WO2013091358A1

WO2013091358A1 - Power factor compensation circuit applied to peak current control

Info

Publication number: WO2013091358A1
Application number: PCT/CN2012/076971
Authority: WO
Inventors: 葛良安; 姚晓莉
Original assignee: 英飞特电子（杭州）股份有限公司
Priority date: 2011-12-20
Filing date: 2012-06-15
Publication date: 2013-06-27
Also published as: CN103178704A; CN103178704B

Abstract

A power factor compensation circuit applied to peak current control. The current peak of a main switch tube in the circuit does not change as the input voltage changes. It includes: a drive control module (200), a current control module (100) and a power factor compensation module (400). The current control module (100) is used for controlling the current of a main switch tube in a main circuit (300). The drive control module (200) is used for controlling the switch state of the main switch tube according to a signal sent by the current control module (100). The power factor compensation module (400) is used for sampling an input voltage Vdc or sampling a drive signal of the main switch tube in the main circuit (300) or sampling a current signal of the main switch tube; and compensating the sampled signal into the current control module (100), so that the current peak of the main switch tube increases and the current peak increment of the main switch tube is maximum at the input voltage Vdc peak and minimum when the input voltage Vdc is zero. The circuit can improve the waveform of the input current, so that the waveform distortion degree of the input current reduces, and the power factor of the circuit is improved.

Description

Power factor compensation circuit suitable for peak current control

This application claims priority to Chinese Patent Application No. 201110430944.9, entitled "A Power Factor Compensation Circuit for Peak Current Control", filed on December 20, 2011, the entire disclosure of which is incorporated by reference. Combined in this application.

Technical field

The invention relates to the technical field of power factor compensation, in particular to a power factor compensation circuit suitable for peak current control.

Background technique

Referring to Figure 1, the figure is a schematic diagram of a prior art peak current control circuit.

In the current control module 100, the current of the switch S1 in the main circuit 300 is sampled by the sampling resistor Rs, which forms a voltage Vs on Rs.

Vs input integrated op amp (or comparator) U1 inverting input, control signal Vr input to the integrated op amp (or comparator) U1 non-inverting input, and the control signal Vr is not related to the input voltage Vdc; U1 will Vs Compared with Vr, when the peak value of Vs is equal to Vr, U1 outputs a signal to the drive control module 200, so that the drive signal outputted by the drive control module 200 turns off the switch S1.

In the above circuit, since the signal for controlling the switch S1 to be turned off is realized by controlling the current peak of the switch S1, this control mode is called peak current control.

The control of the circuit output current Io is realized by controlling the current peak of the switch S1. In the peak current control circuit, the waveforms of the current sampling signal Vs and the control signal Vr of the switching transistor S1 are as shown in FIG.

The slope of the current signal of the switch S1 is related to the input voltage Vdc, that is, when the instantaneous value of the input voltage Vdc is high, the slope of the current signal is large; when the instantaneous value of the input voltage Vdc is low, the slope of the current signal is small.

Since the peak value of the current sampling signal Vs of the switch S1 is equal to the control signal Vr, and the amplitude of the control signal Vr does not change with the change of the input voltage Vdc, according to the relationship between the slope of the current signal and the input voltage Vdc, it is obtained: When the instantaneous value of the input voltage Vdc is high, the slope of the current signal is large, and the on-time Ton of S1 is small; conversely, when the instantaneous value of the input voltage Vdc is low, the slope of the current signal is small, and the on-time Ton of S1 is smaller. Big. The off time Toff of the switch S1 is not related to the input voltage Vdc. The input current Iin of the main circuit 300 is the average current of the switch S1. When the output power of the main circuit is constant, the waveforms of the input current Iin of the main circuit 300 and the input voltage Vdc of the main circuit 300 are as shown in the figure.

3 is shown.

It can be seen from Fig. 3 that the waveform of Iin is concave near the peak of Vdc, and the waveform of the input current Iin in the peak current control circuit does not follow the waveform of the input voltage Vdc, so that the input current waveform before the rectifier bridge BD Nor does it follow the waveform of the input voltage Vin, so the power factor of the circuit is also low.

In summary, how to improve the power factor in the prior art peak current control circuit is a technical problem that those skilled in the art need to solve.

Summary of the invention

The technical problem to be solved by the present invention is to provide a power factor compensation circuit suitable for peak current control, which can improve the power factor of the peak current control circuit.

The invention provides a power factor compensation circuit suitable for peak current control. The main circuit input current Iin in the peak current controlled power factor compensation circuit has a minimum peak value at the input voltage Vdc and is maximum before and after the input voltage Vdc crosses zero, including : drive control module, current control module and power factor compensation module;

The current control module is configured to control a current of a main switch tube in the main circuit;

The driving control module is configured to control a switching state of the main switching tube according to a signal sent by the current control module;

The power factor compensation module is configured to sample the input voltage Vdc, or to drive a driving signal of the main switch tube in the main circuit, or to sample a current signal of the main switch tube; and compensate the sampling signal to the current control module, so that The peak current of the main switch tube is increased, and the current peak increase amount of the main switch tube is maximum at the peak value of the input voltage Vdc, and is minimum when the input voltage Vdc is zero.

Preferably, when the power factor compensation module is used to sample the driving signal of the switch tube in the main circuit or the current signal of the main switch tube, the sampling signal is compensated into the current control module, specifically:

The power factor compensation module filters the sampled signal and inputs it to the current control module.

Preferably, when the power factor compensation module samples the driving signal of the main switch tube, the power The factor compensation module includes: a first resistor and a first capacitor;

One end of the first resistor is connected to an output end of the driving control module, and the other end of the first resistor is grounded through a first capacitor;

The common end of the first resistor and the first capacitor is connected to the current control module as an output of the power factor compensation module.

The power factor compensation module filters and isolates the sampled signal and inputs it into the current control module.

Preferably, when the power factor compensation module samples the driving signal of the main switch, the power factor compensation module includes: a first resistor, a first capacitor, and a second capacitor;

One end of the first resistor is connected to an output end of the driving control module, and the other end of the first resistor is grounded through a first capacitor, and the other end of the first resistor is connected to one end of the second capacitor, the second capacitor The other end is connected to the current control module as an output of the power factor compensation module.

Preferably, the current control module includes: a first sampling resistor, a third resistor, a seventh resistor, and an operational amplifier;

One end of the main switch tube is grounded through the first sampling resistor, and the current signal of the main switch tube is obtained by detecting the voltage on the first sampling resistor;

The non-inverting input terminal of the operational amplifier is connected to the control signal; the inverting input terminal of the operational amplifier is connected to one end of the first sampling resistor through a seventh resistor, and the other end of the first sampling resistor is grounded; meanwhile, the inverse of the operational amplifier The phase input terminal is connected to the output end of the power compensation module through a third resistor;

The output of the operational amplifier is connected to the drive control module;

The drive control module outputs a drive signal to turn off the main switch when the signal of the inverting input of the operational amplifier is equal to the control signal of the non-inverting input.

Preferably, when the power factor compensation module samples the input voltage Vdc, the sampling signal is compensated into the current control module, specifically:

The power factor compensation module directly inputs the sampling signal into the current control module. Preferably, when the power factor compensation module samples the input voltage Vdc, the current control module includes: a first sampling resistor, a second resistor, a fourth resistor, and an operational amplifier;

The inverting input terminal of the operational amplifier is grounded through the first sampling resistor; the non-inverting input terminal of the operational amplifier is connected to the control signal through the fourth resistor, and the non-inverting input terminal of the operational amplifier is connected to the output end of the power factor compensation module through the second resistor;

The drive control module outputs a drive signal to turn off the main switch when the signal at the non-inverting input of the operational amplifier is equal to the signal at the inverting input.

Preferably, the power factor compensation module includes: a fifth resistor and a sixth resistor;

The fifth resistor and the sixth resistor are connected in series, and are connected in parallel with the input voltage Vdc;

The common ends of the fifth resistor and the sixth resistor serve as outputs of the power factor compensation module. Preferably, when the power factor compensation module samples the current signal of the main switch tube, the second sampling resistor is connected in series with the main switch tube, and the two input ends of the power factor compensation module are respectively connected to the second sampling Both ends of the resistor to sample the current signal of the main switch;

The current control module includes: a first sampling resistor, a third resistor, a seventh resistor, and an operational amplifier;

One end of the main switch tube is connected to one end of the first sampling resistor through a seventh resistor, the first sampling resistor is grounded, and a current signal of the main switch tube is obtained by detecting a voltage on the first sampling resistor; the operational amplifier The non-inverting input terminal is connected to the control signal; the inverting input terminal of the operational amplifier is grounded through the first sampling resistor; and the inverting input terminal of the operational amplifier is connected to the output end of the power factor compensation module through the third resistor;

The drive control module outputs a drive signal to turn off the main switch when the control signal of the non-inverting input of the operational amplifier is equal to the signal of the inverting input.

Preferably, the main circuit is an isolated circuit or a non-isolated circuit.

Preferably, the main circuit is a Buck circuit, including: a freewheeling diode, an inductor, and the main switch; One end of the main switch tube is connected to the anode of the freewheeling diode, the cathode of the freewheeling diode is connected to the positive end of the input voltage Vdc and the positive end of the output voltage, and the other end of the main switch tube is grounded through the first sampling resistor;

The anode of the freewheeling diode is connected to the negative terminal of the output voltage through the inductor.

Compared with the prior art, the present invention has the following advantages:

The power factor compensation circuit suitable for peak current control provided by the invention compensates the current of the main switch tube to increase the current peak value of the main switch tube, and maximizes the peak increase amount at the Vdc peak value, when the Vdc crosses zero The smallest. Thus, the waveform of the input current of the main circuit can be improved, so that the waveform of the input current of the main circuit is not recessed as much as possible near the peak value of Vdc, and the recessed portion of the prior art is filled. This reduces the distortion of the input current waveform and increases the power factor of the circuit.

DRAWINGS

1 is a schematic diagram of a peak current control circuit in the prior art;

2 is a waveform diagram of a current sampling signal Vs and a control signal Vr of the switching tube of FIG. 1; FIG. 3 is a waveform diagram of an input current Iin and an input voltage Vdc of FIG.

4 is a schematic diagram of Embodiment 1 of a power factor compensation circuit suitable for peak current control provided by the present invention;

5 is a schematic diagram of Embodiment 2 of a power factor compensation circuit suitable for peak current control provided by the present invention;

Figure 6 is a waveform diagram corresponding to the embodiment provided in Figure 5;

7 is a schematic diagram of Embodiment 3 of a power factor compensation circuit suitable for peak current control provided by the present invention;

8 is a schematic diagram of Embodiment 4 of a power factor compensation circuit suitable for peak current control provided by the present invention;

9 is a schematic diagram of Embodiment 5 of a power factor compensation circuit suitable for peak current control provided by the present invention;

10 is a schematic diagram of Embodiment 6 of a power factor compensation circuit suitable for peak current control provided by the present invention;

Figure 11 is a waveform diagram corresponding to Figure 10; 12 is a schematic diagram of Embodiment 7 of a power factor compensation circuit suitable for peak current control provided by the present invention;

Figure 13 is a schematic diagram of an eighth embodiment of a power factor compensation circuit suitable for peak current control provided by the present invention.

detailed description

The above described objects, features and advantages of the present invention will become more apparent from the aspects of the appended claims.

Referring to FIG. 4, the figure is a schematic diagram of a first embodiment of a power factor compensation circuit suitable for peak current control according to the present invention.

The present invention provides a power factor compensation circuit suitable for peak current control. The peak current of the main switch tube in the power factor compensation circuit of the peak current control does not change with the change of the input voltage, and includes: a main circuit 300 and a drive control module 200. , current control module 100 and power factor compensation module 400;

The current control module 100 is configured to control a current of a main switch tube in the main circuit;

The driving control module 200 is configured to control a switching state of the main switch according to a signal sent by the current control module 100;

The power factor compensation module 400 is configured to sample the input voltage Vdc, or sample the driving signal of the main switch tube in the main circuit, or sample the current signal of the main switch tube; compensate the sampling signal to the current control module 100, The current peak of the main switch tube is increased, and the current peak increase amount of the main switch tube is maximized at the peak value of the input voltage Vdc, and is minimized when the input voltage Vdc crosses zero.

The present invention compensates for the current of the main switching transistor to increase the current peak value of the main switching transistor, and maximizes the peak value at the Vdc peak value and the minimum at the Vdc zero crossing. In this way, the waveform of the input current can be improved so that the waveform of the input current is not recessed as close as possible to the peak value of Vdc, and fills the recessed portion of the prior art. This reduces the distortion of the input current waveform and increases the power factor of the circuit.

Here, it should be noted that the input voltage Vdc in the present invention is a waveform obtained by rectifying the sinusoidal alternating voltage Vin, that is, Vdc is in phase with the sinusoidal alternating voltage Vin, and the frequency of Vdc is twice the frequency of Vin. Typically, if the sinusoidal alternating voltage Vin is a 50 Hz grid voltage, the input voltage Vdc is a sinusoidal half-wave voltage of 100 Hz. It should be noted that the power factor compensation circuit provided by the present invention is applicable to the input current lin of the main circuit, and the peak value of the input voltage Vdc is the smallest, and is maximum before and after the input voltage Vdc crosses zero, that is, the input current lin applied to the main circuit is The waveform during the half cycle of the AC power source is recessed. In the circuit in which the main circuit is controlled by the peak current, when the on-time control mode of the switch tube is critical control, or the control period in which the switching period Ts is relatively constant or absolutely constant, or the switching period Ts is maximum near the peak value of the input voltage Vdc In the case of the zero-crossing minimum control mode, the waveform of the input current lin is recessed.

It should be noted that the input circuit lin of the main circuit is maximum before and after the input voltage Vdc crosses zero, and the limit is defined as the maximum before and after the Vdc zero crossing, and the maximum limit of lin when Vdc is zero crossing is because: Vdc is zero. When there is no voltage in the circuit, there is no current, that is, lin is zero. Since the circuit has a certain working dead zone in actual application, when Vdc is zero, the lin is zero between cells before and after Vdc zero crossing. , that is, the work dead zone. However, outside the working dead zone, lin is the largest before and after the Vdc zero crossing. For details, refer to the lin waveform shown in Figure 3.

The working principle of the power factor compensation circuit provided by the present invention will be described below in conjunction with a specific circuit diagram.

Referring to FIG. 5, the figure is a schematic diagram of a second embodiment of a power factor compensation circuit suitable for peak current control according to the present invention.

The power factor compensation circuit provided in this embodiment, wherein the power factor compensation module 400 is used to sample the driving signal of the main switch S1.

The current control module 100 includes: a first sampling resistor Rsl, a third resistor R3, a seventh resistor R7, and an operational amplifier U1;

One end of the main switch S1 is grounded through the first sampling resistor Rs1 (the "ground" mentioned in the present invention is a reference signal end, that is, the output negative end of the rectifier bridge BD), by detecting the first sampling resistor The voltage on Rsl obtains the current signal of the main switch S1;

The non-inverting input terminal of the operational amplifier U1 is connected to the control signal Vr; the inverting input terminal of the operational amplifier U1 is connected to the first sampling resistor Rsl-terminal through the seventh resistor R7, and the other end of the first sampling resistor Rs1 is grounded; meanwhile, the operational amplifier The inverting input terminal of U1 is connected to the output end of the power compensation module 400 through a third resistor R3;

The output of the operational amplifier U1 is connected to the drive control module 200;

When the signal Vs' of the inverting input of the operational amplifier U1 is equal to the non-inverting input When the signal Vr is controlled, the drive control module 200 outputs a drive signal to turn off the main switch S1. Where Vs' is the superposition of the voltage and power compensation module 400 output signal Vxi on Rsl. The main function of the power compensation module 400 is to filter the drive signal output by the drive control module 200.

Since the voltage on Rsl is superimposed on Vxi and input to the inverting input terminal of U1, for the current signal of the main switch S1, the compensation amount Vxi is the smallest near the peak value of the input voltage Vdc, and the peak value of the current signal of the main switch S1 is increased. The maximum compensation amount Vxi is the largest near the zero-crossing of the input voltage Vdc, and the peak increase amount of the main switch S1 is the smallest, that is, the increase amount Iin of the input current Iin' before the compensation is smaller than the peak value of the input voltage Vdc. The largest, the smallest near the zero crossing of Vdc, the waveform is shown in Figure 6.

Referring to FIG. 7, the figure is a schematic diagram of a third embodiment of a power factor compensation circuit suitable for peak current control according to the present invention.

Figure 7 is a diagram showing the specific structure of the power factor compensation module 400 on the basis of Figure 5.

When the power factor compensation module 400 samples the driving signal of the main switch, the power factor compensation module 400 includes: a first resistor R1 and a first capacitor C1;

One end of the first resistor R1 is connected to the output end of the driving control module 200, and the other end of the first resistor R1 is grounded through the first capacitor C1;

The common terminal of the first resistor R1 and the first capacitor C1 is connected to the current control module 100 as an output of the power factor compensation module 400.

R1 and C1 in the power factor compensation module 400 filter the drive signal output from the drive control module 200 and supply it to the current control module 100.

Referring to FIG. 8, the figure is a schematic diagram of a fourth embodiment of a power factor compensation circuit suitable for peak current control according to the present invention.

Figure 8 is a diagram showing the specific structure of the power factor compensation module 400 on the basis of Figure 5 .

When the power factor compensation module 400 samples the driving signal of the main switch, the power factor compensation module 400 includes: a first resistor R1, a first capacitor C1, and a second capacitor C2;

One end of the first resistor R1 is connected to the output end of the driving control module 200, the other end of the first resistor R1 is grounded through the first capacitor C1, and the other end of the first resistor R1 is connected to the second capacitor C2. One end of the second capacitor C2 serves as the input of the power factor compensation module 400 The current control module 100 is connected to the outlet.

R1 and C1 in the power factor compensation module 400 filter the driving signal outputted by the driving control module 200, and then perform DC blocking processing on the filtered signal through C2, and send it to the current control module 100. After the DC blocking process, the parameters of other components in the original circuit do not need to be changed, and the filter blocking circuit can directly act on the current control module 100.

The embodiment shown in Fig. 5, Fig. 7 and Fig. 8 is that the power factor compensation module 400 detects the drive signal outputted by the drive control module 200, that is, detects the drive signal of the main switch S1.

The following describes an embodiment of the power factor compensation module sampling the current signal of the main switch.

Referring to FIG. 9, FIG. 9 is a schematic diagram of Embodiment 5 of a power factor compensation circuit suitable for peak current control according to the present invention.

When the power factor compensation module 400 samples the current signal of the main switch S1, the second sampling resistor Rs2 is connected in series with the main switch S1, and the two input ends of the power factor compensation module 400 are respectively connected. Two sampling resistors Rs2, to sample the current signal of the main switch S1; the current control module 100 includes: a first sampling resistor Rsl, a third resistor R3, a seventh resistor R7 and an operational amplifier U1;

One end of the main switch S1 is grounded through the first sampling resistor Rs1, and the current signal of the main switch S1 is obtained by detecting the voltage on the first sampling resistor Rs1;

The non-inverting input terminal of the operational amplifier U1 is connected to the control signal Vr; the inverting input terminal of the operational amplifier U1 is connected to the first sampling resistor Rsl-terminal through the seventh resistor R7, and the other end of the first sampling resistor Rs1 is grounded; meanwhile, the operational amplifier The inverting input terminal of U1 is connected to the output end of the power factor compensation module 400 through a third resistor R3;

When the signal of the inverting input terminal of the operational amplifier U1 is equal to the control signal Vr of the non-inverting input terminal, the drive control module 200 outputs a driving signal to turn off the main switch S1.

In this embodiment, the power factor compensation module 400 filters the sampled S1 current signal, and sends the filtered signal Vxi as an output signal to the current control module 100.

Since the filtered signal of the current sampling signal in the main switch S1 is similar to the filtered signal of the driving signal of the main switch S1, the working principle of the embodiment is the same as that of the embodiment shown in FIG. No longer. The following describes an embodiment of the power factor compensation module sampling the current signal of the main switch. Referring to FIG. 10, the figure is a schematic diagram of Embodiment 6 of a power factor compensation circuit suitable for peak current control according to the present invention.

When the power factor compensation module 400 samples the input voltage Vdc, the current control module 100 includes: a first sampling resistor Rs1, a second resistor R2, a fourth resistor R4, and an operational amplifier U1; one end of the main switch S1 Grounding the first sampling resistor Rs1, and obtaining a current signal of the main switch S1 by detecting a voltage on the first sampling resistor Rs1;

The inverting input terminal of the operational amplifier U1 is grounded through the first sampling resistor Rs1; the non-inverting input terminal of the operational amplifier U1 is connected to the control signal Vr through the fourth resistor R4, and the non-inverting input terminal of the operational amplifier U1 is connected to the power through the second resistor R2. An output of the factor compensation module 400;

When the signal of the non-inverting input terminal of the operational amplifier U1 is equal to the signal of the inverting input terminal, the drive control module 200 outputs a driving signal to turn off the main switch S1.

A new control signal Vr' is obtained at the non-inverting input of U1, which is equal to the superposition of the original control signal Vr and the output signal Vxi of the power factor compensation module 400. The original control signal Vr does not change with the change of the input voltage Vdc, and the output signal Vxi of the power factor compensation module 400 is a sample value of the input voltage Vdc. When the two are superimposed, the new control signal Vr' input to the U1 positive phase input terminal is compared. The original control signal Vr is large (Vr is a broken line in FIG. 11 and Vr' is a solid line), and its increase amount Vr is the largest near the peak value of the input voltage Vdc, and is the smallest near the Vdc zero-crossing.

The input current lin is the average value of the current of the main switch S1. The input current also changes due to the change of the current peak control signal Vr, that is, the input current is increased from lin to lin ' (in Figure 11, lin is the dotted line, lin ' is a solid line', and lin is the largest near the peak of the input voltage Vdc, and lin is the smallest near the zero crossing of Vdc. See Fig. 11, which is the corresponding waveform diagram of Fig. 10.

Referring to FIG. 12, the figure is a schematic diagram of a seventh embodiment of a power factor compensation circuit suitable for peak current control according to the present invention.

The embodiment is based on the embodiment shown in FIG. 10, and the internal structure of the power factor compensation module 400 is embodied, including: a fifth resistor R5 and a sixth resistor R6;

The fifth resistor R5 and the sixth resistor R6 are connected in series, and are connected in parallel with the input voltage Vdc; the common ends of the fifth resistor R5 and the sixth resistor R6 are used as the power factor compensation module 400. Output.

It should be noted that the main circuit in the above embodiment may be an isolated circuit or a non-isolated circuit.

Hereinafter, a description will be given by taking an example in which the main circuit is a non-isolated Buck circuit.

Referring to Figure 13, the figure is a schematic diagram of an eighth embodiment of a power factor compensation circuit suitable for peak current control according to the present invention.

The buck circuit provided in this embodiment includes: a freewheeling diode D4, an inductor L and the main switch S1;

One end of the main switch S1 is connected to the anode of the freewheeling diode D4, the cathode of the freewheeling diode D4 is connected to the positive end of the input voltage Vdc and the positive end of the output voltage Vo, and the other end of the main switch S1 passes the first sampling resistor Rsl Grounding

The anode of the freewheeling diode D4 is connected to the negative terminal of the output voltage Vo through the inductor L. When the current control mode of the main circuit is the peak current control and the critical control mode (the waveform of the input current lin is the current waveform shown in FIG. 2), the present invention provides a power factor compensation circuit suitable for peak current control in the control mode. Underneath, the power factor improvement of the circuit is more obvious.

The peak current control refers to: a turn-off timing of the main switch S1, which is a time when the peak value of the current sampling signal in the main switch S1 is equal to the control signal Vr.

The critical control mode is: The conduction time of the main switch S1 is the time when the current of the freewheeling diode D4 or the inductor L is zero.

In the peak current control mode, the on-time Ton of the main switch S1 is the smallest near the peak of the input voltage Vdc, and the maximum near the Vdc zero-crossing;

Under the critical mode control, since the falling speed of the inductor current is only related to the output voltage Vo, the off time Toff of the main switch S1 (which is also the conduction time of the freewheeling diode D4) is constant when the output voltage Vo is constant. Unchanged

Duty cycle of main switch S1 D=Ton/(Ton+Toff)=l-Toff/(Ton+Toff) , input current

Iin=D*Ism/2, (where Ism is the current peak of the main switch S1, Ism*Rs=Vs). Since the current peak Ism of the main switch S1 does not change, the main switch is near the peak of the input voltage Vdc. The current slope of the tube is the largest, its corresponding Ton is the smallest, and the duty ratio D is the smallest. Therefore, the input current lin is the smallest.

When the input voltage Vdc is greater than the output voltage Vo, when the Buck circuit starts operating near zero crossing, The duty cycle D of the main switching transistor SI is the largest, and the input current Iin is the largest.

Preferably, the control signal Vr in the above embodiment may be a predetermined one of the reference voltage signals or a voltage signal associated with the output signal.

It should be noted that the operational amplifier U1 in the current control module 100 in the above embodiment may be a common integrated operational amplifier or a comparator.

It should be noted that the ultimate purpose of the peak current control in the above embodiment is to control the output current Io of the main circuit.

The above description is only a preferred embodiment of the invention and is not intended to limit the invention in any way. Although the present invention has been disclosed above in the preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention by using the methods and technical contents disclosed above, or modify the equivalents of equivalent changes without departing from the scope of the technical solutions of the present invention. Example. Therefore, any modifications, equivalent changes, and modifications made to the above embodiments in accordance with the technical spirit of the present invention are still within the scope of the technical solutions of the present invention.

Claims

Rights request

1. A power factor compensation circuit suitable for peak current control. The main circuit input current Iin in the power factor compensation circuit of the peak current control has a minimum peak value of the input voltage Vdc and is maximum before and after the input voltage Vdc crosses zero. The method includes: a drive control module, a current control module, and a power factor compensation module;

2. The power factor compensation circuit for peak current control according to claim 1, wherein when the power factor compensation module is configured to sample a driving signal of the switching tube in the main circuit or to sample a current signal of the main switching tube The compensation signal is compensated to the current control module, specifically:

3. The power factor compensation circuit for peak current control according to claim 2, wherein when the power factor compensation module samples the driving signal of the main switch, the power factor compensation module comprises: a resistor and a first capacitor;

4. The power factor compensation circuit for peak current control according to claim 1, wherein when the power factor compensation module is configured to sample a driving signal of the switching tube in the main circuit or to sample a current signal of the main switching tube The compensation signal is compensated to the current control module, specifically: The power factor compensation module filters and isolates the sampled signal and inputs it into the current control module.

The power factor compensation circuit for peak current control according to claim 4, wherein when the power factor compensation module samples the driving signal of the main switch, the power factor compensation module includes: a resistor, a first capacitor, and a second capacitor;

The power factor compensation circuit for peak current control according to claim 3 or 5, wherein the current control module comprises: a first sampling resistor, a third resistor, a seventh resistor, and an operational amplifier;

7. The power factor compensation circuit for peak current control according to claim 1, wherein when the power factor compensation module samples the input voltage Vdc, the sampling signal is compensated into the current control module, specifically Refers to:

The power factor compensation module directly inputs the sampling signal into the current control module.

8. The power factor compensation circuit for peak current control according to claim 7, wherein the power factor compensation module comprises: a fifth resistor and a sixth resistor;

The common ends of the fifth resistor and the sixth resistor serve as outputs of the power factor compensation module.

9. The power factor compensation circuit for peak current control according to claim 8, The current control module includes: a first sampling resistor, a second resistor, a fourth resistor, and an operational amplifier when the power factor compensation module samples the input voltage Vdc;

The power factor compensation circuit for peak current control according to claim 1, wherein when the power factor compensation module samples the current signal of the main switch tube, the method further includes: connecting the main switch tube in series a second sampling resistor, the two input ends of the power factor compensation module are respectively connected to two ends of the second sampling resistor to sample the current signal of the main switching tube;

The non-inverting input terminal of the operational amplifier is connected to the control signal; the inverting input terminal of the operational amplifier is connected to one end of the first sampling resistor through a seventh resistor, and the other end of the first sampling resistor is grounded; The input end is connected to the output end of the power factor compensation module through a third resistor;

A power factor compensation circuit suitable for peak current control according to claim 1, wherein said main circuit is an isolated circuit or a non-isolated circuit.

12. The power factor compensation circuit for peak current control according to claim 11, wherein the main circuit is a Buck circuit, comprising: a freewheeling diode, an inductor, and the main opening Guan Guan;

One end of the main switch tube is connected to the anode of the freewheeling diode, the cathode of the freewheeling diode is connected to the positive end of the input voltage Vdc and the positive end of the output voltage, and the other end of the main switch tube is grounded through the first sampling resistor;