High-power PFC circuit

Abstract

The utility model relates to the technical field of electric tools, and discloses a high-power PFC circuit with strong impact resistance and high stability, which comprises a control module (130) used for outputting pulse signals, the control module (130) comprises a current detection circuit (131), the current detection circuit (131) comprises a twenty-fourth resistor (R24), an eleventh diode (D11) and a twelfth capacitor (C12), and the twenty-fourth resistor (R24), the eleventh diode (D11) and the twelfth capacitor (C12) are connected with the twenty-fourth resistor (R24). A twenty-fourth resistor (R24) is connected with an eleventh diode (D11) in series and then is connected with a twelfth capacitor (C12) in parallel, and a cathode (D11) of the eleventh diode is connected with one end of the twelfth capacitor (C12).

Description

Technical Field

[0001] The utility model relates to the technical field of electric tools, and more specifically to a high-power PFC circuit. Background Art

[0002] Currently, many designers use DCM PFC (Power Factor Correction) circuits, which have a low output power and can only meet the requirements of low-power electrical equipment. However, the existing high-power PFC circuits always explode when turned on (or started), and the repeated impact performance is poor, making the impact risk performance of electrical equipment poor. When overshoot / overpower occurs, it will cause the problem of explosion, resulting in poor product stability.

[0003] Therefore, how to improve the performance of repeated impact and product stability has become a technical problem that technical personnel in this field need to solve urgently. Utility Model Content

[0004] The technical problem to be solved by the present invention is that, in view of the poor stability of the above-mentioned repeated impact performance of the prior art, which makes the impact risk performance of the electrical equipment poor, and when overshoot / overpower occurs, it will cause the defect of machine explosion, a high-power PFC circuit with strong impact resistance and high stability is provided.

[0005] The technical solution adopted by the utility model to solve the technical problem is: construct a high-power PFC circuit, including a control module for outputting a pulse signal, wherein:

[0006] The control module includes a current detection circuit,

[0007] The input end of the current detection circuit is connected to an output end of the boost module for receiving a current signal, wherein:

[0008] The current detection circuit includes a twenty-fourth resistor, an eleventh diode and a twelfth capacitor,

[0009] The twenty-fourth resistor is connected in series with the eleventh diode and then connected in parallel with the twelfth capacitor.

[0010] One end of the twenty-fourth resistor is connected to an output end of the boost module,

[0011] A cathode of the eleventh diode is connected to one end of the twelfth capacitor.

[0012] In some embodiments, the control module further includes a main controller.

[0013] The current feedback terminal of the main controller is connected to the anode of the eleventh diode and one end of the twelfth capacitor.

[0014] In some embodiments, the control module further includes a voltage detection circuit.

[0015] One end of the voltage detection circuit is connected to an output end of the boost module for receiving a voltage signal.

[0016] The other end of the voltage detection circuit is connected to the voltage feedback end of the main controller.

[0017] In some embodiments, the boost module includes a clamping circuit and a detection resistor RS1 connected in parallel.

[0018] One end of the clamping circuit is connected to one end of the detection resistor,

[0019] The other end of the clamping circuit is connected to the other end of the detection resistor.

[0020] In some embodiments, the boost module further includes a first MOS tube.

[0021] The gate of the first MOS tube is connected to a signal output terminal of the main controller.

[0022] The drain of the first MOS tube is connected to the output end of the EMC module.

[0023] The source of the first MOS tube is connected to one end of the detection resistor.

[0024] In some embodiments, the boost module further includes a first inductor and a second inductor connected in series.

[0025] One end of the first inductor is connected to the output end of the EMC module,

[0026] One end of the second inductor is connected to the drain of the first MOS tube.

[0027] In some embodiments, the boost module further includes a thermistor.

[0028] One end of the thermistor is connected to one end of the second inductor,

[0029] The other end of the thermistor is connected to the circuit output end.

[0030] In some embodiments, a switch module is further included.

[0031] One end of the switch module is connected to the output end of the control module,

[0032] The other end of the switch module is coupled to the output end of the boost module.

[0033] In some embodiments, the switch module includes a first transistor and a relay.

[0034] The base of the first transistor and one end of the coil of the relay are respectively connected to the output end of the control module.

[0035] The collector of the first transistor is connected to the other end of the coil of the relay.

[0036] One end of the normally open switch of the relay is connected to one end of the thermistor,

[0037] The other end of the normally open switch of the relay is connected to the other end of the thermistor.

[0038] The high-power PFC circuit described in the utility model includes a control module for outputting a pulse signal, wherein the control module includes a current detection circuit, the current detection circuit includes a twenty-fourth resistor, an eleventh diode and a twelfth capacitor, the twenty-fourth resistor is connected in series with the eleventh diode and then connected in parallel with the twelfth capacitor, and the cathode of the eleventh diode is connected to one end of the twelfth capacitor. Compared with the prior art, by adding a diode reverse protection to the current detection circuit, the performance of repeated impact is improved, which can effectively solve the problem that the repeated impact performance of the PFC circuit is poorly stable, resulting in poor impact risk performance of the electrical equipment, and when overshoot / overpower occurs, it will cause the problem of explosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0040] Figure 1 The utility model provides a circuit principle diagram of an embodiment of a high-power PFC circuit. DETAILED DESCRIPTION

[0041] In order to have a clearer understanding of the technical features, purposes and effects of the present utility model, the specific implementation methods of the present utility model are now described in detail with reference to the accompanying drawings.

[0042] like Figure 1 As shown, in the first embodiment of the high-power PFC circuit of the present invention, the high-power PFC circuit 100 includes an EMC module 110 , a boost module 120 , a control module 130 and a switch module 140 .

[0043] The EMC module 110 is used to receive the voltage signal input from the mains side, rectify the full-wave sine wave into a half-wave signal through the rectifier bridge BD1 rectifier circuit, and then output it to the subsequent circuit;

[0044] The boost module 120 is used to boost the half-wave signal input by the EMC module 110 and output a stable 380V voltage;

[0045] The control module 130 has the functions of current / current sampling, signal comparison, and adjusting the duty cycle of the control signal;

[0046] The switch module 140 is used to switch the output of the PFC circuit, that is, the switch module 140 works only when the PFC circuit is stable;

[0047] The control module 130 is used to output at least one pulse signal (high level or low level), wherein:

[0048] The control module 130 includes a current detection circuit 131, which is used to detect the current signal flowing through the main circuit of the boost module 120 and output the current signal to the main controller U1 of the control module 130, which is set with a preset value;

[0049] Specifically, the input end of the current detection circuit 131 is connected to an output end of the boost module 120 to obtain a current signal flowing through the main circuit of the boost module 120, wherein:

[0050] The current detection circuit 131 includes a twenty-fourth resistor R24, an eleventh diode D11, and a twelfth capacitor C12, wherein the twenty-fourth resistor R24 ​​is a sampling resistor, and the eleventh diode D11 is used for reverse impact protection.

[0051] Specifically, the twenty-fourth resistor R24 ​​is connected in series with the eleventh diode D11 and then connected in parallel with the twelfth capacitor C12.

[0052] One end of the twenty-fourth resistor R24 ​​is connected to an output end of the boost module 120.

[0053] One end of the twenty-fourth resistor R24 ​​is also connected to the anode of the eleventh diode D11.

[0054] The cathode of the eleventh diode D11 is connected to one end of the twelfth capacitor C12.

[0055] An anode of the eleventh diode D11 and the other end of the twelfth capacitor C12 are connected to a common end.

[0056] By using the present technical solution, by adding a diode reverse protection to the current detection circuit 131, the performance of repeated impact is improved, which can effectively solve the problem that the repeated impact performance of the PFC circuit is poorly stable, resulting in poor impact risk performance of the electrical equipment, and when overshoot / overpower occurs, it will cause the problem of machine explosion.

[0057] In some embodiments, in order to improve the reliability of the PFC circuit operation, a main controller U1 may be provided in the control module 130, which has signal comparison and output pulse signals;

[0058] Specifically, the current feedback end of the main controller U1 (corresponding to pin 3) is connected to the anode of the eleventh diode D11 and one end of the twelfth capacitor C12. The current signal is input into the main controller U1 after being divided by the twenty-fourth resistor R24 ​​and filtered by the twelfth capacitor C12. The main controller U1 compares the input current signal with the preset value and adjusts the duty cycle of the output pulse signal according to the comparison result of the two, thereby adjusting the boost state of the boost module 120.

[0059] In some embodiments, in order to ensure the stability of the output voltage, a voltage detection circuit 132 may be provided in the control module 130, which is used to obtain a voltage signal of an output terminal (corresponding to the HV terminal) of the boost module 120;

[0060] Specifically, one end of the voltage detection circuit 132 is connected to an output end (corresponding to the HV end) of the boost module 120 to receive a voltage signal.

[0061] The other end of the voltage detection circuit 132 is connected to the voltage feedback end of the main controller U1, and the acquired voltage signal is input into the main controller U1. The main controller U1 compares the input voltage signal with the preset value, and adjusts the duty cycle of the output pulse signal according to the comparison result, thereby adjusting the boost value of the boost module 120.

[0062] In some embodiments, in order to improve the safety of the PFC circuit operation, a clamping circuit 121 and a detection resistor RS1 may be provided in the boost module 120, wherein the clamping circuit 121 is connected in parallel with the detection resistor RS1.

[0063] One end of the clamping circuit 121 is connected to one end of the detection resistor RS1.

[0064] The other end of the clamp circuit 121 is connected to the other end of the detection resistor RS1 .

[0065] Specifically, the clamping circuit 121 includes a third diode D32 and a fourth diode D32A connected in series, wherein the cathode of the third diode D32 is connected to one end of the detection resistor RS1.

[0066] An anode of the fourth diode D32A is connected to the other end of the detection resistor RS1 .

[0067] Specifically, since the internal capacitive reactance of capacitor EC1 is short-circuited to 0Ω at the moment of charging, the charging current is discharged from the positive electrode of capacitor EC1 to the ground, and the current returns to the negative electrode of rectifier bridge BD1 through the detection resistor RS1. At this time, the current flowing through the detection resistor RS1 is particularly large. When the voltage across the detection resistor RS1 exceeds -4V, RS1 will be at risk of open circuit. Therefore, two diodes are connected in parallel at both ends of the detection resistor RS1 to clamp it at about 1.4V.

[0068] When the voltage approaches -4V, it is clamped to 1.4V by the third diode D32 and the fourth diode D32A, which can effectively protect the detection resistor RS1 from being damaged by the impact.

[0069] In some implementations, in order to improve the PFC boost effect, a first MOS transistor Q1 may be provided in the boost module 120, which is selected as an N-channel MOS transistor and has a switch function;

[0070] The gate of the first MOS tube Q1 is connected to a signal output terminal (corresponding to pin 3) of the main controller U1 through the sixteenth resistor R16, and the pulse signal output by the main controller U1 is input to the gate of the first MOS tube Q1 through the sixteenth resistor R16.

[0071] The drain of the first MOS transistor Q1 is connected to the output end of the EMC module 110, that is, the drain of the first MOS transistor Q1 is connected to the positive electrode of the rectifier bridge BD1, and is used to receive the full-wave current signal rectified by the rectifier bridge BD1.

[0072] The source of the first MOS transistor Q1 is connected to one end of the detection resistor RS1 and the anode of the fourth diode D32A respectively.

[0073] When the input pulse signal is at a high level, the first MOS tube Q1 is turned on.

[0074] When the input pulse signal is at a low level, the first MOS tube Q1 is controlled to be cut off.

[0075] In some embodiments, the boost module 120 further includes a first inductor L101 and a second inductor L102 connected in series, which have the function of storing energy;

[0076] Specifically, one end of the first inductor L101 is connected to the output end of the EMC module 110, specifically, one end of the first inductor L101 is connected to the positive electrode of the rectifier bridge BD1, for receiving the full-wave current signal rectified by the rectifier bridge BD1.

[0077] One end of the second inductor L102 is connected to the drain of the first MOS transistor Q1 .

[0078] When the first MOS tube Q1 is controlled to be turned on, the current signal passes through the first inductor L101, the second inductor L102 and the first MOS tube Q1 to charge and store energy in the first inductor L101 and the second inductor L102.

[0079] When the first MOS tube Q1 is controlled to be turned off, the input current signal and the current signals released by the first inductor L101 and the second inductor L102 are superimposed to form a boost state, and then the capacitor EC1 and the third capacitor C3 are charged to increase the output voltage value of the PFC circuit;

[0080] The duty cycle of the output pulse signal is adjusted by the main controller U1, thereby controlling the on / off frequency of the first MOS tube Q1 to achieve a boosting effect.

[0081] In some embodiments, the boost module 120 further includes a thermistor TH1, which is used for current limiting.

[0082] One end of the thermistor TH1 is connected to one end of the second inductor L102.

[0083] One end of the thermistor TH1 is connected to the output end of the boost module 120 (corresponding to the HV end).

[0084] The output voltage signal is added to the output end (corresponding to the HV end) of the boost module 120 via the second inductor L102 and the thermistor TH1 , and the startup current is limited by the thermistor TH1 .

[0085] In some implementations, in order to improve the reliability of the PFC circuit, a switch module 140 may be provided in the PFC circuit, wherein one end of the switch module 140 is connected to the output end of the control module 130 to receive a control signal output by the control module 130.

[0086] The other end of the switch module 140 is coupled to the output end of the boost module 120 .

[0087] Specifically, the switch module 140 includes a first transistor Q2 and a relay K1, wherein the first transistor Q2 is selected as an NPN transistor and has a switch function;

[0088] The base of the first transistor Q2 is connected to the output terminal (corresponding to the VCC-P terminal) of the main controller U1 (belonging to the control module 130) through the twenty-seventh resistor R27, and is used to receive the control signal.

[0089] One end of the coil of the relay K1 (corresponding to pin 1) is connected to the output end (corresponding to the VCC-P end) of the main controller U1 (belonging to the control module 130) through the twenty-second resistor R22, for receiving the control signal.

[0090] The collector of the first transistor Q2 is connected to the other end of the coil of the relay K1 (corresponding to pin 2).

[0091] One end of the normally open switch of relay K1 (corresponding to pin 3) is connected to one end of the thermistor TH1.

[0092] The other end of the normally open switch of relay K1 (corresponding to pin 4) is connected to the other end of the thermistor TH1.

[0093] When the input control signal is at a high level, the first transistor Q2 is controlled to be turned on, a current signal passes through the coil of the relay K1, the normally open switch of the relay K1 is closed, the thermistor TH1 is disconnected, and the large current signal passes through the normally open switch of the relay K1 to the output end (corresponding to HV).

[0094] Specifically, when the capacitor EC1 is fully charged, the voltage across the capacitor EC1 remains unchanged, supplying the auxiliary power supply, and the external power supply "VCC_P" voltage is used to power the 7th pin through the 18th resistor R18, so that the 8th pin of the main controller U1 outputs a driving signal through the 16th resistor R16, the third diode D3, the first resistor R1 and the fourth resistor R4, so that the first MOS tube Q1 switches and works, and combined with the second inductor L102 to store energy, the second diode D2 is boosted, the 60th capacitor C60, the 66th resistor R160, and the 58th resistor R158 play a filtering role, and pass through the thermistor TH1 to filter the capacitor EC1, and the DC voltage after rectification and filtering by the capacitor EC1 is sent to the 6th pin of the main controller U1 through the second resistor R2, the 10th resistor R10, the 17th resistor R17, the 34th resistor R34 and the 11th capacitor C11 for comparison, and then a stable 380V voltage is output;

[0095] The thirty-second resistor R32, the sixteenth capacitor C16 and the thirteenth capacitor C13 form a current compensation circuit 134.

[0096] The thirty-third resistor R33, the seventeenth capacitor C17 and the fifteenth capacitor C15 are the voltage compensation circuit 133, and the thirty-sixth resistor R36 and the fourteenth capacitor C14 are the frequency setting;

[0097] When the input current is too large, it is sent to the 3rd pin of the main controller U1 by the 24th resistor R24, the 11th diode D11 and the 12th capacitor C12, and sent to the inside for calculation, and the output current is adjusted by outputting a relatively stable working frequency, thereby achieving a stable voltage and current effect;

[0098] Since the startup current and load current of the power device are relatively large, the first MOS tube Q1 uses Infineon MOS tube, which has super load capacity and reduces the conduction loss and cross loss of the PFC main MOS tube; the second diode D2 uses a strong silicon carbide diode with no reverse recovery time, which reduces the reverse recovery loss of the diode, reduces the heat loss of the product, and improves the FPC efficiency;

[0099] Since the AC input voltage charges the capacitor EC1 at the moment of startup, the startup current is relatively large, so the thermistor TH1 is set to a 10Ω resistor. When the startup current passes through the thermistor TH1 resistor, the current is limited.

[0100] When the voltage across capacitor EC1 rises to a stable state, the voltage of the external power supply "VCC_P" drives the twenty-seventh resistor R27, the fifty-seventh capacitor C57, the thirtieth resistor R30 and the first transistor Q2 to turn on relay K1, and "VCC_P" passes through the twenty-second resistor R22, the fourteenth diode D14, relay K1, and the first transistor Q2_C-E pole to the ground. Relay K1D pins 3 and 4 are connected in parallel with the resistors across the thermistor TH1, reducing the voltage drop across the thermistor TH1, and reducing the loss across the thermistor TH1 when overloaded. Relay K1 does not operate when starting the machine at no load, and the starting current passes through the thermistor TH1 to reduce the impact current. When the PFC output is stable, relay K1 works and replaces the thermistor TH1 to work, thereby improving the product's excessive current requirements, reducing product losses, and improving product efficiency. Using this technical solution, the main power device uses a transistor with strong impact resistance and no reverse recovery, and at the same time increases the relay working circuit, reduces the product's impact risk, and improves the product performance requirements.

[0101] The embodiments of the utility model are described above in conjunction with the accompanying drawings, but the utility model is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the utility model, ordinary technicians in this field can also make many forms without departing from the scope of protection of the utility model and the claims, which all fall within the protection of the utility model.

Claims

1. A high-power PFC circuit, characterized in that: It includes a control module for outputting a pulse signal, wherein: The control module includes a current detection circuit, The input end of the current detection circuit is connected to an output end of the boost module for receiving a current signal, wherein: The current detection circuit includes a twenty-fourth resistor, an eleventh diode and a twelfth capacitor, The twenty-fourth resistor is connected in series with the eleventh diode and then connected in parallel with the twelfth capacitor. One end of the twenty-fourth resistor is connected to an output end of the boost module, A cathode of the eleventh diode is connected to one end of the twelfth capacitor.

2. The high-power PFC circuit according to claim 1, characterized in that: The control module also includes a main controller. The current feedback terminal of the main controller is connected to the anode of the eleventh diode and one end of the twelfth capacitor.

3. The high-power PFC circuit according to claim 2, characterized in that: The control module also includes a voltage detection circuit, One end of the voltage detection circuit is connected to an output end of the boost module for receiving a voltage signal. The other end of the voltage detection circuit is connected to the voltage feedback end of the main controller.

4. The high-power PFC circuit according to claim 3, characterized in that: The boost module includes a clamping circuit and a detection resistor connected in parallel, One end of the clamping circuit is connected to one end of the detection resistor, The other end of the clamping circuit is connected to the other end of the detection resistor.

5. The high-power PFC circuit according to claim 4, characterized in that: The boost module further includes a first MOS tube. The gate of the first MOS tube is connected to a signal output terminal of the main controller. The drain of the first MOS tube is connected to the output end of the EMC module. The source of the first MOS tube is connected to one end of the detection resistor.

6. The high-power PFC circuit according to claim 5, characterized in that: The boost module further includes a first inductor and a second inductor connected in series. One end of the first inductor is connected to the output end of the EMC module, One end of the second inductor is connected to the drain of the first MOS tube.

7. The high-power PFC circuit according to claim 6, characterized in that: The boost module also includes a thermistor, One end of the thermistor is connected to one end of the second inductor, The other end of the thermistor is connected to the circuit output end.

8. The high-power PFC circuit according to claim 7, characterized in that: Also includes a switch module, One end of the switch module is connected to the output end of the control module, The other end of the switch module is coupled to the output end of the boost module.

9. The high-power PFC circuit according to claim 8, characterized in that: The switch module includes a first transistor and a relay. The base of the first transistor and one end of the coil of the relay are respectively connected to the output end of the control module. The collector of the first transistor is connected to the other end of the coil of the relay. One end of the normally open switch of the relay is connected to one end of the thermistor, The other end of the normally open switch of the relay is connected to the other end of the thermistor.

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