-by-wave mode is not limited to immediately resuming the drive after the wave-by-wave signal disappears, and can also be set to resume the drive after the wave-by-wave low-level signal disappears for one or more switching cycles as needed. The implementation of wave-by-wave protection is not limited to shutting down the drive by the TZ* function of the DSP, and other methods such as directly controlling each driver chip through the wave-by-wave signal can also be used to shut down and restore the PWM drive. This technical solution can be used for but not limited to two-way interlaced parallel bidirectional DC-DC devices, and can also be used for wave-by-wave protection of any multi-way interlaced topology.

[0103] Optional Embodiment 2

[0104] The power part of this embodiment is a three-phase high-power combined topology. Fig.15 is a control schematic diagram of a power conversion device according to an optional second embodiment of the present invention, such as Fig.15 As shown, the device mainly includes a power supply unit, an inductance unit, a power conversion unit group, a BUS capacitor and a control unit. Among them, the power supply unit includes a three-phase AC source, the three inductance units are composed of inductances to realize the charging and discharging of the power circuit, and the power conversion unit group includes three power conversion units. The three-phase output of the power supply unit is respectively connected in series with the three inductance units, one end input of each power conversion unit is connected to the corresponding inductance unit, and the other end is star-connected together. The output of each power conversion unit is connected to a BUS capacitor. The output BUS voltage of each power conversion unit is used as the power conversion result of the power conversion device.

[0105] Fig.16 is a circuit diagram of a power conversion unit according to an optional second embodiment of the present invention, wherein the power conversion unit is as follows Fig.16As shown, Q1 and Q2 are two power MOS tubes, which are high-frequency switching tubes. The driving PWM1 and PWM2 are calculated by the control unit. The on-off time of the MOS tube is controlled by controlling the size of the PWM driving duty cycle, thereby controlling the size of the BUS capacitor C1 voltage. VT1 and VT2 are power frequency return tubes, including but not limited to power diodes, and power switching tubes such as MOS tubes can also be used. The midpoint COM of the high-frequency MOS tube is connected to the boost inductor, and the midpoint N of the power frequency diode is connected to the N point of other power units to form a star connection.

[0106] The control unit samples the input line voltage, three inductor currents and the BUS voltage, and obtains the control signal of each power conversion module through loop control calculation, thereby obtaining a stable BUS voltage. In detail, the control unit includes a sampling subunit, a loop algorithm subunit, a wave-by-wave protection subunit and a PWM drive subunit.

[0107] Specifically, the sampling subunit samples the line voltage of the three-phase power supply, the inductor current of the three-phase inductor, and the BUS voltage of the three-phase BUS through signal conditioning circuits such as operational amplifiers, and sends the sampled analog quantity to the ADC port of the main control chip DSP. Furthermore, the analog-to-digital conversion subunit inside the DSP converts the sampled analog signal into a digital signal, restores the actual voltage and current values, and participates in the calculation of the loop and algorithm subunits. The PWM drive signal of each phase power switch is obtained, thereby controlling the opening and closing of the power switch to achieve accurate output of the BUS voltage. When the circuit is abnormal and the three-phase inductor current is too high, the wave-by-wave protection subunit generates a low-level wave-by-wave signal, which quickly triggers the DSP to shut down the PWM drive, and restores the drive when the wave-by-wave signal disappears, thereby realizing the wave-by-wave protection function of the three-phase high-power PFC.

[0108] The inductor current in the three-phase combined conversion topology is a 50HZ industrial frequency AC signal, and its signal sampling circuit is the same as that in the first embodiment, and both use a Hall chip for sampling. Further, Fig.17 : is a circuit diagram of a wave-by-wave protection circuit according to an optional embodiment 2 of the present invention. The wave-by-wave protection circuit in the device is as follows: Fig.17 shown. Fig.18 is a waveform diagram of the wave-by-wave protection according to the optional embodiment 2 of the present invention. The circuit waveform corresponding to the wave-by-wave protection circuit in the device is as follows: Fig.18 As shown. The three-phase inductor current signals Ia_Sample, Ib_Sample and Ic_Sample are used to obtain the maximum current signals of the positive and negative half cycles through the maximum value selection module. Then IL_P_COMP and IL_N_COMP are obtained through the voltage follower and RC filter circuit, as shown Fig.12The maximum current signal of the positive and negative half cycles enters the wave-by-wave signal generation module, and is compared with the set reference voltages Vref_P and Vref_N to obtain the positive half-cycle wave-by-wave signal TZ*_P and the negative half-cycle wave-by-wave signal TZ*_N.

[0109] Specifically, Fig.19 : is a waveform diagram of the wave-by-wave protection function according to the optional embodiment 2 of the present invention, such as Fig.19 As shown, under normal working conditions, the maximum inductor current sampling signal IL_P_COMP of the positive half cycle is less than the reference signal Vref_P, and the corresponding positive half cycle wave-by-wave signal TZ*_P is high. When the positive half cycle inductor current of any phase is too large, IL_P_COMP will be greater than the reference signal Vref_P, causing the positive half cycle wave-by-wave signal TZ*_P output by the comparator to flip to a low level. Similarly, under normal working conditions, 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 high. When the negative half cycle inductor current of any phase is too large, IL_N_COMP will be less than the reference signal Vref_N, causing the negative half cycle wave-by-wave signal TZ*_N output by the comparator to flip to a low level. When either the positive half-cycle ripple signal TZ*_P or the negative half-cycle ripple signal TZ*_N is at a low level, the TZ* module of the DSP will be triggered to immediately shut down all drivers, and the driving will be restored after all the ripple signals are flipped to a high level. You can also set the driving to be restored after all the ripple signals disappear for one or more switching cycles as needed.

[0110] The above method still only requires two comparators and two TZ* ports to realize the wave-by-wave protection function of the three-phase PFC power frequency inductor current. The circuit is simple, the cost is low, and the wave-by-wave protection is comprehensive and timely. The controller in the above technical solution includes but is not limited to a single-chip microcomputer, a DSP, an ARM, etc. The wave-by-wave protection method is not limited to shutting down the drive by the TZ* function of the DSP, and other methods such as directly controlling each driver chip through the wave-by-wave signal can also be used to realize the shutdown and recovery of the PWM drive.

[0111] Optional embodiment three

[0112] This embodiment is directed to a topology in which the inductor current is a high-frequency resonant current. Taking an LLC topology in which two paths are staggered 180° in parallel as an example, the frequency of the resonant inductor current is the same as the switching frequency. Fig. 20 is a circuit diagram of an inductor current sampling circuit according to an optional third embodiment of the present invention, such as Fig. 20 As shown in FIG. 1 , an auxiliary winding is added to the resonant inductor to obtain an inductor current sampling signal. By changing the turns ratio of the inductor and the auxiliary winding, the amplitude of the current sampling signal can be changed.

[0113] Furthermore, Fig.21is a circuit diagram of a full-wave rectification wave-by-wave protection circuit according to an optional third embodiment of the present invention, Fig. 22 : is a waveform diagram of a full-wave rectifier wave-by-wave protection circuit according to an optional embodiment 3 of the present invention, such as Fig.21 , 22 As shown, each inductor current sampling signal is full-wave rectified through a rectifier bridge composed of four diodes. IL1_Sample+ and IL1_Sample- charge capacitor C1 through a rectifier bridge composed of VD1~VD4, and rectify the negative signal of the current sampling signal of inductor L1 to the positive direction. The current sampling signal of inductor IL2 is processed in the same way. Finally, the two rectified signals are connected together to obtain the maximum current signal after rectification of the two inductor currents. The maximum value IL_COMP of each inductor current sampling signal is obtained through the RC filter circuit composed of R5 and C3 and the clamping diode composed of VD9 and VD10. IL_COMP is sent to the inverting input of the comparator, and the reference signal Vref is given at the non-inverting input of the comparator. 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 inductor current is too high, the maximum value of the inductor current sampling signal IL_COMP is greater than the reference value Vref, and the comparator output TZ*_sum flips to a low level, triggering the DSP to immediately shut down the drive to prevent the device from being damaged by overcurrent, thereby realizing the wave-by-wave protection function. The wave-by-wave protection is set to shut down the drive for 3 switching cycles in the figure, and the wave-by-wave protection time can also be set as needed.

[0114] For the topology where the inductor current is a high-frequency resonant current, this embodiment further proposes another wave-by-wave protection circuit. Fig.23 is a circuit diagram of a half-wave rectifier wave-by-wave protection circuit according to an optional third embodiment of the present invention, Fig.24 : is a waveform diagram of a half-wave rectifier wave-by-wave protection circuit according to an optional third embodiment of the present invention, such as Fig.23 , 24As shown, the circuit is a half-wave rectifier circuit. 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 VD1. The sampling signal of the positive half cycle of the other channel is obtained in the same way. The positive half cycle of the two signals takes the maximum value, and the maximum signal IL_COMP of the positive half cycle of the two inductor currents is obtained through the RC filter circuit composed of R7 and C3 and the clamping circuit composed of VD3 and VD4. Similarly, the signal is sent to the reverse input of the comparator, and the reference signal Vref is given at the in-phase input of the comparator. 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 inductor current is too high, the maximum value of the inductor current sampling signal IL_COMP is greater than the reference value Vref, and the comparator output TZ*_sum flips to a low level, triggering the DSP to immediately shut down the drive to prevent the device from being damaged by overcurrent, thereby realizing the wave-by-wave protection function. The wave-by-wave protection in the figure is set to shut down the drive for 3 switching cycles, and the wave-by-wave protection time can also be set as needed.

[0115] In the above embodiment, only one comparator and one TZ* port are needed to realize the wave-by-wave protection function of multiple high-frequency resonant inductor currents, thereby simplifying the complexity of the existing wave-by-wave protection circuit structure and reducing the circuit cost.

[0116] It should be noted that the controller in the above technical solution includes but is not limited to single-chip microcomputer, DSP, ARM, etc. The wave-by-wave protection method is not limited to shutting down the drive by the TZ* function of the DSP, and other methods such as directly controlling each driver chip through the wave-by-wave signal can also be used to achieve the shutdown and recovery of the PWM drive. This solution is not limited to the LLC resonant topology, and is applicable to any single-channel or multi-channel staggered parallel topology with high-frequency AC current.

[0117] Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A current wave-by-wave protection method, characterized in that: include: Sampling each current in a multi-channel power supply circuit connected in parallel to obtain each current sampling signal; Passing each current sampling signal through a diode to obtain a directional current sampling signal, and summing up the directional current sampling signals to obtain a current extreme value; The current extreme value is compared with a preset reference signal value by a comparator, and when the current extreme value exceeds the reference signal value, a wave-by-wave signal is output by the comparator to turn off the PWM drive of the multi-path staggered parallel power supply circuit; The current sampling signals of each channel are passed through a diode to obtain a directional current sampling signal, and the directional current sampling signals are aggregated to obtain a current extreme value, including: The current sampling signals of each channel are shunted by diodes to obtain a forward current sampling signal and a negative current sampling signal, all the forward current sampling signals are aggregated to obtain a maximum forward current value, and all the negative current sampling signals are aggregated to obtain a minimum negative current value; or, When each current is an AC signal with a frequency greater than a threshold, each current sampling signal is passed through a diode to obtain a directional current sampling signal, and the directional current sampling signals are aggregated to obtain a current extreme value, including: The current sampling signals of each channel are rectified into forward current sampling signals respectively, and the forward current sampling signals of each channel are aggregated to obtain the maximum current value.

2. The method according to claim 1, characterized in that The current extreme value is compared with a preset reference signal value by a comparator, and when the current extreme value exceeds the reference signal value, a wave-by-wave signal is output by the comparator to turn off the PWM drive of the multi-path staggered parallel power supply circuit, including: In a comparator, the maximum forward current value and the minimum negative current value are compared with a first reference signal value and a second reference signal value respectively; When the maximum value of the forward 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, the comparator outputs a wave-by-wave signal to turn off the PWM drive of the multi-channel interleaved parallel power supply circuit.

3. The method according to claim 1, characterized in that The current extreme value is compared with a preset reference signal value by a comparator, and when the current extreme value exceeds the reference signal value, a wave-by-wave signal is output by the comparator to turn off the PWM drive of the multi-path staggered parallel power supply circuit, including: The current maximum value is compared with a third reference signal value in a comparator. When the current maximum value is greater than the third reference signal value, a wave-by-wave signal is output through the comparator to turn off the PWM drive of the multi-path interleaved parallel power supply circuit.

4. The method according to claim 1, characterized in that: The PWM drive of the multi-path interleaved parallel power supply circuit is shut down by outputting a wave-by-wave signal through the comparator, comprising: Outputting a wave-by-wave signal to a TZ* protection port of a DSP through the comparator; When the TZ* protection port determines that the received wave-by-wave signal is at a low level, the DSP turns off the PWM drive of the multi-channel staggered parallel power supply circuit.

5. A wave-by-wave protection circuit, characterized in that: include: A current sampling circuit, a maximum value selection circuit and a wave-by-wave signal generating circuit are connected in sequence, wherein The current sampling circuit samples the currents of the multiple power supply circuits connected in parallel and outputs the current sampling signals of the multiple currents respectively. A maximum value selection circuit, the input end of which is connected to the output end of the current sampling subcircuit, rectifies or filters the current sampling signals of each channel into a directional current sampling signal, aggregates the directional current sampling signals to obtain a current extreme value, and outputs the current extreme value; a wave-by-wave signal generating circuit, wherein a first input terminal of the circuit is connected to an output terminal of the maximum value selecting circuit to input the current extreme value, and a second input terminal of the circuit is used to input a preset reference signal value, and when the current extreme value exceeds the reference signal value, the circuit outputs a wave-by-wave signal to turn off the PWM drive of the multi-channel interleaved parallel switch power supply circuit; Wherein, the maximum value selection circuit has multiple input terminals, each input terminal corresponds to a current sampling signal, and each input terminal is connected to two diodes in parallel to filter each input sampling signal into a positive current sampling signal and a negative current sampling signal. The positive current sampling signals of each sampling signal are aggregated and superimposed with a first bias voltage, and connected to a first follower. The first follower outputs the maximum value of the positive current. The negative current sampling signals of each sampling signal are aggregated and superimposed with a second bias voltage, and connected to a second follower. The second follower outputs the maximum value of the negative current. or, The maximum value selection circuit includes a plurality of diode rectifier bridges connected in parallel, a bias voltage and a follower connected in sequence, wherein the plurality of diode rectifier bridges connected in parallel rectify each current sampling signal into a forward current sampling signal, and superimpose the bias voltage before inputting the signal into the follower, and the output end of the follower outputs the maximum forward current value in the forward current sampling signal.

6. The wave-by-wave protection circuit according to claim 5, characterized in that: The wave-by-wave signal generating circuit comprises a first comparator and a second comparator, wherein: The inverting input terminal of the first comparator is used to input the maximum forward current value output by the maximum value selection circuit, and the non-inverting input terminal of the first comparator is used to input a preset first reference signal value. When the maximum forward current value is greater than the first reference signal value, the first comparator flips and outputs a wave-by-wave signal at the output terminal; The inverting input terminal of the second comparator is used to input the maximum negative current output by the maximum value selection circuit, and the non-inverting input terminal of the second comparator is used to input a preset second reference signal value. When the minimum negative current is less than the second reference signal value, the second comparator flips to output a wave-by-wave signal at the output terminal.

7. The wave-by-wave protection circuit according to claim 5, characterized in that: The wave-by-wave signal generating circuit includes a comparator, wherein the inverting input terminal of the comparator is used to input the maximum forward current value output by the maximum value selection circuit, and the non-inverting input terminal of the comparator is used to input a preset third reference signal value. When the maximum current value is greater than the third reference signal value, the comparator flips to output a wave-by-wave signal at the output terminal.

8. The wave-by-wave protection circuit according to claim 5, characterized in that: The sampling circuit is one of the following: a resistance sampling circuit, a Hall sensor sampling circuit, and a current mutual inductance sampling circuit.

9. The wave-by-wave protection circuit according to claim 5, characterized in that: Also includes: The PWM driving circuit has an input end connected to the output end of the wave-by-wave signal generating circuit, and generates a PWM driving signal based on the input low-level wave-by-wave signal.

10. A power conversion device, characterized in that: include: A power conversion unit group and a control unit, wherein the control unit is respectively connected to each power conversion unit in the power conversion unit group, and the control unit includes a wave-by-wave protection circuit according to any one of claims 5 to 9, so as to control the driving duty cycle of each power conversion module by outputting a PWM driving signal to shut down the PWM drive of the power conversion unit when the power conversion unit is overcurrent.

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