A feedforward control method, device, apparatus and storage medium

Abstract

The application discloses a feedforward control method, which comprises the following steps: firstly, acquiring an input voltage value and an output voltage value of a system; then, calculating a duty cycle signal value according to the input voltage value, the output voltage value and a preset output voltage reference value; the output voltage value and the duty cycle are in reverse relationship; finally, controlling the turn-on and turn-off of a main switch tube of the system according to the duty cycle signal value. According to the input voltage value, the output voltage value and the preset output voltage reference value, the duty cycle signal value is calculated, the change direction of the duty cycle is opposite to the change direction of the output voltage, and thus, the voltage stabilization is realized through the feedforward control when the PFC is in an idle state.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a feedforward control method, device, equipment and storage medium. Background Technology

[0002] In systems where the reference signal is time-varying, and feedback cannot track it in a timely manner, feedforward control is an effective method to eliminate and reduce disturbances in the control system. Therefore, feedforward control is often used in power factor correction (PFC) circuits, which can effectively improve the ratio of effective power to apparent power at the power supply input.

[0003] In existing technologies, feedforward control is generally used as an additional auxiliary control, with feedback controlling the target quantity (such as current) and feedforward acting as an auxiliary control of the output voltage. When the PFC is operating under no-load conditions, the change in current under feedback control is not significant, resulting in a small current loop output. Therefore, the effect of the feedback loop is small, and control is basically achieved by feedforward. When the input remains constant, the duty cycle calculated by the traditional feedforward calculation formula is in the same direction as the output change, thus failing to achieve voltage regulation. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a feedforward control method, apparatus, device, and storage medium that enables voltage regulation via feedforward control when the PFC is unloaded.

[0005] The embodiments of this application disclose the following technical solutions:

[0006] In a first aspect, this application provides a feedforward control method, the method comprising:

[0007] Obtain the system's input and output voltage values;

[0008] The duty cycle signal value is calculated based on the input voltage value, the output voltage value, and the preset output voltage reference value; the output voltage value is inversely related to the duty cycle.

[0009] The main switch of the system is turned on and off based on the value of the duty cycle signal.

[0010] Optionally, after obtaining the value of the duty cycle signal, the method further includes:

[0011] Calculate the value of the complementary duty cycle signal based on the duty cycle signal;

[0012] The switching on and off of the secondary switch of the system is controlled based on the value of the complementary duty cycle signal.

[0013] Optionally, the formula for calculating the duty cycle signal value based on the input voltage value, the output voltage value, and the preset output voltage reference value is as follows:

[0014]

[0015] Where D represents the value of the duty cycle signal, V in This represents the value of the input voltage, V. out This represents the value of the output voltage, V. ref This indicates the output voltage reference value.

[0016] Optionally, the formula for calculating the value of the complementary duty cycle signal based on the duty cycle signal is as follows:

[0017]

[0018] Where D' represents the value of the complementary duty cycle signal, D represents the value of the duty cycle signal, and V in This represents the value of the input voltage, V. out This represents the value of the output voltage, V. ref This indicates the output voltage reference value.

[0019] Secondly, this application provides a feedforward control device, the device comprising: an acquisition module, a first calculation module, and a first control module;

[0020] The acquisition module is used to acquire the system's input voltage value and output voltage value;

[0021] The first calculation module is used to calculate the value of the duty cycle signal based on the input voltage value, the output voltage value, and a preset output voltage reference value; the output voltage value is inversely related to the duty cycle.

[0022] The first control module is used to control the on and off of the main switch of the system according to the value of the duty cycle signal.

[0023] Optionally, the device further includes: a second computing module and a second control module;

[0024] The second calculation module is used to calculate the value of the complementary duty cycle signal based on the duty cycle signal;

[0025] The second control module is used to control the on and off of the secondary switch of the system according to the value of the complementary duty cycle signal.

[0026] Optionally, the first calculation module is specifically used for:

[0027]

[0028] Where D represents the value of the duty cycle signal, V in This represents the value of the input voltage, V. out This represents the value of the output voltage, V. ref This indicates the output voltage reference value.

[0029] Optionally, the second calculation module is specifically used for:

[0030]

[0031] Where D' represents the value of the complementary duty cycle signal, D represents the value of the duty cycle signal, and V in This represents the value of the input voltage, V. out This represents the value of the output voltage, V. ref This indicates the output voltage reference value.

[0032] Thirdly, this application provides a feedforward control device, characterized in that it includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements the feedforward control method as described in any of the first aspects.

[0033] Fourthly, this application provides a computer-readable storage medium, characterized in that the computer-readable storage medium stores instructions that, when executed on a terminal device, cause the terminal device to perform the feedforward control method as described in any of the first aspects.

[0034] First, the system's input voltage and output voltage values ​​are acquired. Then, based on the input voltage, output voltage, and a preset output voltage reference value, the duty cycle signal is calculated. The output voltage and duty cycle are inversely related. Finally, the main switch of the system is controlled to turn on and off based on the value of the duty cycle signal.

[0035] Compared with the prior art, this application has the following beneficial effects:

[0036] The duty cycle signal is calculated based on the input voltage, output voltage, and preset output voltage reference value. The direction of change of the duty cycle is opposite to the direction of change of the output voltage. Therefore, voltage regulation is achieved through feedforward control when the PFC is unloaded. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 A flowchart of a feedforward control method provided in an embodiment of this application;

[0039] Figure 2 The flowchart of another feedforward control method provided in the embodiments of this application;

[0040] Figure 3 This is a schematic diagram of a feedforward control device provided in an embodiment of this application. Detailed Implementation

[0041] As described earlier, in current feedforward control, for the PWM control used in the main switch, the formula for calculating the duty cycle is:

[0042]

[0043] Where D represents the value of the duty cycle signal, V in This represents the value of the input voltage, V. out This represents the output voltage value. As shown in the formula above, there is a direct proportional relationship between the duty cycle signal and the output voltage; that is, the larger the duty cycle signal, the larger the output voltage; and the smaller the duty cycle signal, the smaller the output voltage. Therefore, when the PFC is unloaded, feedforward control cannot effectively regulate the voltage.

[0044] In view of this, this application provides a feedforward control method, which includes: acquiring the input voltage value and the output voltage value of the system; calculating the value of the duty cycle signal based on the input voltage value, the output voltage value and a preset output voltage reference value; the output voltage value and the duty cycle are inversely related; and controlling the on and off of the main switch of the system based on the value of the duty cycle signal.

[0045] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0046] See Figure 1 The figure is a flowchart of a feedforward control method provided in this application.

[0047] like Figure 1 As shown, the method includes:

[0048] S101: Obtain the system's input voltage and output voltage values.

[0049] The system can be a switching power supply system with PFC.

[0050] To suppress current waveform distortion and improve power factor, electrical appliances with higher power ratings (greater than 85W) and switching power supplies (capacitive loads) must employ PFC measures. There are two main types of PFC: active PFC and passive PFC.

[0051] Passive power factor correction (PFC) works by adding an inductor (with an appropriately selected inductance value) between the rectifier bridge and the filter capacitor. It utilizes the characteristic that the current in the inductor cannot change abruptly to smooth the fluctuations caused by the strong charging pulses of the capacitor, thus improving the distortion of the power supply current waveform. Furthermore, the voltage leading the current in the inductor compensates for the current leading the voltage in the filter capacitor, thereby improving power factor, electromagnetic compatibility, and electromagnetic interference. However, this simple, low-cost passive PFC has a relatively large output ripple, a low DC voltage across the filter capacitor, and poor current distortion correction and power factor compensation capabilities. Moreover, poor winding and core quality control of the inductor L can cause serious interference to the image and audio.

[0052] The basic principle of active PFC is to add a DC-DC chopper circuit between the rectifier circuit and the filter capacitor of the switching power supply. Since the output of this rectifier circuit is not directly connected to the filter capacitor for the power supply line, it presents itself as a purely resistive load, with its voltage and current waveforms in phase. The operation of the chopper circuit is also similar to that of a switching power supply. Therefore, an active PFC switching power supply is essentially a dual-switching power supply circuit.

[0053] The system's input voltage and output voltage can be directly obtained using an oscilloscope or other relevant instruments.

[0054] S102: Calculate the duty cycle signal value based on the input voltage value, the output voltage value, and the preset output voltage reference value; the output voltage value and the duty cycle are inversely related.

[0055] Optionally, the formula for calculating the duty cycle signal value based on the input voltage value, the output voltage value, and the preset output voltage reference value is as follows:

[0056]

[0057] Where D represents the value of the duty cycle signal, V in This represents the value of the input voltage, V. out This represents the value of the output voltage, V. ref This indicates the output voltage reference value. When V out Equal to V within a certain time period ref They assume the system is operating in a steady state.

[0058] When the system is operating in steady state, i.e., V out=V ref The duty cycle signal is controlled by the input voltage signal and changes as the input voltage signal changes. When the input voltage signal increases, the duty cycle signal D decreases; when the input voltage signal decreases, the duty cycle signal D increases. Therefore, the input voltage signal can be a DC voltage signal or an AC voltage signal.

[0059] When the system is operating in a transient state, when V out <V ref At that time, V out With V ref The greater the phase difference, the larger the duty cycle signal D, in V out Approaching V ref At that time, the trend of the duty cycle signal increasing decreases until the steady state V out No longer affecting the duty cycle signal D; when V out >V ref At that time, V out With V ref The greater the phase difference, the smaller the duty cycle signal D, in V out Approaching V ref At this time, the trend of the duty cycle signal decreasing is diminishing. Therefore, the feedforward control method provided in this embodiment can enable the system to transition from transient to steady state.

[0060] S103: Control the main switch of the system to turn on and off according to the value of the duty cycle signal.

[0061] The value of the duty cycle signal can be used to control the main pulse width modulation (PWM) signal, which is used to control the main switch transistor. In turn, the main switch transistor is controlled by the main PWM signal.

[0062] The duty cycle signal is calculated based on the input voltage, output voltage, and preset output voltage reference value. The direction of change of the duty cycle is opposite to the direction of change of the output voltage. Therefore, voltage regulation is achieved through feedforward control when the PFC is unloaded.

[0063] See Figure 2 The figure is a flowchart of a feedforward control method provided in this application.

[0064] like Figure 2 As shown, the method includes:

[0065] S201: Obtain the system's input voltage and output voltage values.

[0066] The system's input voltage and output voltage can be directly obtained using an oscilloscope or other relevant instruments.

[0067] S202: Calculate the duty cycle signal value based on the input voltage value, output voltage value, and preset output voltage reference value; the output voltage value and the duty cycle are inversely related.

[0068] S203: Calculate the value of the complementary duty cycle signal based on the duty cycle signal.

[0069] Optionally, the formula for calculating the value of the complementary duty cycle signal based on the duty cycle signal is as follows:

[0070]

[0071] Where D' represents the value of the complementary duty cycle signal, D represents the value of the duty cycle signal, and V in This represents the value of the input voltage, V. out This represents the value of the output voltage, V. ref This indicates the output voltage reference value.

[0072] Complementary duty cycles can indirectly control the main PWM to achieve duty cycle signal control. If the PWM signal of the secondary switch is complementary to the PWM signal of the main switch, the complementary duty cycle can directly control the secondary switch to achieve duty cycle signal control.

[0073] S204: The duty cycle signal controls the on and off of the main switch, and the complementary duty cycle signal controls the on and off of the auxiliary switch.

[0074] The duty cycle signal value can be used to control the PWM signal that controls the main switch, thereby controlling the main switch; the complementary duty cycle signal value can be used to control the PWM signal that controls the secondary switch, thereby controlling the secondary switch.

[0075] By controlling the main switch with the duty cycle signal, and indirectly controlling the main switch with the complementary duty cycle (if the PWM signal of the auxiliary switch is complementary to the PWM signal of the main switch, the complementary duty cycle can directly control the auxiliary switch to achieve duty cycle signal control), the system can transition from transient operation to steady state more quickly.

[0076] See Figure 3 The figure is a schematic diagram of the structure of a feedforward control device provided in this application.

[0077] like Figure 3 As shown, the device includes: an acquisition module 301, a first calculation module 302, and a first control module 303;

[0078] The acquisition module 301 is used to acquire the input voltage value and the output voltage value of the system;

[0079] The first calculation module 302 is used to calculate the value of the duty cycle signal based on the input voltage value, the output voltage value, and a preset output voltage reference value; the output voltage value is inversely related to the duty cycle.

[0080] The first control module 303 is used to control the on and off of the main switch of the system according to the value of the duty cycle signal.

[0081] Optionally, the feedforward control device provided in this application further includes: a second calculation module and a second control module;

[0082] The second calculation module is used to calculate the value of the complementary duty cycle signal based on the duty cycle signal;

[0083] The second control module is used to control the on and off of the auxiliary switch based on the value of the complementary duty cycle signal.

[0084] The first calculation module is specifically used for:

[0085]

[0086] Where D represents the value of the duty cycle signal, V in This represents the value of the input voltage, V. out This represents the value of the output voltage, V. ref This indicates the output voltage reference value.

[0087] The second calculation module is specifically used for:

[0088]

[0089] Where D' represents the value of the complementary duty cycle signal, D represents the value of the duty cycle signal, and V in This represents the value of the input voltage, V. out This represents the value of the output voltage, V. ref This indicates the output voltage reference value.

[0090] When the system is operating in steady state, i.e., V out =V ref The duty cycle signal is controlled by the input voltage signal and changes as the input voltage signal changes. When the input voltage signal increases, the duty cycle signal D decreases; when the input voltage signal decreases, the duty cycle signal D increases. Therefore, the input voltage signal can be a DC voltage signal or an AC voltage signal.

[0091] When the system is operating in a transient state, when V out <V ref At that time, V out With V ref The greater the phase difference, the larger the duty cycle signal D, in V out Approaching Vref At that time, the trend of the duty cycle signal increasing decreases until the steady state V out No longer affecting the duty cycle signal D; when V out >V ref At that time, V out With V ref The greater the phase difference, the smaller the duty cycle signal D, in V out Approaching V ref At this time, the trend of the duty cycle signal decreasing is diminishing. Therefore, the feedforward control method provided in this embodiment can enable the system to transition from transient to steady state.

[0092] The duty cycle signal value can be used to control the PWM signal that controls the main switch, thereby controlling the main switch; the complementary duty cycle signal value can be used to control the PWM signal that controls the secondary switch, thereby controlling the secondary switch.

[0093] Using a duty cycle signal to control the main switch, and a complementary duty cycle to indirectly control the main switch (if the PWM signal of the auxiliary switch is complementary to the PWM signal of the main switch, the complementary duty cycle can directly control the auxiliary switch to achieve duty cycle signal control), the system can transition from transient operation to steady state more quickly.

[0094] This application provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the feedforward control method described in this application.

[0095] In practical applications, the computer-readable storage medium can be any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. For example, a computer-readable storage medium can be, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this embodiment, the computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0096] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, which can send, propagate, or transmit programs for use by or in connection with an instruction execution system, apparatus, or device.

[0097] Program code contained on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0098] Computer program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as "C" or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0099] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments. The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separate. The components indicated as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment solution according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0100] The above description is merely one specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A feedforward control method, characterized in that, The method includes: Obtain the system's input and output voltage values; The duty cycle signal value is calculated based on the input voltage value, the output voltage value, and the preset output voltage reference value; the output voltage value is inversely related to the duty cycle. The main switch of the system is turned on and off according to the value of the duty cycle signal; The formula for calculating the duty cycle signal value based on the input voltage value, the output voltage value, and the preset output voltage reference value is as follows: ； Where D represents the value of the duty cycle signal. This indicates the value of the input voltage. This indicates the value of the output voltage. This indicates the output voltage reference value.

2. The method as described in claim 1, characterized in that, After obtaining the value of the duty cycle signal, the method further includes: Calculate the value of the complementary duty cycle signal based on the duty cycle signal; The switching on and off of the secondary switch of the system is controlled based on the value of the complementary duty cycle signal.

3. The method as described in claim 2, characterized in that, The formula for calculating the value of the complementary duty cycle signal based on the duty cycle signal is as follows: ； in, This represents the value of the complementary duty cycle signal. This indicates the value of the duty cycle signal. This indicates the value of the input voltage. This indicates the value of the output voltage. This indicates the output voltage reference value.

4. A feedforward control device, characterized in that, The device includes: an acquisition module, a first calculation module, and a first control module; The acquisition module is used to acquire the system's input voltage value and output voltage value; The first calculation module is used to calculate the value of the duty cycle signal based on the input voltage value, the output voltage value, and a preset output voltage reference value; the output voltage value is inversely related to the duty cycle. The first control module is used to control the on and off of the main switch of the system according to the value of the duty cycle signal; Specifically, the first calculation module is used to calculate the value of the duty cycle signal according to the following formula: ； Where D represents the value of the duty cycle signal. This indicates the value of the input voltage. This indicates the value of the output voltage. This indicates the output voltage reference value.

5. The apparatus as described in claim 4, characterized in that, The device further includes: a second computing module and a second control module; The second calculation module is used to calculate the value of the complementary duty cycle signal based on the duty cycle signal; The second control module is used to control the on and off of the secondary switch of the system according to the value of the complementary duty cycle signal.

6. The apparatus of claim 5, wherein the second computing module is specifically used for: ； in, This represents the value of the complementary duty cycle signal. This indicates the value of the duty cycle signal. This indicates the value of the input voltage. This indicates the value of the output voltage. This indicates the output voltage reference value.

7. A feedforward control device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the feedforward control method as described in any one of claims 1 to 3.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores instructions that, when executed on a terminal device, cause the terminal device to perform the feedforward control method as described in any one of claims 1 to 3.

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