TWI709839B - Correction control module of power factor correction circuit - Google Patents

Abstract

A correction control module of a power factor correction circuit includes a current sampling unit, an adjustment unit and a control unit. The current sampling unit generates a sampling current based on the work of a power factor correction circuit. The adjustment unit is connected to the current sampling unit and receives the sampling current. The adjustment unit consists of a fixed resistance branch and a parallel connection with the fixed resistance branch The variable resistance branch is composed of the variable resistance branch and the fixed resistance branch receives the current to generate a node voltage. The control unit controls the resistance of the variable resistance branch based on an input voltage and an output voltage of the power factor correction circuit, so that an equivalent resistance of the variable resistance branch and the fixed resistance branch is The value changes according to the working state of the power-cause correction circuit, so that the node voltage is not affected by the input voltage.

Description

Correction control module of power factor correction circuit

The invention relates to a correction control module of a power factor correction circuit.

Nowadays, the control of the power factor correction circuit is mainly performed by a correction control module, as disclosed in patent cases such as TW I459696, TW I466428, TW I590574, and CN1753290. The correction control module is mainly based on the power factor correction circuit The input voltage, output voltage, and working current are used as the basis for power factor adjustment. However, since the input voltage of the power factor correction circuit used in today's power supplies is as high as 380V, the working current of the power factor correction circuit is relatively small. Correcting the circuit mode of the control module will cause the working current to become smaller and cannot be adjusted appropriately, so that the control of the power factor and the current harmonic distortion cannot be effectively improved.

The main purpose of the present invention is to solve the problem that the conventional correction control module cannot adjust the circuit parameters according to the current so that the power factor and current harmonic distortion cannot be effectively improved.

To achieve the above objective, the present invention provides a correction control module for a power factor correction circuit, which includes a current sampling unit, an adjustment unit, and a control unit. The current sampling unit generates a sampling current based on the work of a power factor correction circuit. The adjustment unit is connected to the current sampling unit and receives the sampling current. The adjustment unit is composed of a fixed resistance branch and a parallel fixed resistance branch. The variable resistance branch includes a first field effect transistor, and the variable resistance branch and the fixed resistance branch receive the sampling current to generate a node voltage. The control unit is connected to the power factor correction circuit and the adjustment unit to obtain the node voltage, an input voltage and an output voltage, the control unit generates a control signal based on the input voltage and the output voltage, and the control signal is output to the first A gate of a field-effect transistor makes the field-effect transistor work in a linear mode to change an equivalent resistance value of the variable resistance branch and the fixed resistance branch, so that the node voltage is not affected by The level of the input voltage affects.

In one embodiment, the control unit has a node voltage input terminal and a reference potential connection terminal, one of the parallel nodes of the variable resistance branch and the fixed resistance branch is connected to the node voltage input terminal, and the other is connected in parallel The node is connected to the reference potential connection terminal.

In one embodiment, the variable resistance branch includes a first resistor connected in series with the first field effect transistor, and the fixed resistance branch includes at least one second resistor.

In one embodiment, the power factor correction circuit includes an input capacitor, and the current sampling unit includes at least one third resistor connected to the negative electrode of the input capacitor and an operational amplifier. The operational amplifier has a third resistor connected to the third resistor but not connected to the A positive input terminal at one end of the input capacitor, a negative input terminal connected to the third resistor and the negative electrode of the input capacitor, and an output terminal connected to the adjustment unit.

In one embodiment, the power factor correction circuit includes a second field-effect transistor, the current sampling unit includes a first current comparator and a first diode, and the first current comparator has a circuit connected in series with the second current sampling unit. The first winding of the drain of the field effect transistor and a second winding that is magnetically coupled with the first winding and connected to the first diode.

In one embodiment, the power factor correction circuit includes an output capacitor, a second diode connected to the output capacitor, the negative electrode of the second diode is connected to the positive electrode of the output capacitor, and the current sampling unit includes a second diode. A comparator and a third diode, the second comparator having a third winding connected in series with the positive pole of the second diode and a third winding magnetically coupled to the third winding and connected to the third diode The fourth winding.

According to the foregoing disclosure, compared with the conventional technology, the present invention has the following characteristics: the first field effect transistor of the present invention changes the resistance according to the control of the control signal, so that the resistance of the variable resistance branch is changed , So that the equivalent resistance values of the variable resistance branch and the fixed resistance branch are changed. Thereby, the correction control module can prevent the current harmonic distortion from being generated when the sampling current becomes small even when the power factor correction circuit is high-voltage input. Optimized due to calibration.

The detailed description and technical content of the present invention are described as follows with the drawings:

Please refer to FIG. 1, the present invention provides a calibration control module 100, the calibration control module 100 controls the operation of the power factor correction circuit 200 based on feedback information from the power factor correction circuit 200. Wherein, the power factor correction circuit 200 can be configured in a power supply module and has been notified by those skilled in the art, and will not be repeated here. Furthermore, the calibration control module 100 includes a current sampling unit 11, an adjustment unit 13 and a control unit 14. The current sampling unit 11 is connected to the power factor correction circuit 200 and generates a sampling current 110 based on the work of the power factor correction circuit 200. The adjustment unit 13 is connected to the current sampling unit 11 and receives the sampling current 110. Further, the The adjusting unit 13 is composed of a fixed resistance branch 131 and a variable resistance branch 132 connected in parallel with the fixed resistance branch 131. The variable resistance branch 132 includes a first field effect transistor 133 . Furthermore, the variable resistance branch 132 and the fixed resistance branch 131 generate an equivalent resistance. After the variable resistance branch 132 and the fixed resistance branch 131 receive the sampling current 110, they will One of the parallel nodes generates a node voltage 134.

On the other hand, the control unit 14 may be realized by an integrated circuit (IC), and the control unit 14 is connected to the power factor correction circuit 200 and the adjustment unit 13 to obtain the node voltage 134, an input voltage 21, and One output voltage 22. Wherein, the control unit 14 is directly connected to an input point and an output point of the power factor correction circuit 200 to obtain the input voltage 21 and the output voltage 22. Furthermore, the control unit 14 uses the node voltage 134 as a control reference, and provides a pulse width modulation signal 142 to a second field effect transistor 23 of the power factor correction circuit 200 via a control signal output terminal 141 (I.e. PWM signal) for active adjustment of power factor. In addition, the control unit 14 of the present invention generates a control signal 143 based on the input voltage 21 and the output voltage 22. Although the control signal 143 is a signal generated based on pulse width modulation technology, the control The control object of the signal 143 and the pulse width modulation signal 142 is different. The former controls the first field effect transistor 133 and the latter controls the second field effect transistor 23.

In addition, the control signal 143 is output to a gate 135 of the first field effect transistor 133, and the first field effect transistor 133 will work in a linear mode (or ohmic mode) after being controlled by the control signal 143 , The first field-effect transistor 133 changes the resistance according to the control signal 143 to change the resistance of the variable resistance branch 132, so that the variable resistance branch 132 and the fixed resistance branch The equivalent resistance of 131 changes. In this way, when the power factor correction circuit 200 is high-voltage input, the calibration control module 100 does not affect the node voltage even if the sampling current 110 becomes smaller, so as to avoid the generation of current harmonic distortion and make the power The power factor correction of the correction circuit 200 is optimized.

Please refer to FIGS. 1 and 2. In one embodiment, the control unit 14 has a node voltage input terminal 144 and a reference potential connection terminal 145. Among the variable resistance branch 132 and the fixed resistance branch 131 A parallel node is connected to the node voltage input terminal 144, and the other parallel node is connected to the reference potential connection terminal 145. In addition, in one embodiment, the variable resistance branch 132 includes a first resistor 136 connected in series with the first field effect transistor 133, and the fixed resistance branch 131 includes at least one second resistor 137 Both the first resistor 136 and the second resistor 137 are elements with a fixed resistance.

Please refer to FIG. 2 again to illustrate the implementation structure of an embodiment of the current sampling unit 11. The power factor correction circuit 200 includes an input capacitor 24, and the current sampling unit 11 includes at least one third resistor 111 connected to the negative electrode of the input capacitor 24 and an operational amplifier 112. The operational amplifier 112 has a third resistor 111 connected to it. A positive input terminal 113 not connected to one end of the input capacitor 24, a negative input terminal 114 connected to the third resistor 111 and the negative electrode of the input capacitor 24, and an output terminal 115 connected to the adjustment unit 13. In conclusion, the working principle of the operational amplifier 112 has been notified by those skilled in the art, and will not be repeated here. In addition, the current sampling unit 11 of the present invention is not limited to the foregoing. Please refer to FIG. 3. In another embodiment, the current sampling unit 11 includes a first current comparator 116 and a first diode 117. The first current converter 116 has a first winding 118 connected in series with the drain of the second field effect transistor 23, and a first winding 118 coupled to the first winding 118 and connected to the first diode 117. Two winding 119. 4, in one embodiment, the power factor correction circuit 200 includes an output capacitor 25, a second diode 26 connected to the output capacitor 25, and the negative electrode of the second diode 26 is connected to the output capacitor 25, the current sampling unit 11 includes a second current comparator 120 and a third diode 121, the second current comparator 120 has a third winding connected in series with the anode of the second diode 26 122 and a fourth winding 123 magnetically coupled to the third winding 122 and connected to the third diode 121. Furthermore, the circuits disclosed in FIGS. 3 and 4 of the present invention can be implemented together, as disclosed in FIG. 5, so that the control unit 14 can omit the program calculation mechanism.

Please refer to FIG. 6. The aforementioned input voltage 21 is an example of the input of the power factor correction circuit 200. In one embodiment, the input voltage 21 may refer to the voltage at which the power supply module receives the mains power into the subsequent circuit. The capture points can refer to a first voltage capture point 27 and a second voltage capture point 28 depicted in FIG. 6, and the control unit 14 has the first voltage capture point 27 and the second voltage capture point respectively connected to each other. Capture the two input terminals 146 and 147 of the point 28.

In summary, it is only a preferred embodiment of the present invention. When the scope of implementation of the present invention cannot be limited by this, that is, all equal changes and modifications made according to the scope of the patent application of the present invention shall still belong to the present invention. The scope of patent coverage.

100: Calibration control module 11: Current sampling unit 110: sampling current 111: third resistor 112: Operational amplifier 113: Positive input 114: negative input 115: output 116: first ratio flowr 117: The first diode 118: first winding 119: second winding 120: second ratio flowr 121: The third diode 122: third winding 123: Fourth winding 13: adjustment unit 131: Resistance fixed branch 132: variable resistance branch 133: The first field effect transistor 134: Node voltage 135: Gate 136: first resistance 137: second resistor 14: Control unit 141: Control signal output terminal 142: Pulse width modulation signal 143: Control signal 144: Node voltage input 145: Reference potential connection terminal 146, 147: Input 200: Power factor correction circuit 21: Input voltage 22: output voltage 23: The second field effect transistor 24: Input capacitance 25: output capacitor 26: The second diode 27: The first voltage capture point 28: Second voltage capture point

Fig. 1 is a schematic diagram of the composition of an embodiment of the present invention. Fig. 2 is a schematic circuit diagram of an embodiment of the present invention. Fig. 3 is a schematic circuit diagram (1) of another embodiment of the present invention. Fig. 4 is a schematic circuit diagram (2) of another embodiment of the present invention. Fig. 5 is a schematic circuit diagram (3) of another embodiment of the present invention. Fig. 6 is a schematic circuit diagram (4) of another embodiment of the present invention.

100: Calibration control module

11: Current sampling unit

110: sampling current

13: adjustment unit

131: Resistance fixed branch

132: variable resistance branch

133: The first field effect transistor

134: Node voltage

135: Gate

136: first resistance

137: second resistor

14: Control unit

142: Pulse width modulation signal

143: Control signal

144: Node voltage input

145: Reference potential connection terminal

200: Power factor correction circuit

21: Input voltage

22: output voltage

Claims (11)

A correction control module of a power factor correction circuit, including: A current sampling unit generates a sampling current based on the work of a power factor correction circuit; An adjustment unit connected to the current sampling unit and receiving the sampled current. The adjustment unit is composed of a fixed resistance branch and a variable resistance branch connected in parallel with the fixed resistance branch. The resistance is variable The branch includes a first field effect transistor, the variable resistance branch and the fixed resistance branch receive the sampling current to generate a node voltage; and A control unit connected to the power factor correction circuit and the adjustment unit to obtain the node voltage, an input voltage and an output voltage, the control unit generates a control signal based on the input voltage and the output voltage, and the control signal is output to the A gate of the first field-effect transistor makes the field-effect transistor work in a linear mode to change an equivalent resistance value of the variable resistance branch and the fixed resistance branch, so that the node voltage is not Affected by the input voltage. The correction control module of the power factor correction circuit according to claim 1, wherein the control unit has a node voltage input terminal and a reference potential connection terminal, and one of the variable resistance branch and the fixed resistance branch A parallel node is connected to the node voltage input terminal, and the other parallel node is connected to the reference potential connection terminal. The correction control module of the power factor correction circuit according to claim 1 or 2, wherein the variable resistance branch includes a first resistor connected in series with the first field effect transistor, and the fixed resistance branch includes At least one second resistor. The correction control module of the power factor correction circuit according to claim 3, wherein the power factor correction circuit includes an input capacitor, and the current sampling unit includes at least one third resistor connected to the negative electrode of the input capacitor and an operational amplifier, The operational amplifier has a positive input terminal connected to the third resistor but not connected to the input capacitor, a negative input terminal connected to the third resistor and the negative electrode of the input capacitor, and an output terminal connected to the adjustment unit. The correction control module of the power factor correction circuit according to claim 3, wherein the power factor correction circuit includes a second field effect transistor, and the current sampling unit includes a first current converter and a first diode The first current converter has a first winding connected in series with the drain of the second field effect transistor and a second winding magnetically coupled with the first winding and connected to the first diode. The correction control module of the power factor correction circuit according to claim 5, wherein the power factor correction circuit includes an output capacitor, a second diode connected to the output capacitor, and the negative pole of the second diode is connected to the The positive pole of the output capacitor. The current sampling unit includes a second current comparator and a third diode. The second current comparator has a third winding connected in series with the positive pole of the second diode and a third winding connected to the second diode. The three windings are magnetically coupled and connected to the fourth winding of the third diode. The correction control module of the power factor correction circuit according to claim 3, wherein the power factor correction circuit includes an output capacitor, a second diode connected to the output capacitor, and the negative electrode of the second diode is connected to the The positive pole of the output capacitor. The current sampling unit includes a second current comparator and a third diode. The second current comparator has a third winding connected in series with the positive pole of the second diode and a third winding connected to the second diode. The three windings are magnetically coupled and connected to the fourth winding of the third diode. The correction control module of the power factor correction circuit according to claim 1 or 2, wherein the power factor correction circuit includes an input capacitor, and the current sampling unit includes at least one third resistor connected to the negative electrode of the input capacitor and an operation The operational amplifier has a positive input terminal connected to the third resistor but not connected to the input capacitor, a negative input terminal connected to the third resistor and the negative electrode of the input capacitor, and an output terminal connected to the adjustment unit. The correction control module of the power factor correction circuit according to claim 1 or 2, wherein the power factor correction circuit includes a second field effect transistor, and the current sampling unit includes a first current converter and a first two A pole body. The first current converter has a first winding connected in series to the drain of the second field effect transistor and a second winding magnetically coupled to the first winding and connected to the first diode. The correction control module of the power factor correction circuit according to claim 9, wherein the power factor correction circuit includes an output capacitor, a second diode connected to the output capacitor, and the negative electrode of the second diode is connected to the The positive pole of the output capacitor. The current sampling unit includes a second current comparator and a third diode. The second current comparator has a third winding connected in series with the positive pole of the second diode and a third winding connected to the second diode. The three windings are magnetically coupled and connected to the fourth winding of the third diode. The correction control module of the power factor correction circuit according to claim 10, wherein the power factor correction circuit includes an output capacitor, a second diode connected to the output capacitor, and the negative electrode of the second diode is connected to the The positive pole of the output capacitor. The current sampling unit includes a second current comparator and a third diode. The second current comparator has a third winding connected in series with the positive pole of the second diode and a third winding connected to the second diode. The three windings are magnetically coupled and connected to the fourth winding of the third diode.

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