Power conversion device and control method for power converter

Abstract

The application provides a power conversion device and a control method of a power converter, which comprises: a power factor correction circuit, comprising at least one switch tube, an input end and an output end, the input end is used for receiving an industrial frequency alternating current input signal, the output end is connected with a direct current bus, and the power factor correction circuit is used for realizing power factor correction; a main power conversion module, comprising at least one switch tube, an input end and an output end, the input end is connected with the direct current bus, and the output end is used for being connected with a load, and the main power conversion module is used for performing power conversion on an electric signal on the direct current bus to supply power for the load; and a digital control unit, which receives a first detection signal from the main power conversion module and outputs a switch control signal for controlling the power factor correction circuit according to the first detection signal, wherein the first detection signal represents a state of the load.

Description

Technical Field

[0001] This application relates to the field of power supply, and in particular to power conversion devices and control methods for power converters. Background Technology

[0002] In the power supply field, power converters are commonly used to convert industrial frequency AC power into another AC power to power AC loads, or to convert industrial frequency AC power into DC power to power DC loads.

[0003] For details, please refer to Figure 1 The diagram shows a typical power converter. The power converter includes a power factor correction circuit 100, comprising at least one switch, an input terminal, and an output terminal. The input terminal receives a power frequency AC input signal Vacin, and the output terminal is connected to a DC bus 200. The power factor correction circuit 100 is used to perform power factor correction. A main power conversion module 300 includes at least one switch, an input terminal, and an output terminal. The input terminal is connected to the DC bus 200, and the output terminal is used to connect to a load. The main power conversion module 300 is used to convert the electrical signal on the DC bus 200 to supply power to the load.

[0004] In practical applications, with the introduction of the new PCIe 5.1 standard and EDPP POWER LOADING by Intel, the dynamic load on power converters is increasing. For example, in GPU (Graphics Processing Unit) applications, the load dynamics change significantly, requiring the power factor correction circuit's control loop to adjust rapidly. However, in current traditional applications, the control loop of the power factor correction circuit 100 adjusts the loop by detecting the DC bus 200 voltage. Because the voltage change of the large capacitor is relatively slow, and the power factor correction circuit needs to perform power correction tasks, the loop's dynamic response is also relatively slow. This results in large fluctuations in the DC bus 200 voltage, easy distortion of the input current, and problems such as large adjustment delays and overshoot. While increasing the gain of the main power conversion module 300, increasing the capacitance of the DC bus 200 capacitor, or enhancing the power devices in the power factor correction circuit can meet input and output requirements, this leads to a larger power converter size and higher cost.

[0005] Therefore, it is evident that existing technologies cannot solve the input current distortion and power factor abnormalities caused by high-output dynamic load adjustment. Summary of the Invention

[0006] According to one embodiment, a power conversion device is provided, comprising: a power factor correction circuit, including at least one switching transistor, an input terminal, and an output terminal, wherein the input terminal is used to receive an AC input signal at power frequency, and the output terminal is connected to a DC bus, and the power factor correction circuit is used to perform power factor correction; a main power conversion module, including at least one switching transistor, an input terminal, and an output terminal, wherein the input terminal is connected to the DC bus, and the output terminal is used to connect to a load, and the main power conversion module is used to perform power conversion on the electrical signal on the DC bus to supply power to the load; and a digital control unit, receiving a first detection signal from the main power conversion module, and outputting a switching control signal for controlling the power factor correction circuit according to the first detection signal, wherein the first detection signal characterizes the state of the load.

[0007] Furthermore, the digital control unit performs the following actions: obtaining a loop compensation value based on the first detection signal; and outputting a switching control signal to control the power factor correction circuit based on the loop compensation value and a second detection signal from the power factor correction circuit.

[0008] Furthermore, the digital control unit performs the following: when the first detection signal exceeds a threshold range, the loop compensation value is obtained based on the slope of the change of the first detection signal and a compensation coefficient k; when the first detection signal is within the threshold range, the loop compensation value is 0.

[0009] Furthermore, the digital control unit also receives a load prediction change signal from the load, and obtains the loop compensation value based on the first detection signal and the load prediction change signal.

[0010] Furthermore, the digital control unit performs the following: when the first detection signal exceeds a threshold range, the loop compensation value is obtained by combining the slope of the change of the first detection signal and the compensation coefficient k with the load prediction change signal in a certain weight ratio.

[0011] Furthermore, the loop compensation value is superimposed on the output of the voltage loop of the power factor correction circuit, or superimposed on the reference voltage signal of the voltage loop of the power factor correction circuit.

[0012] Furthermore, the digital control unit includes: a first arithmetic unit for obtaining the loop compensation value based on the first detection signal; a second arithmetic unit for obtaining a first voltage difference signal based on the DC bus voltage signal from the DC bus and a reference voltage signal; a third arithmetic unit for superimposing the loop compensation value onto the first voltage difference signal to obtain a second voltage difference signal; a fourth arithmetic unit for obtaining a current reference signal based on the second voltage difference signal and a voltage detection signal from the power factor correction circuit; and a control signal generation unit for outputting a switching control signal for controlling the power factor correction circuit based on the current reference signal and the current detection signal from the power factor correction circuit.

[0013] Furthermore, the digital control unit includes: a first arithmetic unit for obtaining the loop compensation value based on the first detection signal; a third arithmetic unit for superimposing the loop compensation value onto a reference voltage signal to obtain a second reference voltage signal; a second arithmetic unit for obtaining a voltage difference signal based on the DC bus voltage signal from the DC bus and the second reference voltage signal; a fourth arithmetic unit for obtaining a current reference signal based on the voltage difference signal and a voltage detection signal from the power factor correction circuit; and a control signal generation unit for outputting a switching control signal for controlling the power factor correction circuit based on the current reference signal and the current detection signal from the power factor correction circuit.

[0014] This application also provides a control method for a power converter, wherein the power converter includes a power factor correction circuit, including at least one switch, an input terminal, and an output terminal. The input terminal is used to receive a power frequency AC input signal, and the output terminal is connected to a DC bus. The power factor correction circuit is used to implement power factor correction. A main power conversion module includes at least one switch, an input terminal, and an output terminal. The input terminal is connected to the DC bus, and the output terminal is used to connect to a load. The main power conversion module is used to perform power conversion on the electrical signal on the DC bus to supply power to the load, including: S1: detecting a first detection signal from the main power conversion module; S2: determining whether the first detection signal is within a threshold range, and if so, proceeding accordingly. Proceed to step S3; if not, proceed to step S4. S3: Output loop compensation value is 0; proceed to step S5. S4: Obtain the loop compensation value based on the slope of the first detection signal and a compensation coefficient k. S5: Superimpose the loop compensation value onto the output of the voltage loop of the power factor correction circuit, or onto the reference voltage signal of the voltage loop of the power factor correction circuit; the voltage loop of the power factor correction circuit outputs a voltage difference signal. S6: Obtain a current reference signal based on the voltage difference signal and the voltage detection signal from the power factor correction circuit. S7: Output a switching control signal to control the power factor correction circuit based on the current reference signal and the current detection signal from the power factor correction circuit.

[0015] Furthermore, in step S5: when the power factor correction circuit's AC input voltage signal crosses zero, the loop compensation value is superimposed on the output of the power factor correction circuit's voltage loop, or superimposed on the reference voltage signal of the power factor correction circuit's voltage loop.

[0016] Furthermore, in step S1, a load prediction change signal from the load is also received; in step S4, the loop compensation value is obtained by matching the change slope of the first detection signal and the compensation coefficient k with the load prediction change signal in a certain weight ratio.

[0017] The features and technical advantages of this disclosure have been outlined quite extensively above to facilitate a better understanding of the detailed description that follows. Additional features and advantages of this disclosure, which form the subject matter of the claims, will be described below. Those skilled in the art will understand that the disclosed concepts and specific embodiments can be readily used as the basis for modifying or designing other structures or processes for achieving the same purpose as this disclosure. Those skilled in the art will also recognize that such equivalent structures do not depart from the spirit and scope of this disclosure as set forth in the appended claims. Attached Figure Description

[0018] To gain a more complete understanding of this disclosure and its advantages, the following description is given in conjunction with the accompanying drawings, wherein: Figure 1 A schematic diagram of a typical power converter is shown; Figure 2 A schematic diagram of a power conversion device according to an embodiment of this application is shown; Figure 3 A schematic diagram of a power conversion device according to another embodiment of this application is shown; Figure 4 A schematic diagram of a power conversion device according to another embodiment of this application is shown; Figure 5 A schematic diagram of a power conversion device according to another embodiment of this application is shown; Figure 6 A schematic diagram of a power conversion device according to another embodiment of this application is shown; Figure 7 A schematic diagram of a power conversion device according to another embodiment of this application is shown; Figure 8 A flowchart of a control method for a power converter according to another embodiment of this application is shown.

[0019] Unless otherwise stated, corresponding numbers and symbols in the various figures generally refer to corresponding parts. These figures are drawn to clearly illustrate relevant aspects of the various embodiments and are not necessarily drawn to scale. Detailed Implementation

[0020] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] One embodiment of this application provides a power conversion device. For details, please refer to [link to relevant documentation]. Figure 2 The diagram shown illustrates a power conversion device according to an embodiment of this application. The power conversion device proposed in this application includes: The power factor correction circuit 100 includes at least one switching transistor, an input terminal, and an output terminal. The input terminal is used to receive the power frequency AC input signal Vacin, and the output terminal is connected to the DC bus 200. The power factor correction circuit 100 is used to implement power factor correction. The main power conversion module 300 includes at least one switching transistor, an input terminal, and an output terminal. The input terminal is connected to the DC bus 200, and the output terminal is used to connect to a load. The main power conversion module 300 is used to convert the electrical signal on the DC bus 200 to supply power to the load. The digital control unit 400 receives a first detection signal Sc from the main power conversion module 300 and outputs a switching control signal Cr to control the power factor correction circuit 100 according to the first detection signal Sc, wherein the first detection signal Sc represents the state of the load.

[0022] Thus, the power factor correction circuit 100 obtains a switching control signal Cr to control itself based on the first detection signal Sc, which characterizes the state of the load, from the main power conversion module 300. The main power conversion module 300 has a relatively fast response speed, on the order of microseconds (e.g., hundreds of microseconds). Dynamic changes in the load can be quickly responded to by the first detection signal Sc from the main power conversion module 300, such as the switching frequency or duty cycle. The power factor correction circuit 100 obtains the switching control signal Cr based on the first detection signal Sc, which characterizes the state of the load, effectively monitoring the load in real time. This allows it to quickly respond to load changes before significant changes in the DC bus 200 voltage, improving the stability of the power converter under high-output dynamic load conditions.

[0023] Furthermore, the digital control unit 400 performs the following actions: obtaining a loop compensation value based on the first detection signal Sc; and outputting a switching control signal Cr to control the power factor correction circuit 100 based on the loop compensation value and a second detection signal from the power factor correction circuit 100. That is, the control loop of the power factor correction circuit 100 is compensated based on the first detection signal Sc, which characterizes the load state, from the main power conversion module 300. This ensures that the control loop of the power factor correction circuit 100 no longer relies solely on the relatively slow dynamic response of the DC bus 200 voltage, allowing the control loop of the power factor correction circuit 100 to respond quickly to load changes.

[0024] Furthermore, the aforementioned control is implemented by programming the digital control unit 400, which has a low dependence on hardware. With less wiring and cost, it can improve the input-output problems caused by large dynamic output in practical applications, and has wide applicability and high operability.

[0025] Furthermore, the digital control unit 400 performs the following: when the first detection signal Sc exceeds a threshold range, the loop compensation value is obtained based on the slope of the change of the first detection signal Sc and a compensation coefficient k; when the first detection signal Sc is within the threshold range, the loop compensation value is 0.

[0026] Taking the first detection signal Sc as the switching frequency of the switching transistor in the main power conversion module 300 as an example, when the load experiences large dynamic changes, the switching frequency of the switching transistor in the main power conversion module 300 will change within microseconds, such as increasing or decreasing. When the first detection signal Sc exceeds a frequency threshold range, it indicates that the large dynamic changes of the load exceed the normal modulation range of the power converter. At this time, the loop compensation value is obtained based on the slope of the change of the first detection signal Sc and a compensation coefficient k to compensate the voltage loop of the power factor correction circuit 100, thereby affecting the control signal controlling the power factor correction circuit 100, so that the power factor correction circuit 100 can quickly respond to the large dynamic changes of the load. The aforementioned frequency threshold range refers to the frequency variation range of the switching transistors within the main power conversion module 300 when the load varies within the normal range, with a certain margin. For example, the frequency variation range of the switching transistors within the main power conversion module 300 is between 60kHz and 70kHz when the load varies within the normal range. With a certain margin, the frequency threshold range can be set between 50kHz and 80kHz. Of course, this can be determined according to the actual application environment of the power converter.

[0027] In practical applications, the slope of the change in the first detection signal Sc (such as the slope of the frequency change) represents the load change. Therefore, the loop compensation value is obtained by multiplying the slope of the change in the first detection signal Sc by the compensation coefficient k. In practical applications, the compensation coefficient k can be determined according to the actual product.

[0028] In practical applications, this application does not limit the first detection signal Sc to the frequency of the switching transistor in the main power conversion module 300. It can also be the duty cycle of the switching transistor in the main power conversion module 300, the input current of the main power conversion module 300, the output current of the main power conversion module 300, or the output voltage of the main power conversion module 300. Any signal that can characterize the state of the load is applicable to this application.

[0029] In practical applications, in one embodiment of this application, the loop compensation value is superimposed on the output of the voltage loop of the power factor correction circuit, or superimposed on the reference voltage signal Vref of the voltage loop of the power factor correction circuit.

[0030] For details, please refer to Figure 3 The diagram shown is a power conversion device schematic of another embodiment of this application, and can be combined with... Figure 2The digital control unit 400 includes: a first arithmetic unit 410, which obtains the loop compensation value M based on the first detection signal Sc; a second arithmetic unit 420, which obtains a first voltage difference signal Veao1 based on the DC bus voltage signal Vbus from the DC bus 200 and the reference voltage signal Vref; a third arithmetic unit 430, which superimposes the loop compensation value M onto the first voltage difference signal Veao1 to obtain a second voltage difference signal Veao2; a fourth arithmetic unit 440, which obtains a current reference signal Iref based on the second voltage difference signal Veao2 and the voltage detection signal Vs from the power factor correction circuit 100; and a control signal generation unit 450, which outputs a switching control signal Cr to control the power factor correction circuit 100 based on the current reference signal Iref and the current detection signal Is from the power factor correction circuit 100.

[0031] It can be seen that the control loop of the power factor correction circuit 100 includes an outer voltage loop and an inner current loop, such as... Figure 3 As shown, the second arithmetic unit 420 and the third arithmetic unit 430 constitute the voltage outer loop, and the fourth arithmetic unit 440 and the control signal generation unit 450 constitute the current inner loop. In this embodiment, the loop compensation value M obtained based on the first detection signal Sc is superimposed on the output Veao of the voltage outer loop, thereby affecting the current reference signal Iref of the current inner loop, and thus affecting the switching control signal Cr that controls the power factor correction circuit 100.

[0032] For details, please refer to Figure 4 The diagram shown is a power conversion device schematic of another embodiment of this application, and can be combined with... Figure 2 The digital control unit 400 includes: a first arithmetic unit 410, which obtains the loop compensation value M based on the first detection signal Sc; a third arithmetic unit 430, which superimposes the loop compensation value M onto the reference voltage signal Vref to obtain a second reference voltage signal Vref2; a second arithmetic unit 420, which obtains a voltage difference signal Veao based on the DC bus voltage signal Vbus from the DC bus 200 and the second reference voltage signal Vref2; a fourth arithmetic unit 440, which obtains a current reference signal Iref based on the voltage difference signal Veao and the voltage detection signal Vs from the power factor correction circuit 100; and a control signal generation unit 450, which outputs a switching control signal Cr to control the power factor correction circuit 100 based on the current reference signal Iref and the current detection signal Is from the power factor correction circuit 100.

[0033] In this embodiment, the loop compensation value M obtained based on the first detection signal Sc is superimposed on the reference voltage signal Vref, thereby affecting the current reference signal Iref of the inner current loop, and thus affecting the switching control signal Cr that controls the power factor correction circuit 100.

[0034] In actual implementation, the second operation unit 420 and the fourth operation unit 440 can be implemented as error amplifiers, and the third operation unit 430 can be implemented as an adder.

[0035] In another embodiment of this application, the digital control unit 400 further receives a load prediction change signal Ls from the load, and obtains the loop compensation value M based on the first detection signal Sc and the load prediction change signal Ls.

[0036] For details, please refer to Figure 5 The schematic diagram of a power conversion device according to another embodiment of this application shows that the first arithmetic unit 410 within the digital control unit 400 further receives a load prediction change signal Ls from the load, and obtains the loop compensation value M based on the first detection signal Sc and the load prediction change signal Ls. This also applies to... Figure 4 The embodiments shown will not be described in detail here.

[0037] In specific implementation, the digital control unit 400 performs the following: when the first detection signal Sc exceeds a threshold range, the slope of the change in the first detection signal Sc and the compensation coefficient k are weighted relative to the load prediction change signal Ls to obtain the loop compensation value. For example, the weight of the influence of the slope of the change in the first detection signal Sc and the compensation coefficient k on the loop compensation value M can be set to 0.6, and the weight of the influence of the load prediction change signal Ls on the loop compensation value M can be set to 0.4. Of course, this application does not limit the weighting ratio and can be determined according to the actual load and application scenario.

[0038] In practical applications, loads such as GPUs (Graphics Processing Units) and graphics cards can transmit their changing trends to the digital control unit 400 in advance. The first processing unit 410 can then obtain the loop compensation value M by combining the first detection signal Sc and the predicted load change signal Ls, making the loop compensation value M more accurate. In actual implementation, the GPU can transmit load changes to the first processing unit 410 in advance via the signal line of the PCIe power supply terminal.

[0039] Furthermore, such as Figures 3 to 5As shown, the fourth operational unit 440 in the voltage control loop of the power factor correction circuit 100 also receives a voltage detection signal Vs from the power factor correction circuit 100. In practical applications, the voltage detection signal Vs may include the power frequency AC input signal Vacin, and may also include other voltage signals required in the voltage control loop.

[0040] Furthermore, when the AC input voltage signal Vacin of the power factor correction circuit 100 crosses zero, the third arithmetic unit 430 performs the operation of superimposing the loop compensation value M onto the output of the voltage loop of the power factor correction circuit, or superimposing it onto the reference voltage signal Vref of the voltage loop of the power factor correction circuit. This allows for real-time correction of the output power of the power factor correction circuit 100 while ensuring a sinusoidal input current.

[0041] If the loop compensation value M is applied to the control loop during a period when the amplitude of the power frequency AC signal is not zero, it will cause a rapid change in the input current of the power factor correction circuit 100. This will result in the input current of the power factor correction circuit 100 not being sinusoidal within half a power frequency cycle, meaning the current does not follow the voltage, thus affecting the power factor of the power factor correction circuit 100. When the power frequency AC input voltage signal crosses zero, the loop compensation value M is superimposed on the control loop. This ensures that the input current of the power factor correction circuit 100 always follows the input voltage for the next half of the power frequency cycle, improves the smoothness of the input current of the power factor correction circuit 100, and guarantees the power factor of the power factor correction circuit 100.

[0042] In practical implementation, the aforementioned digital control unit 400 can be a DSP unit. Of course, any digital control unit applicable in the industry is also applicable to this application.

[0043] In practical implementation, the power factor correction circuit 100 and the main power conversion module 300 can be any applicable topology, such as an isolated converter or a non-isolated converter. For example, the power factor correction circuit 100 can be a traditional BOOST PFC, totem-pole PFC, H-bridge PFC, interleaved PFC, three-phase PFC, or three-level PFC topology. The main power conversion module 300 can be an LLC resonant converter.

[0044] In another embodiment of this application, both the power factor correction circuit 100 and the main power conversion module 300 are non-isolated converters, such as... Figures 3 to 5 As shown. The control unit 400 is implemented by a DSP unit, and the first arithmetic unit 410, the second arithmetic unit 420, the third arithmetic unit 430, the fourth arithmetic unit 440 and the control signal generation unit 450 are all executed by this DSP unit.

[0045] In a typical embodiment of this application, please refer to Figure 6 The schematic diagram of a power conversion device according to another embodiment of this application shows that the power factor correction circuit 100 is a non-isolated converter, such as a BOOST converter, and the main power conversion module 300 is an isolated converter, such as an LLC resonant converter. The primary side of the power factor correction circuit 100 and the main power conversion module 300 constitutes the primary-side circuit, and the secondary side of the main power conversion module 300 constitutes the secondary-side circuit. In this case, the control unit 400 includes a first DSP unit and a second DSP unit. The first DSP unit is a primary-side control unit used to control the switching transistors in the power factor correction circuit 100, and the second DSP unit is a secondary-side control unit used to control the switching transistors in the secondary-side circuit of the main power conversion module 300 and control the switching transistors in the primary-side circuit of the main power conversion module 300 through an isolation drive module.

[0046] Furthermore, when the first detection signal Sc is a signal from the secondary side of the main power conversion module 300, such as the first detection signal Sc being the output current or the output voltage of the main power conversion module 300, then the first arithmetic unit 410 is executed by the second DSP unit, and the second arithmetic unit 420, the third arithmetic unit 430, the fourth arithmetic unit 440 and the control signal generation unit 450 are executed by the first DSP unit, and the loop compensation value M is transmitted to the first DSP unit through the isolation transmission unit.

[0047] Furthermore, when the first detection signal Sc is a signal from the primary side of the main power conversion module 300, such as the frequency or duty cycle of the switching transistor in the primary side circuit of the main power conversion module 300, or the input current of the main power conversion module 300, then the first arithmetic unit 410, the second arithmetic unit 420, the third arithmetic unit 430, the fourth arithmetic unit 440 and the control signal generation unit 450 are all executed by the first DSP unit. At this time, there is no need for an isolation transmission unit to transmit signals, and the circuit is simple and fast.

[0048] In another embodiment of this application, please refer to Figure 7The schematic diagram of a power conversion device according to another embodiment of this application shows that the power factor correction circuit 100 is an isolated converter, and the main power conversion module 300 is a non-isolated converter. The primary side of the power factor correction circuit 100 constitutes the primary-side circuit, and the secondary side of the power factor correction circuit 100 and the main power conversion module 300 constitute the secondary-side circuit. In this case, the control unit 400 includes a first DSP unit and a second DSP unit. The first DSP unit is a primary-side control unit used to control the switching transistors on the primary side of the power factor correction circuit 100, and the second DSP unit is a secondary-side control unit used to control the switching transistors on the secondary side of the power factor correction circuit 100 and the switching transistors in the main power conversion module 300.

[0049] Furthermore, at this time, the first arithmetic unit 410, the second arithmetic unit 420 and the third arithmetic unit 430 are executed by the second DSP unit, the fourth arithmetic unit 440 and the control signal generation unit 450 are executed by the first DSP unit, and the output of the third arithmetic unit 430 is transmitted to the first DSP unit through the isolation transmission unit.

[0050] In practical implementation, for the embodiment where the digital control unit 400 also receives a load prediction change signal Ls from the load and obtains the loop compensation value M based on the first detection signal Sc and the load prediction change signal Ls, the load prediction change signal Ls from the load is usually discrete, and the loop compensation value M obtained based on the first detection signal Sc and the load prediction change signal Ls is also usually discrete, that is, the loop compensation value M includes multiple different compensation values.

[0051] One embodiment of this application also provides a control method for a power converter; please refer to [link to relevant documentation]. Figure 8 The flowchart shown here illustrates a control method for a power converter according to another embodiment of this application. Please refer to it in conjunction with... Figures 1 to 7 The power converter includes a power factor correction circuit 100, comprising at least one switch, an input terminal, and an output terminal. The input terminal receives a power frequency AC input signal Vacin, and the output terminal is connected to a DC bus 200. The power factor correction circuit 100 is used to perform power factor correction. A main power conversion module 300 includes at least one switch, an input terminal, and an output terminal. The input terminal is connected to the DC bus 200, and the output terminal is used to connect to a load. The main power conversion module 300 is used to perform power conversion on the electrical signal on the DC bus 200 to supply power to the load. The control method for the power converter provided in this application includes: S1: Detect the first detection signal Sc from the main power conversion module 300; S2: Determine whether the first detection signal Sc is within a threshold range. If yes, proceed to step S3; otherwise, proceed to step S4. S3: Output loop compensation value is 0, proceed to step S5; S4: The loop compensation value M is obtained based on the slope of the change in the first detection signal Sc and a compensation coefficient k; S5: The loop compensation value M is superimposed on the output of the voltage loop of the power factor correction circuit, or superimposed on the reference voltage signal Vref of the voltage loop of the power factor correction circuit, and the voltage loop of the power factor correction circuit outputs a voltage difference signal. S6: Obtain the current reference signal Iref based on the voltage difference signal and the voltage detection signal Vs from the power factor correction circuit; S7: Based on the current reference signal Iref and the current detection signal Is from the power factor correction circuit 100, output a switching control signal Cr to control the power factor correction circuit 100.

[0052] In one embodiment of this application, in step S5: when the power factor correction circuit's AC input voltage signal crosses zero, the loop compensation value is superimposed on the output of the voltage loop of the power factor correction circuit, or superimposed on the reference voltage signal of the voltage loop of the power factor correction circuit.

[0053] In one embodiment of this application, in step S1, a load prediction change signal from the load is also received; in step S4, the loop compensation value is obtained by matching the change slope of the first detection signal and the compensation coefficient k with the load prediction change signal in a certain weight ratio.

[0054] Its advantages and principles are the same as those of the power conversion device mentioned above, and will not be repeated here.

[0055] Although embodiments of the present disclosure and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the present disclosure as defined by the appended claims.

[0056] Furthermore, the scope of this application is not intended to be limited to the specific embodiments of the processes, machines, manufactures, compositions of matter, apparatuses, methods, and steps described in the specification. As will be readily understood by those skilled in the art from the disclosure of this publication, processes, machines, manufactures, compositions of matter, means, methods, or steps that perform substantially the same function, currently exist or will be developed or implemented thereafter, will yield substantially the same results as the corresponding embodiments described herein that are available according to this disclosure. Therefore, the appended claims are intended to include such processes, machines, manufactures, compositions of matter, apparatuses, methods, or steps within their scope.

Claims

1. A power conversion device, characterized in that, include: A power factor correction circuit includes at least one switching transistor, an input terminal, and an output terminal. The input terminal is used to receive a power frequency AC input signal, and the output terminal is connected to a DC bus. The power factor correction circuit is used to achieve power factor correction. The main power conversion module includes at least one switching transistor, an input terminal, and an output terminal. The input terminal is connected to the DC bus, and the output terminal is used to connect to the load. The main power conversion module is used to perform power conversion on the electrical signal on the DC bus to supply power to the load. The digital control unit receives a first detection signal from the main power conversion module and outputs a switching control signal to control the power factor correction circuit based on the first detection signal, wherein the first detection signal characterizes the state of the load. The digital control unit performs the following: A loop compensation value is obtained based on the first detection signal, and when the first detection signal exceeds a threshold range, the loop compensation value is obtained based on the slope of the change of the first detection signal and a compensation coefficient k; when the first detection signal is within the threshold range, the loop compensation value is 0. The switching control signal of the power factor correction circuit is output based on the loop compensation value and the second detection signal from the power factor correction circuit.

2. The power conversion device according to claim 1, characterized in that, The digital control unit also receives a load prediction change signal from the load, and obtains the loop compensation value based on the first detection signal and the load prediction change signal.

3. The power conversion device according to claim 2, characterized in that, The digital control unit performs the following: when the first detection signal exceeds a threshold range, it combines the slope of the change of the first detection signal and the compensation coefficient k with the load prediction change signal in a certain weight ratio to obtain the loop compensation value.

4. The power conversion device according to claim 1 or 3, characterized in that, The loop compensation value is superimposed on the output of the voltage loop of the power factor correction circuit, or superimposed on the reference voltage signal of the voltage loop of the power factor correction circuit.

5. The power conversion device according to claim 4, characterized in that, The digital control unit includes: The first processing unit obtains the loop compensation value based on the first detection signal; The second processing unit obtains a first voltage difference signal based on the DC bus voltage signal from the DC bus and the reference voltage signal; The third processing unit superimposes the loop compensation value onto the first voltage difference signal to obtain the second voltage difference signal; The fourth arithmetic unit obtains a current reference signal based on the second voltage difference signal and the voltage detection signal from the power factor correction circuit; The control signal generation unit outputs a switching control signal for controlling the power factor correction circuit based on the current reference signal and the current detection signal from the power factor correction circuit.

6. The power conversion device according to claim 4, characterized in that, The digital control unit includes: The first processing unit obtains the loop compensation value based on the first detection signal; The third arithmetic unit superimposes the loop compensation value onto the reference voltage signal to obtain the second reference voltage signal; The second processing unit obtains a voltage difference signal based on the DC bus voltage signal from the DC bus and the second reference voltage signal. The fourth arithmetic unit obtains a current reference signal based on the voltage difference signal and the voltage detection signal from the power factor correction circuit; The control signal generation unit outputs a switching control signal for controlling the power factor correction circuit based on the current reference signal and the current detection signal from the power factor correction circuit.

7. A control method for a power converter, wherein the power converter includes a power factor correction circuit, comprising at least one switching transistor, an input terminal, and an output terminal, the input terminal being used to receive a power frequency AC input signal, the output terminal being connected to a DC bus, and the power factor correction circuit being used to perform power factor correction; a main power conversion module, comprising at least one switching transistor, an input terminal, and an output terminal, the input terminal being connected to the DC bus, the output terminal being used to connect to a load, and the main power conversion module being used to perform power conversion on the electrical signal on the DC bus to supply power to the load, characterized in that... include: S1: Detect the first detection signal from the main power conversion module; S2: Determine whether the first detection signal is within a threshold range. If yes, proceed to step S3; otherwise, proceed to step S4. S3: Output loop compensation value is 0, proceed to step S5; S4: Obtain the loop compensation value based on the slope of the change in the first detection signal and a compensation coefficient k; S5: The loop compensation value is superimposed on the output of the voltage loop of the power factor correction circuit, or superimposed on the reference voltage signal of the voltage loop of the power factor correction circuit, and the voltage loop of the power factor correction circuit outputs a voltage difference signal. S6: Obtain a current reference signal based on the voltage difference signal and the voltage detection signal from the power factor correction circuit; S7: Output a switching control signal to control the power factor correction circuit based on the current reference signal and the current detection signal from the power factor correction circuit.

8. The control method for the power converter according to claim 7, characterized in that, In step S5: when the power factor correction circuit's AC input voltage signal crosses zero, the loop compensation value is superimposed on the output of the power factor correction circuit's voltage loop, or superimposed on the reference voltage signal of the power factor correction circuit's voltage loop.

9. The control method for a power converter according to claim 8, characterized in that, In step S1, a load prediction change signal from the load is also received; In step S4: The loop compensation value is obtained by matching the slope of the first detection signal and the compensation coefficient k with the load prediction change signal in a certain proportion.

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