A totem pole PFC inductor current correction method, system, medium and terminal

Abstract

The present invention provides a totem pole PFC inductor current correction method and system, comprising: adjusting the control coefficient of the PI current compensator in the control circuit and the change law of the high-frequency carrier amplitude; the adjusted control circuit generates a modulation wave; and the modulation wave is input into the power circuit to realize the correction of the inductor current waveform. The present invention realizes the correction and compensation of the inductor current waveform by changing the reference voltage and the control coefficient of the current regulator, so that the inductor current waveform is closer to a sine wave, and the current harmonic content is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the field of power electronics, and in particular to a totem pole PFC inductor current correction method, system, medium and terminal. Background Art

[0002] Power electronic converters powered by single-phase AC voltage play an important role in household appliances and other equipment. However, in practical applications, active power factor correction (PFC) technology or single-phase active power filtering (APF) technology is needed to suppress grid-side harmonic currents and improve grid-side power factor to meet the harmonic suppression standards specified in IEC61000-3-2 and IEC6100-3-12.

[0003] The power circuit and control circuit in the totem pole PFC, the power circuit includes two bridge arms, generally, one is a high frequency switching GaN FET or IGBT bridge arm, the other is a power frequency switching SiC FET or diode bridge arm, the control circuit includes an analog control circuit or a digital control circuit. Totem pole PFC is an active power factor correction circuit. Like other PFC circuits, the output capacitor voltage control can adopt PI controller, transconductance single zero unipolar controller, etc., and the inductor current control can adopt following control, single cycle control and hysteresis control, etc. For following control and single cycle control, since the instantaneous value of the voltage near the zero crossing of the grid voltage or input voltage is small, the grid current or input current has zero crossing distortion, resulting in a low grid side power factor and the appearance of higher harmonic currents, so zero crossing compensation is required.

[0004] For traditional bridge PFC, some literatures have proposed the concept of current compensation loop, which has achieved better current zero-crossing compensation. The compensation principle is: adding compensation to the original (after the absolute value of the sine wave) half-wave to expand the duty cycle near the zero-crossing of the grid voltage, thereby improving the input current crossover distortion. However, for totem pole PFC, there is no effective current zero-crossing compensation method, and the concept of traditional bridge PFC current compensation loop cannot be simply applied and needs to be redesigned. Summary of the invention

[0005] In view of the defects in the prior art, an object of the present invention is to provide a totem pole PFC inductor current correction method, system, medium and terminal.

[0006] According to one aspect of the present invention, a totem pole PFC inductor current correction method is provided, comprising:

[0007] Adjust the control coefficient of the PI current compensator in the control circuit and the change law of the high-frequency carrier amplitude;

[0008] The control circuit generates a compensated modulation wave;

[0009] Based on the compensated modulation wave and the high-frequency carrier with amplitude variation, the correction of the inductor current waveform of the power circuit is achieved.

[0010] Preferably, the control circuit comprises a voltage regulator, a current regulator, a switch pulse generator, an inductor link, an FRD link and a load link; wherein the output of the inductor link is used as the input of the current regulator to form a current inner loop compensation link;

[0011] The output of the load link is used as the input of the voltage regulator to form a voltage outer loop compensation link;

[0012] The high-frequency carrier amplitude of the switching pulse generator is adjustable;

[0013] The PI compensator control coefficient of the current regulator is adjustable.

[0014] Preferably, the control coefficient of the PI current compensator in the regulation control circuit includes:

[0015] Generate a sine wave u(1) of unit amplitude;

[0016] Set the minimum control coefficient a and the maximum control coefficient b of the PI compensator in the voltage regulator;

[0017] Calculate the control coefficient u(2) = a + (1-|u(1)|*b), the u(2) value should be between the lowest control coefficient a and the highest control coefficient b;

[0018] If the u(2) value is greater than the highest coefficient, the upper bound b value is taken as the final control coefficient of the PI compensator;

[0019] If the u(2) value is less than the minimum coefficient, the lower bound a value is taken as the final control coefficient of the PI compensator.

[0020] Preferably, the variation law of the high-frequency carrier amplitude in the regulating control circuit includes:

[0021] Generate a sine wave u(1) of unit amplitude;

[0022] Set the adjustment coefficient c, and c is between (0,1)

[0023] Calculate c*|u(1)|;

[0024] Calculate u(2)=(1-c)+c*|u(1)| as the value after the reference voltage amplitude changes.

[0025] Preferably, the control circuit generates a compensated modulated wave, comprising:

[0026] Extract the output point voltage of the voltage regulator of the voltage outer loop compensation link:

[0027] The output point voltage is multiplied by the final control coefficient to serve as the modulation wave input signal of the pulse generator.

[0028] Preferably, the control circuit generates a compensated modulated wave, comprising:

[0029] Extract high frequency triangular carrier utr with constant amplitude;

[0030] The utr and u(2) are multiplied together to form a high-frequency carrier input signal for the switching pulse generator.

[0031] Preferably, the correction of the inductor current waveform of the power circuit based on the compensated modulation wave and the high-frequency carrier with a changed amplitude includes:

[0032] The compensated modulation wave is compared with the high-frequency carrier wave with amplitude change to generate a PWM signal.

[0033] The PWM signal is sent to the power circuit after being driven;

[0034] The PWM signal drives the power switch in the power circuit to turn on and off, thereby correcting the inductor current waveform.

[0035] According to a second aspect of the present invention, a totem pole PFC inductor current correction system is provided, comprising:

[0036] A regulating module, wherein the regulating module regulates a control coefficient of a PI current compensator in a control circuit and a change rule of a high-frequency carrier amplitude;

[0037] A generating module, wherein the generating module controls the circuit to generate a compensated modulated wave;

[0038] A correction module is provided, wherein the correction module corrects the inductor current waveform of the power circuit based on the compensated modulation wave and the high-frequency carrier with amplitude variation.

[0039] According to a third aspect of the present invention, there is provided a terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor can be used to execute any one of the methods described, or to run the system described, when executing the program.

[0040] According to a fourth aspect of the present invention, there is provided a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, can be used to execute any of the methods described above, or to run the system described above.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The totem pole PFC inductor current correction method and system provided in the embodiments of the present invention utilizes the change of the reference voltage and the current regulator control coefficient to achieve correction compensation of the inductor current waveform, so that the inductor current waveform is closer to a sine wave, and the current harmonic content is effectively reduced.

[0043] (2) The totem pole PFC inductor current correction method and system provided in the embodiments of the present invention directly performs compensation in the output link of the voltage regulator and the input control coefficient link of the current regulator, thereby achieving correction of the inductor current waveform, and has the advantages of being simple, easy to operate, and highly reliable.

[0044] (3) The totem pole PFC inductor current correction method and system provided in the embodiments of the present invention can change the required coefficient in the correction link according to different needs, can adapt to different working conditions, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0046] Figure 1 is a flow chart of a totem pole PFC inductor current correction method in one embodiment;

[0047] Figure 2 is a structural diagram of a control circuit in a totem pole PFC inductor current correction method in an embodiment;

[0048] Figure 3 It is a flow chart of realizing adjustable control coefficient and adjustable carrier amplitude in a preferred embodiment;

[0049] Figure 4 is a structural diagram of a power circuit in a totem pole PFC inductor current correction method in a preferred embodiment;

[0050] Figure 5 1 is a grid-side current waveform diagram and an inductor current output waveform diagram when the inductor current correction method is not adopted in the embodiment of the present invention;

[0051] Figure 6 The grid-side current waveform diagram and the inductor current output waveform diagram after the inductor current correction method is adopted in the embodiment of the present invention. DETAILED DESCRIPTION

[0052] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0053] See also Figure 1 The present invention provides an embodiment, a totem pole PFC inductor current correction method, comprising:

[0054] S100, adjusting the control coefficient of the PI current compensator in the control circuit and the change rule of the high-frequency carrier amplitude;

[0055] S200, controlling the circuit to generate a compensated modulation wave;

[0056] S300, based on the modulated wave compensated in S200 and the high-frequency carrier wave with a changed amplitude, the inductor current waveform of the power circuit is corrected.

[0057] See also Figure 2 In one embodiment of the present invention, the control circuit in S100 includes a current inner loop compensation link, a voltage outer loop compensation link, a voltage regulator, a current regulator, a switch pulse generator, an inductor link, an FRD link, and a load link; wherein the output of the inductor link is used as the input of the current regulator to form a current inner loop compensation link; the output of the load link is used as the input of the voltage regulator to form a voltage outer loop compensation link; the high-frequency carrier amplitude of the switch pulse generator is adjustable; and the PI compensator control coefficient of the current regulator is adjustable.

[0058] See also Figure 3 In a preferred embodiment of the present invention, the process of adjusting the control coefficient of the PI current compensator in the control circuit in S100 is:

[0059] S11, generate a sine wave u(1) of unit amplitude;

[0060] S12, setting the lowest control coefficient a and the highest control coefficient b of the PI compensator in the voltage regulator;

[0061] S13, calculate the control coefficient u(2) = a + (1-|u(1)|*b), the value of u(2) should be between the lowest control coefficient a and the highest control coefficient b;

[0062] S14, if the u(2) value is greater than the highest coefficient, the upper bound b value is taken as the final control coefficient of the PI compensator;

[0063] S15, if the u(2) value is less than the minimum coefficient, the lower bound a value is taken as the final control coefficient of the PI compensator.

[0064] Among them, the generation process of the sine wave u(1) is to first detect the single-phase AC voltage, that is, the power supply voltage, and obtain the digitized single-phase AC voltage after digital analog-to-digital conversion, and then use the phase-locked loop program to obtain a sine wave of unit amplitude. In the above process, it can be seen from the calculation formula of u(2) that near the zero point of the grid voltage, the u(2) value is larger and reaches the b value. Near the peak point of the grid voltage, the u(2) value is smaller and reaches the a value. At other locations of the grid voltage, the u(2) value is between the a value and the b value, and the calculated value is the value.

[0065] See also Figure 3 In another preferred embodiment of the present invention, the process of adjusting the change law of the high-frequency carrier amplitude in S100 is:

[0066] S21, generate a sine wave u(1) of unit amplitude;

[0067] S22, set the adjustment coefficient c, and c is between (0,1)

[0068] S23, calculate c*|u(1)|;

[0069] S24, calculate u(2)=(1-c)+c*|u(1)| as the value after the reference voltage amplitude changes.

[0070] In a preferred embodiment of the present invention, based on the control coefficient adjusted in S100 and the change law of the high-frequency carrier amplitude, S200 is implemented. Figure 2 The control circuit principle process is: the output voltage u of the voltage outer loop compensation link o ′ and reference voltage U ref The difference is used as the input terminal V of the voltage regulator etr , the output terminal U of the voltage regulator ctr1 And network voltage signal u i After multiplication, subtract the output signal i of the current inner loop compensation link L ' as the input terminal I of the current regulator etr .

[0071] The output terminal u of the switching pulse generator i ′ and grid voltage instantaneous value u i The difference is used as the input signal of the inductor link, and the output signal of the inductor link is used as the input of the current inner loop compensation link and the input of the FRD link. The output ID1 of the FRD link is used as the input of the load link through the inductor current detection feedback transfer function HI(S). The output of the load link u o The output voltage is detected and the feedback transfer function Hv(S) is used as the input end of the voltage outer loop compensation link.

[0072] In a preferred embodiment, the above embodiment adjusts the high-frequency carrier amplitude variation law to generate the network voltage signal u i ″ and obtain the high-frequency carrier input signal of the switching pulse generator. Among them, the grid voltage signal u i ″ is generated by: implementing the above S21-S24 to obtain u(2) as the value after the reference voltage amplitude changes. i After that, the high-frequency triangular carrier with constant amplitude is extracted, and the two are multiplied together as the high-frequency carrier input signal u of the switching pulse generator. tr In this embodiment, the adjustment coefficient c is set to 0.75

[0073] In a preferred embodiment, the control coefficient of the PI current compensator in the above embodiment is used to generate the modulation wave input signal of the switch pulse generator. Specifically, the above S11-S15 are implemented to obtain the final control coefficient; then the output point voltage U of the voltage regulator in the voltage outer loop is extracted. ctr1 , the control coefficient is multiplied with it as the modulation wave input signal of the switching pulse generator. In this embodiment, the lowest control coefficient a=25 and the highest control coefficient b=75 of the PI compensator in the voltage regulator are set.

[0074] In a preferred embodiment of the present invention, S300 is implemented, the compensated modulated wave is compared with the high-frequency carrier wave with amplitude variation to generate a PWM signal, which is driven and sent to the power circuit to drive the power switch in the power circuit to turn on and off, thereby realizing the correction of the inductor current waveform.

[0075] In this embodiment, see Figure 4 , the power circuit includes an AC power supply u i , input filter capacitor C1 and totem pole PFC circuit. The AC power supply includes: a first output terminal and a second output terminal, wherein the first output terminal and the second output terminal constitute an AC power supply output terminal, and the output u i The first end of the input filter capacitor is connected to the first output end of the AC power supply, and the other end of the input filter capacitor is connected to the second output end of the AC power supply. The totem pole PFC circuit includes: an inductor L1, a first field effect transistor S1, a second field effect transistor S2, a third field effect transistor S3, a fourth field effect transistor S4, a first resistor unit and a second resistor unit;

[0076] The source of the first field effect transistor S1 is connected to the drain of the second field effect transistor S2; the source of the third field effect transistor S3 is connected to the drain of the fourth field effect transistor S4. The first end of the inductor L1 is connected to the live wire L of the AC power source L1, and the second end of the inductor L1 is connected to the node between the source of the first field effect transistor S1 and the drain of the second field effect transistor S2. The node between the source of the third field effect transistor S3 and the drain of the fourth field effect transistor S4 is connected to the AC power source u i The drain of the first field effect transistor S1 is connected to the drain of the third field effect transistor S3, the source of the second field effect transistor S2 is grounded, and the source of the fourth field effect transistor S4 is grounded. The first end of the first resistor unit is connected to the node between the drain of the first field effect transistor S1 and the drain of the third field effect transistor S3, the second end of the first resistor unit is connected to the first end of the second resistor unit, and the second end of the second resistor unit is grounded.

[0077] Based on the same inventive concept, other embodiments of the present invention further provide a totem pole PFC inductor current correction system, including:

[0078] An adjustment module, a generation module and a correction module; the adjustment module adjusts the control coefficient of the PI current compensator in the control circuit and the variation law of the high-frequency carrier amplitude; the generation module controls the circuit to generate a compensated modulation wave; the correction module realizes the correction of the inductor current waveform of the power circuit based on the compensated modulation wave and the high-frequency carrier with amplitude variation.

[0079] The various modules / units in the above examples of the present invention may specifically refer to the implementation techniques of the corresponding steps of the totem pole PFC inductor current correction method in the above embodiments, which will not be described in detail herein.

[0080] Based on the same inventive concept, other embodiments of the present invention also provide a terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor can be used to execute any one of the methods described, or to run the system described when executing the program.

[0081] Based on the same inventive concept, other embodiments of the present invention further provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, can be used to execute any of the methods described above, or to run the system described above.

[0082] In an application embodiment of the invention, the parameters are set as follows:

[0083] Input voltage: 220Vac@50Hz;

[0084] Output voltage: 385V;

[0085] Output power: several hundred watts to 3.3kW;

[0086] Switching frequency: 40kHz

[0087] Resistors R1, R2: 1MΩ;

[0088] Resistor R3: 25.8kΩ;

[0089] Diodes D1~D2: 1N4148;

[0090] Capacitor C1: 1.0μF;

[0091] Capacitor C2: 3x470μF;

[0092] Inductor L1: 250μH;

[0093] SiC FET S3, S4: 25A@85℃, 650V;

[0094] GaN FET S1, S2: 25A@85℃, 650V.

[0095] The corresponding inductor current waveform before and after correction is as follows: Figure 5 , Figure 6 As shown. It can be seen that this embodiment uses the change of the reference voltage and the current regulator control coefficient to achieve correction and compensation of the inductor current waveform, making the inductor current waveform closer to a sine wave, and effectively reducing the current harmonic content.

[0096] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various modifications or variations within the scope of the claims, which does not affect the essence of the present invention. The above preferred features can be used in any combination without conflicting with each other.

Claims

1. A totem pole PFC inductor current correction method, characterized in that: include: Adjust the control coefficient of the PI current compensator in the control circuit and the change law of the high-frequency carrier amplitude; The control circuit generates a compensated modulation wave; Correction of the inductor current waveform of the power circuit is achieved based on the compensated modulation wave and the high-frequency carrier with amplitude variation; The control circuit includes a voltage regulator, a current regulator, a switch pulse generator, an inductor link, an FRD link and a load link; wherein the output of the inductor link is used as the input of the current regulator to form a current inner loop compensation link; the output of the load link is used as the input of the voltage regulator to form a voltage outer loop compensation link; the high-frequency carrier amplitude of the switch pulse generator is adjustable; and the PI compensator control coefficient of the current regulator is adjustable; The control coefficient of the PI current compensator in the regulating control circuit includes: Generate a sine wave u(1) of unit amplitude; Set the minimum control coefficient a and the maximum control coefficient b of the PI compensator in the voltage regulator; Calculate the control coefficient u(2) = a + (1-|u(1)|*b), the u(2) value should be between the lowest control coefficient a and the highest control coefficient b; If the u(2) value is greater than the highest coefficient, the upper bound b value is taken as the final control coefficient of the PI compensator; If the u(2) value is less than the minimum coefficient, the lower bound a value is taken as the final control coefficient of the PI compensator; The high-frequency carrier amplitude variation law in the regulation control circuit includes: Generate a sine wave u(1) of unit amplitude; Set the adjustment coefficient c, and c is between (0,1) Calculate c*|u(1)|; Calculate u(2)=(1-c)+c*|u(1)| as the value after the reference voltage amplitude changes.

2. A totem pole PFC inductor current correction method according to claim 1, characterized in that: The control circuit generates a compensated modulated wave, comprising: Extracting the output point voltage of the voltage regulator of the voltage outer loop compensation link; The output point voltage is multiplied by the final control coefficient to serve as the modulation wave input signal of the pulse generator.

3. The totem pole PFC inductor current correction method according to claim 1, characterized in that: The control circuit generates a compensated modulated wave, comprising: Extract high frequency triangular carrier utr with constant amplitude; The utr and u(2) are multiplied together to form a high-frequency carrier input signal for the switching pulse generator.

4. The totem pole PFC inductor current correction method according to claim 1, characterized in that: The correction of the inductor current waveform of the power circuit based on the compensated modulation wave and the high-frequency carrier with a changed amplitude includes: The compensated modulation wave is compared with the high-frequency carrier wave with amplitude change to generate a PWM signal. The PWM signal is sent to the power circuit after being driven; The PWM signal drives the power switch in the power circuit to turn on and off, thereby correcting the inductor current waveform.

5. A totem pole PFC inductor current correction system, characterized in that: include: A regulating module, wherein the regulating module regulates a control coefficient of a PI current compensator in a control circuit and a change rule of a high-frequency carrier amplitude; A generating module, wherein the generating module controls the circuit to generate a compensated modulated wave; A correction module, wherein the correction module corrects the inductor current waveform of the power circuit based on the compensated modulation wave and the high-frequency carrier with a changed amplitude; The control circuit includes a voltage regulator, a current regulator, a switch pulse generator, an inductor link, an FRD link and a load link; wherein the output of the inductor link is used as the input of the current regulator to form a current inner loop compensation link; the output of the load link is used as the input of the voltage regulator to form a voltage outer loop compensation link; the high-frequency carrier amplitude of the switch pulse generator is adjustable; and the PI compensator control coefficient of the current regulator is adjustable; The control coefficient of the PI current compensator in the regulating control circuit includes: Generate a sine wave u(1) of unit amplitude; Set the minimum control coefficient a and the maximum control coefficient b of the PI compensator in the voltage regulator; Calculate the control coefficient u(2) = a + (1-|u(1)|*b), the u(2) value should be between the lowest control coefficient a and the highest control coefficient b; If the u(2) value is greater than the highest coefficient, the upper bound b value is taken as the final control coefficient of the PI compensator; If the u(2) value is less than the minimum coefficient, the lower bound a value is taken as the final control coefficient of the PI compensator; The high-frequency carrier amplitude variation law in the regulation control circuit includes: Generate a sine wave u(1) of unit amplitude; Set the adjustment coefficient c, and c is between (0,1) Calculate c*|u(1)|; Calculate u(2)=(1-c)+c*|u(1)| as the value after the reference voltage amplitude changes.

6. A terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, it can be used to execute the method described in any one of claims 1 to 4, or to run the system described in claim 5.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, it can be used to execute the method described in any one of claims 1 to 4, or to run the system described in claim 5.

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