Improved full-range active power factor correction circuit

Abstract

The utility model provides an improved full-range active power factor correction circuit, which relates to the field of power supply control and comprises a rectification filter module, a BOOST module, a detection switching module and a PFC modulation module. The rectification filtering module is connected with the BOOST module, the detection switching module and the PFC modulation module, and the PFC modulation module is connected with the BOOST module and the detection switching module. The circuit provided by the utility model realizes a full-range power factor correction function, also realizes a function of reducing harmonic components of an input end during light load, high power factor and heavy load, optimizes the active PFC circuit by adopting a simplified design circuit, can meet detection requirements and field application, and has good reliability and universality.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of power supply control especially relates to an improved full-range active power factor correction circuit. BACKGROUND

[0002] The long-term load of the battery charging type switching power supply of the power distribution automation remote terminal DTU / FTU in the prior art includes a core unit, a communication unit, a remote signaling unit and a remote control unit and the like, and the total power of these loads is 4-20W. When the battery charging type switching power supply of the DTU / FTU needs to output a transient large load to drive a switch for remote on-off control of a line during maintenance and fault of a distribution line, the instantaneous power of the on-off of the switch can reach 1KW or even higher. In order to reduce input current harmonics, improve AC sampling accuracy, and improve the utilization rate of power supply, the power supply used in conjunction will use an active PFC circuit to modulate the input current.

[0003] The power consumption of the DTU / FTU terminal is clearly specified in the power distribution automation terminal detection outline and the power distribution automation remote terminal DL / T721-2013 of the China Electric Power Research Institute, and it is required that the apparent power of the three-remote FTU is ≤30VA and the apparent power of the three-remote DTU is ≤40VA. The power factor of the battery charging type switching power supply of the DTU / FTU should be >0.8 when the electronic equipment load is 4-20W to meet the detection requirements, but the maximum output power of the power supply is 500-1000W, and if the power supply is power factor corrected in the entire power range, the power factor of the power supply cannot meet the requirement of >0.8 when the load is 4-20W.

[0004] The active PFC circuit used in the industry at present can only work at 5-50W, and stops working when the output load is greater than 50W. The power factor correction circuit of this scheme can meet the requirement of power factor >0.8 when the output load is 4-20W, but there is no PFC circuit to correct the input current in the full power range, and a large harmonic current is generated when a large load is output, which reduces the utilization rate of the power grid and seriously distorts the input voltage and current waveform sampled. CONTENT OF THE UTILITY MODEL

[0005] Therefore, the utility model aims at providing an improved full-range active power factor correction circuit to solve the technical problem that the modulated current sampled by the existing active PFC circuit is very small when the power supply works at a small load, which limits the improvement of the input end PF value of the power supply, and causes the apparent power of the power supply to the terminal to fail to meet the detection requirements of the country.

[0006] The utility model provides an improved full-range active power factor correction circuit, which comprises:

[0007] rectification filter module, BOOST module, detection switching module and PFC modulation module;

[0008] The rectification filter module is connected with the BOOST module, the detection switching module and the PFC modulation module, and the PFC modulation module is connected with the BOOST module and the detection switching module.

[0009] Preferably,

[0010] The rectification filter module comprises an alternating voltage L end, an alternating voltage N end, a rectification bridge BD1 and a capacitor CX1.

[0011] The alternating voltage L end and the alternating voltage N end are connected with the rectification bridge BD1, and the rectification bridge BD1 is connected with the capacitor CX1.

[0012] Preferably,

[0013] The rectification bridge BD1 comprises a diode D4, a diode D5, a diode D6 and a diode D7.

[0014] The alternating voltage L end is connected with the negative electrode of the diode D4 and the positive electrode of the diode D6, and the alternating voltage N end is connected with the negative electrode of the diode D5 and the positive electrode of the diode D7.

[0015] The negative electrode of the diode D6 and the negative electrode of the diode D7 are connected with the capacitor CX1.

[0016] The positive electrode of the diode D4 and the positive electrode of the diode D5 are connected with the capacitor CX1 and a ground wire.

[0017] Preferably,

[0018] The BOOST module comprises a boost inductor L1, a diode D1, a diode D2, a switch tube Q1, a capacitor C1, a resistor R1 and a resistor R2.

[0019] The pin 1 of the boost inductor L1 is connected with the capacitor CX1 and the positive electrode of the diode D1, the pin 2 of the boost inductor L1 is connected with the positive electrode of the diode D2 and the pin 1 of the switch tube Q1, the pin 3 of the boost inductor L1 is connected with the resistor R9, and the pin 4 of the boost inductor L1 is connected with a ground wire.

[0020] The negative electrode of the diode D1 and the negative electrode of the diode D2 are connected with the capacitor C1 and the resistor R4, and the capacitor C1 is connected with the resistor R1 and a ground wire.

[0021] The pin 2 of the switch tube Q1 is connected with the resistor R1, the resistor R2 and the resistor R10, and the pin 3 of the switch tube Q1 is connected with the resistor R2 and the resistor R8.

[0022] Preferably,

[0023] The detection switching module comprises an alternating current terminal, a capacitor CX2, a capacitor C9, a capacitor C10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a sampling resistor RS1, a switch tube Q2, an error amplifier U3B, a comparator U3A, a diode D3 and an optical coupler U2.

[0024] Pin 5 of the error amplifier U3B is connected with the resistor R17, pin 6 of the error amplifier U3B is connected with the resistor R18 and the resistor R16, pin 7 of the error amplifier U3B is connected with the resistor R16 and the resistor R14, the resistor R17 is connected with the sampling resistor RS1 and the alternating current terminal, and the sampling resistor RS1 is connected with the resistor R18 and the ground wire.

[0025] Pin 3 of the comparator U3A is connected with the resistor R14, pin 2 of the comparator U3A is connected with the resistor R15, pin 1 of the comparator U3A is connected with the resistor R13, and pin 8 of the comparator U3A is connected with the capacitor C10 and pin 1 of the optical coupler U2.

[0026] Pin 2 of the optical coupler U2 is connected with the resistor R13, pin 4 of the optical coupler U2 is connected with the negative electrode of the diode D3, the capacitor C9, the resistor R11, the resistor R12 and pin 3 of the switch tube Q2, pin 3 of the optical coupler U2 is connected with the positive electrode of the diode D3, the capacitor C9, the resistor R11 and pin 2 of the switch tube Q2, and pin 1 of the switch tube Q2 is connected with the capacitor CX2.

[0027] The resistor R12 and the capacitor CX2 are connected with the capacitor CX1 and the resistor R7.

[0028] Preferably,

[0029] The comparator U3A and the error amplifier U3B adopt a double operational amplifier LM358.

[0030] Preferably,

[0031] The PFC modulation module comprises a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10 and a PFC controller U1.

[0032] Pin 1 of the PFC controller U1 is connected with the resistor R4, the capacitor C5, the capacitor C4 and the resistor R5, the capacitor C4 is connected with the resistor R3, pin 2 of the PFC controller U1 is connected with the resistor R3 and the capacitor C5, pin 3 of the PFC controller U1 is connected with the capacitor C6, the resistor R6 and the resistor R7, pin 4 of the PFC controller U1 is connected with the resistor R10 and the capacitor C7, pin 5 of the PFC controller U1 is connected with the resistor R9, pin 6 of the PFC controller U1 is connected with the capacitor C7, the resistor R5, the capacitor C6, the resistor R6 and the ground wire, pin 7 of the PFC controller U1 is connected with the resistor R8, pin 8 of the PFC controller U1 is connected with the capacitor C3.

[0033] Preferably,

[0034] The model of the PFC controller U1 is L6562 or EG6562.

[0035] The utility model has the following beneficial effects:

[0036] The error amplifier U3B and the comparator U3A in the detection switching module convert the output current into voltage and compare with the reference voltage Vref; under the condition of large load of the power supply, the harmonic current generated under the large load is reduced by controlling the switch tube Q2 to be turned on; under the condition of small load of the power supply, the light load power factor is improved by controlling the switch tube Q2 to be turned off, the active PFC circuit makes the power factor > 0.8 in the full power range; the circuit of the utility model realizes the full-range power factor correction function, also realizes the functions of light load high power factor and reducing the input end harmonic component when heavy load, and the active PFC circuit is optimized by using the simplified design circuit, can meet the detection requirement and field application, has good reliability and universality. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The principle diagram of the improved full-range active power factor correction circuit;

[0038] 1-rectification filtering module, 2-BOOST boost module, 3-detection switching module, 4-PFC modulation module;

[0039] The realization, functional characteristics and advantages of the utility model will be further explained by combining with embodiments and referring to the drawings. DETAILED DESCRIPTION

[0040] It should be understood that the specific embodiments described herein are only used to explain the utility model and not used to limit the utility model.

[0041] Referring to Figure 1 The utility model provides a kind of improved full-range active power factor correction circuit, comprising:

[0042] Rectification filter module, BOOST module, detection switching module and PFC modulation module;

[0043] Rectification filter module is connected with BOOST module, detection switching module and PFC modulation module, and PFC modulation module is connected with BOOST module and detection switching module.

[0044] As an embodiment:

[0045] Rectification filter module includes AC voltage L end, AC voltage N end, rectifier bridge BD1 and capacitor CX1.

[0046] AC voltage L end and AC voltage N end are connected with rectifier bridge BD1, and rectifier bridge BD1 is connected with capacitor CX1.

[0047] Specifically, when input L, N is connected with AC voltage, AC voltage is rectified through rectifier bridge BD1 and then filtered through CX1 capacitor, and the input end of active PFC power factor correction circuit is obtained.

[0048] As an embodiment:

[0049] Rectifier bridge BD1 includes diode D4, diode D5, diode D6 and diode D7.

[0050] AC voltage L end is connected with negative electrode of diode D4 and positive electrode of diode D6, and AC voltage N end is connected with negative electrode of diode D5 and positive electrode of diode D7.

[0051] Negative electrode of diode D6 and negative electrode of diode D7 are connected with capacitor CX1.

[0052] Positive electrode of diode D4 and positive electrode of diode D5 are connected with capacitor CX1 and ground wire.

[0053] As an embodiment:

[0054] BOOST module includes boost inductor L1, diode D1, diode D2, switch tube Q1, capacitor C1, resistor R1 and resistor R2.

[0055] Pin 1 of boost inductor L1 is connected with capacitor CX1 and positive electrode of diode D1, pin 2 of boost inductor L1 is connected with positive electrode of diode D2 and pin 1 of switch tube Q1, pin 3 of boost inductor L1 is connected with resistor R9, and pin 4 of boost inductor L1 is connected with ground wire.

[0056] Negative electrode of diode D1 and negative electrode of diode D2 are connected with capacitor C1 and resistor R4, and capacitor C1 is connected with resistor R1 and ground wire.

[0057] Pin 2 of switch tube Q1 is connected with resistor R1, resistor R2 and resistor R10, pin 3 of switch tube Q1 is connected with resistor R2 and resistor R8.

[0058] Specifically, the boost circuit composed of boost inductor L1, diode D2 and switch tube Q1 outputs stable DC voltage to the power supply of the subsequent DC / DC converter, at the same time, the PFC controller U1 samples input voltage, inductor current and output voltage, and then controls the on and off of switch tube Q1 after processing in the PFC controller U1, so as to keep input current and input voltage in the same phase of sine wave as much as possible, and achieve the purpose of high power factor.

[0059] As an embodiment:

[0060] The detection switching module comprises: an alternating current end, a capacitor CX2, a capacitor C9, a capacitor C10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a sampling resistor RS1, a switch tube Q2, an error amplifier U3B, a comparator U3A, a diode D3 and an optical coupler U2.

[0061] Pin 5 of error amplifier U3B is connected with resistor R17, pin 6 of error amplifier U3B is connected with resistor R18 and resistor R16, pin 7 of error amplifier U3B is connected with resistor R16 and resistor R14, resistor R17 is connected with sampling resistor RS1 and alternating current end, sampling resistor RS1 is connected with resistor R18 and ground wire.

[0062] Pin 3 of comparator U3A is connected with resistor R14, pin 2 of comparator U3A is connected with resistor R15, pin 1 of comparator U3A is connected with resistor R13, pin 8 of comparator U3A is connected with capacitor C10 and pin 1 of optical coupler U2.

[0063] Pin 2 of optical coupler U2 is connected with resistor R13, pin 4 of optical coupler U2 is connected with negative electrode of diode D3, capacitor C9, resistor R11, resistor R12 and pin 3 of switch tube Q2, pin 3 of optical coupler U2 is connected with positive electrode of diode D3, capacitor C9, resistor R11 and pin 2 of switch tube Q2, pin 1 of switch tube Q2 is connected with capacitor CX2.

[0064] Resistor R12 and capacitor CX2 are connected with capacitor CX1 and resistor R7.

[0065] Specifically, under the condition of large load, the output current flows through the sampling resistor RS1, is converted into a voltage value, is amplified by the error amplifier U3B, and then enters the non-inverting input terminal of the comparator U3A, and is compared with the reference voltage Vref. At this time, the detected output current signal is large, and the voltage after amplification by the error amplifier is higher than the reference voltage. Therefore, the 1 pin of the comparator U3A outputs a high level, controls the photoelectric coupler U2 to be turned off, and makes the gate-source voltage of the switch tube Q2 be the voltage division of the resistors R12 and R11. The switch tube Q2 is turned on, and the capacitor CX2 is connected to the circuit. At this time, there are two capacitors CX1 and CX2 in the circuit, which filter out the differential mode signal and reduce the harmonic current generated under large load. Under light load, the output current is small, and the output current value is amplified by the error amplifier U3B and then enters the non-inverting input terminal of the comparator U3A, and is compared with the reference voltage. At this time, the detected output current signal is small, and the voltage after amplification by the error amplifier is lower than the reference voltage. Therefore, the 1 pin of the comparator U3A outputs a low level, controls the photoelectric coupler U2 to be turned on, and makes the gate-source voltage of the switch tube Q2 be low. The switch tube Q2 is turned off, and the capacitor CX2 is disconnected in the circuit. At this time, there is only one filter capacitor CX1 in the circuit, and the bus voltage detected by the PFC controller U1 through R6 and R7 is closer to the actual input voltage. The effect of the modulation current of the PFC controller U1 is better, so as to improve the power factor under light load.

[0066] As an embodiment:

[0067] The comparator U3A and the error amplifier U3B use a dual operational amplifier LM358.

[0068] As an embodiment:

[0069] The PFC modulation module comprises capacitors C3, C4, C5, C6, C7, resistors R3, R4, R5, R6, R7, R8, R9, R10, and a PFC controller U1.

[0070] The pin 1 of the PFC controller U1 is connected with the resistor R4, the capacitor C5, the capacitor C4, and the resistor R5. The capacitor C4 is connected with the resistor R3. The pin 2 of the PFC controller U1 is connected with the resistor R3 and the capacitor C5. The pin 3 of the PFC controller U1 is connected with the capacitor C6, the resistor R6, and the resistor R7. The pin 4 of the PFC controller U1 is connected with the resistor R10 and the capacitor C7. The pin 5 of the PFC controller U1 is connected with the resistor R9. The pin 6 of the PFC controller U1 is connected with the capacitor C7, the resistor R5, the capacitor C6, the resistor R6, and the ground wire. The pin 7 of the PFC controller U1 is connected with the resistor R8. The pin 8 of the PFC controller U1 is connected with the capacitor C3.

[0071] As an embodiment:

[0072] The model of the PFC controller U1 is L6562 or EG6562.

[0073] It is to be noted that the terms "comprising", "including", and any other variant thereof, are intended to cover a non-exclusive inclusion, such that processes, methods, articles, or systems that comprise a list of elements do not include only those elements but can also include other elements not expressly listed or inherent to such processes, methods, articles, or systems. Without further limitation, an element defined by the statement "comprising a" does not exclude the existence of additional identical elements in the process, method, article, or system including the element.

[0074] The above-mentioned embodiment serial numbers of the utility model are only for description, and do not represent the advantages and disadvantages of the embodiments. In the unit claims of several enumerated devices, several of the devices can be embodied by the same hardware item. The use of the words first, second, and third does not represent any order, and the words can be interpreted as identifiers.

[0075] The above is only the preferred embodiment of the utility model, and does not limit the patent range of the utility model, and any equivalent structure or equivalent process transformation using the content of the utility model specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection range of the utility model.

Claims

1. An improved full range active power factor correction circuit, characterized by, The improved full-range active power factor correction circuit comprises a rectification filtering module, a BOOST voltage-boosting module, a detection switching module and a PFC modulation module. The rectification filtering module is connected with the BOOST voltage-boosting module, the detection switching module and the PFC modulation module, and the PFC modulation module is connected with the BOOST voltage-boosting module and the detection switching module.

2. The improved full-range active power factor correction circuit according to claim 1, wherein the rectification filtering module comprises an AC voltage L terminal, an AC voltage N terminal, a rectification bridge BD1 and a capacitor CX1. The AC voltage L terminal and the AC voltage N terminal are connected with the rectification bridge BD1, and the rectification bridge BD1 is connected with the capacitor CX1.

3. The improved full-range active power factor correction circuit according to claim 2, wherein the rectification bridge BD1 comprises a diode D4, a diode D5, a diode D6 and a diode D7. The AC voltage L terminal is connected with the negative electrode of the diode D4 and the positive electrode of the diode D6, and the AC voltage N terminal is connected with the negative electrode of the diode D5 and the positive electrode of the diode D7. The negative electrode of the diode D6 and the negative electrode of the diode D7 are connected with the capacitor CX1. The positive electrode of the diode D4 and the positive electrode of the diode D5 are connected with the capacitor CX1 and a ground wire.

4. The improved full-range active power factor correction circuit according to claim 1, wherein the BOOST voltage-boosting module comprises a voltage-boosting inductor L1, a diode D1, a diode D2, a switching tube Q1, a capacitor C1, a resistor R1 and a resistor R2. The pin 1 of the voltage-boosting inductor L1 is connected with the capacitor CX1 and the positive electrode of the diode D1, the pin 2 of the voltage-boosting inductor L1 is connected with the positive electrode of the diode D2 and the pin 1 of the switching tube Q1, the pin 3 of the voltage-boosting inductor L1 is connected with a resistor R9, and the pin 4 of the voltage-boosting inductor L1 is connected with a ground wire. The negative electrode of the diode D1 and the negative electrode of the diode D2 are connected with the capacitor C1 and a resistor R4, and the capacitor C1 is connected with the resistor R1 and a ground wire. The pin 2 of the switching tube Q1 is connected with the resistor R1, the resistor R2 and a resistor R10, and the pin 3 of the switching tube Q1 is connected with the resistor R2 and a resistor R8.

5. The improved full-range active power factor correction circuit according to claim 1, wherein the detection switching module comprises an AC current terminal, a capacitor CX2, a capacitor C9, a capacitor C10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a sampling resistor RS1, a switching tube Q2, an error amplifier U3B, a comparator U3A, a diode D3 and an optical coupler U2. The pin 5 of the error amplifier U3B is connected with the resistor R17, the pin 6 of the error amplifier U3B is connected with the resistor R18 and the resistor R16, the pin 7 of the error amplifier U3B is connected with the resistor R16 and the resistor R14, the resistor R17 is connected with the sampling resistor RS1 and the AC current terminal, and the sampling resistor RS1 is connected with the resistor R18 and a ground wire. ​ ​ ​ ​ ​ Pin 3 of comparator U3A is connected with resistor R14, pin 2 of comparator U3A is connected with resistor R15, pin 1 of comparator U3A is connected with resistor R13, pin 8 of comparator U3A is connected with capacitor C10 and pin 1 of optocoupler U2; Pin 2 of optocoupler U2 is connected with resistor R13, pin 4 of optocoupler U2 is connected with negative pole of diode D3, capacitor C9, resistor R11, resistor R12 and pin 3 of switch tube Q2, pin 3 of optocoupler U2 is connected with positive pole of diode D3, capacitor C9, resistor R11 and pin 2 of switch tube Q2, pin 1 of switch tube Q2 is connected with capacitor CX2; Resistor R12 and capacitor CX2 are connected with capacitor CX1 and resistor R7.

6. The improved full-range active power factor correction circuit according to claim 5, characterized in that: Comparator U3A and error amplifier U3B adopt dual operational amplifier LM358.

7. The improved full-range active power factor correction circuit according to claim 1, characterized in that: The PFC modulation module comprises capacitor C3, capacitor C4, capacitor C5, capacitor C6, capacitor C7, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10 and PFC controller U1; Pin 1 of PFC controller U1 is connected with resistor R4, capacitor C5, capacitor C4 and resistor R5, capacitor C4 is connected with resistor R3, pin 2 of PFC controller U1 is connected with resistor R3 and capacitor C5, pin 3 of PFC controller U1 is connected with capacitor C6, resistor R6 and resistor R7, pin 4 of PFC controller U1 is connected with resistor R10 and capacitor C7, pin 5 of PFC controller U1 is connected with resistor R9, pin 6 of PFC controller U1 is connected with capacitor C7, resistor R5, capacitor C6, resistor R6 and ground wire, pin 7 of PFC controller U1 is connected with resistor R8, pin 8 of PFC controller U1 is connected with capacitor C3.

8. The improved full-range active power factor correction circuit according to claim 7, characterized in that: The model of PFC controller U1 is L6562 or EG6562.

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