CN105553249B - Wide voltage range low voltage stress current injection type three-phase power factor correction circuit - Google Patents

Abstract

The present invention relates to a kind of wide-voltage range low voltage stress current-injecting three-phase power factor correcting circuits, according to input voltage working range, circuit is operable with boost patterns, is also operable with buck patterns, the voltage stress of switching tube is than directly using typical buck topology（buck‑boost、cuk、sepic、zeta）It is small, there is higher conversion efficiency.The converter of the present invention controls the corresponding phase voltage of current tracking of maximum, the minimum phase of input voltage instantaneous value respectively；According to three-phase symmetrical, in addition a phase current also follows its phase voltage, to realize that three-phase current sineization controls.By operating mode stage by stage, output voltage can rise to drop the circuit, input and output voltage can working range it is big, be suitable for the big application scenario of input and output voltage variation range.The present invention is without complicated vector controlled, as long as using DC/DC PWM control technologies, so that it may to realize three-phase input current positizing string, it is easy to accomplish.

Description

Wide voltage range low voltage stress current injection type three-phase power factor correction circuit

technical field

The invention relates to a wide voltage range low voltage stress current injection type three-phase power factor correction circuit.

Background technique

Harmonic current input from the grid side will lead to low utilization of the power system, large losses, affect the normal operation of electrical equipment and even endanger the stable operation of the entire power grid. A number of harmonic limitation standards regulate the harmonic content of electrical equipment. Such as IEC61000-3-2, GB17625.1 and other standards clearly stipulate the harmonic current limit of electronic equipment, and only electronic equipment that meets the requirements of the specification is allowed to be listed.

The electrical equipment with a power of more than 5 kW usually adopts high-power electrical equipment powered by three phases, which generates large harmonic pollution, but PFC technology has not been widely used, mainly because the development of three-phase PFC technology is not mature enough. The system structure and control are complex and difficult to realize. The most common three-phase PFC circuit structure is a PWM rectifier, which can be divided into two categories: voltage-type PWM rectifier and current-type PWM rectifier. The former is a step-up structure, the output DC voltage must be greater than the peak value of the three-phase input line voltage, and the device voltage stress is large. For domestic Ull=380V (400V in Europe) industrial electricity, the output DC voltage generally reaches 700~800V; 480V (or 600V) power supply in North America, the output voltage is higher. The current-mode PWM rectifier is a step-down structure, and the output voltage . The VIENNA rectifier that appeared in recent years is a step-up structure, and the SWISS rectifier is a step-down structure. Most of the three-phase PFC circuits known at present are a single step-up or step-down structure, and some three-phase PFC circuits with a step-up and step-down function The voltage stress of the PFC circuit device is too large, the control is complicated, and the practical application is difficult. In applications where the output voltage is not within the above range, or where the input and output voltages vary widely, a circuit with a single step-up or step-down function cannot meet the requirements.

Contents of the invention

In view of this, the object of the present invention is to provide a three-phase power factor correction circuit with a wide voltage range and low voltage stress current injection, which solves the problem that the output voltage can only be raised or lowered in a single way and the voltage stress of existing circuit devices is too large .

In order to achieve the above object, the present invention adopts the following technical scheme: a wide voltage range low voltage stress current injection type three-phase power factor correction circuit, characterized in that it includes a three-phase AC input power supply Uin, a three-phase rectifier bridge DB1, a power MOSFET Tube S1, power MOSFET tube S2, power MOSFET tube S3, power MOSFET tube S4, diode D1, diode D2, diode D3, harmonic current injection network, inductor L1, inductor L2, output filter capacitor Cf and load; the harmonic The current injection network includes a bidirectional switch Sy1, a bidirectional switch Sy2 and a bidirectional switch Sy3; the three input phase voltages of the three-phase AC input power supply Uin are respectively connected to the three input terminals of the three-phase rectifier bridge DB1, and the three-phase AC input The three input phase voltages of the power supply Uin are also respectively connected with one end of the bidirectional switch Sy1, one end of the bidirectional switch Sy2, and one end of the bidirectional switch Sy3; the other end of the bidirectional switch Sy1, the other end of the bidirectional switch Sy2 and the The other end is connected to the injection point Y; the positive output terminal of the three-phase rectifier bridge DB1 is connected to the drain of the power MOSFET S1, and the negative output terminal of the three-phase rectifier bridge DB1 is connected to the source of the power MOSFET S2; The source of the power MOSFET S1 is connected to the cathode of the diode D1 and one end of the inductor L1, the drain of the power MOSFET S2 is connected to the anode of the diode D2 and one end of the inductor L2; the other end of the inductor L1 is connected to the drain of the power MOSFET S3 pole and the anode of the diode D3, the other end of the inductor L2 is connected to the source of the power MOSFET S4, the negative pole of the output filter capacitor Cf and one end of the load RL, the cathode of the diode D3 is connected to the positive pole of the output filter capacitor Cf and the load RL The other end is connected; the anode of the diode D1, the cathode of the diode D2, the source of the power MOSFET S3 and the drain of the power MOSFET S4 are connected to the injection point Y.

Further, the power MOSFET S1 and the power MOSFET S2 may be IGBT power switch tubes.

Further, the power MOSFET S3 and the power MOSFET S4 are IGBT power switch tubes with anti-parallel fast recovery power diodes.

Further, the diode D1, the diode D2, and the diode D3 are fast recovery power diodes.

Further, the bidirectional switch Sy1, the bidirectional switch Sy2 and the bidirectional switch Sy3 are formed by two power MOSFETs or two IGBTs in reverse series.

Further, the working modes of the inductor L1 and the inductor L2 are continuous inductor current CCM, inductor current discontinuous DCM or inductor current critical BCM.

Further, the output filter capacitor Cf is an energy storage electrolytic capacitor.

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

1. The present invention operates with different circuits in different stages, the output voltage can be raised or lowered, and the input and output voltage has a large working range, which is more suitable for applications with a large input and output voltage variation range;

2. The voltage stress of the switching tube of the present invention is small, and at any stage, only two switching tubes work in a high-frequency state, and the switching loss is small, which is conducive to improving efficiency;

3. The present invention does not require complicated vector control, and can realize sinusoidal sinusoidal input current as long as DC/DC PWM control technology is adopted, which is easy to realize.

Description of drawings

Fig. 1 is the concrete implementation circuit diagram of the present invention.

FIG. 2 is a timing diagram of driving signals of three bidirectional switches and three-phase input power of the present invention.

Fig. 3 is a voltage and current waveform diagram when the present invention works in a steady state.

Fig. 4 is an equivalent circuit diagram of the present invention in interval ①, boost working mode.

FIG. 5 is a simplified circuit diagram of FIG. 4 .

Fig. 6a is a current path diagram of stage 1 when the present invention is in interval ①, boost working mode.

Fig. 6b is a current path diagram of phase 2 of the present invention in interval ① and boost working mode.

Fig. 6c is a current path diagram of stage 3 of the present invention in interval ①, boost working mode.

Fig. 6d is a current path diagram of stage 4 in the section ① of the present invention, boost working mode.

Fig. 7 is an equivalent circuit diagram of the present invention in interval ①, buck working mode.

FIG. 8 is a simplified circuit diagram of FIG. 7 .

Fig. 9a is a current path diagram of stage 1 in section ① and buck working mode of the present invention.

Fig. 9b is a current path diagram of phase 2 of the present invention in section ① and buck working mode.

Fig. 9c is a current path diagram of stage 3 in the section ① of the present invention, buck working mode.

Fig. 9d is a current path diagram of stage 4 in the section ① of the present invention, buck working mode.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Please refer to Fig. 1, the present invention provides a wide voltage range low voltage stress current injection type three-phase power factor correction circuit, which is characterized in that it includes a three-phase AC input power supply Uin, a three-phase rectifier bridge DB1, a power MOSFET tube S1, a power MOSFET tube S2, power MOSFET tube S3, power MOSFET tube S4, diode D1, diode D2, diode D3, harmonic current injection network, inductor L1, inductor L2, output filter capacitor Cf and load; the harmonic current injection network includes Bidirectional switch Sy1, bidirectional switch Sy2 and bidirectional switch Sy3; the three input phase voltages of the three-phase AC input power supply Uin are respectively connected to the three input terminals of the three-phase rectifier bridge DB1, and the three input terminals of the three-phase AC input power supply Uin Each input phase voltage is also connected with one end of bidirectional switch Sy1, one end of bidirectional switch Sy2, and one end of bidirectional switch Sy3; the other end of described bidirectional switch Sy1, the other end of bidirectional switch Sy2 and the other end of bidirectional switch Sy3 are connected to Injection point Y; the positive output terminal of the three-phase rectifier bridge DB1 is connected to the drain of the power MOSFET S1, and the negative output terminal of the three-phase rectifier bridge DB1 is connected to the source of the power MOSFET S2; the power MOSFET S1 The source of the diode D1 is connected to the cathode of the diode D1 and one end of the inductor L1, the drain of the power MOSFET S2 is connected to the anode of the diode D2 and one end of the inductor L2; the other end of the inductor L1 is connected to the drain of the power MOSFET S3 and the diode D3 The anode of the inductance L2 is connected to the anode, the other end of the inductor L2 is connected to the source of the power MOSFET S4, the negative pole of the output filter capacitor Cf and one end of the load RL, and the cathode of the diode D3 is connected to the positive pole of the output filter capacitor Cf and the other end of the load RL; The anode of the diode D1, the cathode of the diode D2, the source of the power MOSFET S3 and the drain of the power MOSFET S4 are connected to the injection point Y.

In Figure 1, power MOSFET S1, power MOSFET S2, diode D1, diode D2, inductor L1, inductor L2, and output filter capacitor Cf constitute two buck circuits; power MOSFET S3, power MOSFET S4, diode D3, and inductor L1 , inductor L2, and output filter capacitor Cf form two boost circuits.

In this embodiment, the power MOSFET S1 and the power MOSFET S2 may be IGBT power switch tubes.

In this embodiment, the power MOSFET S3 and the power MOSFET S4 are IGBT power switch tubes with anti-parallel fast recovery power diodes.

In this embodiment, the diode D1, the diode D2, and the diode D3 are fast recovery power diodes.

In this embodiment, the bidirectional switch Sy1 , the bidirectional switch Sy2 and the bidirectional switch Sy3 are formed by two power MOSFETs or two IGBTs in reverse series.

In this embodiment, the working modes of the inductors L1 and L2 are continuous inductor current CCM, inductor current discontinuous DCM, or inductor current critical BCM.

In this embodiment, the output filter capacitor Cf is an energy storage electrolytic capacitor.

As shown in FIG. 2 , it is a time sequence diagram of the driving signal of the switching tube of the harmonic current injection network and the three-phase input power of the present invention. The relationship between the control signals of the three bidirectional switches Sy1, Sy2, and Sy3 and the instantaneous value of the three-phase input voltage, the bidirectional switch injected into the branch works at twice the power supply frequency, and belongs to the low frequency working power switch tube. An AC power cycle is divided into 6 intervals, and each interval is 60°. In each interval, the corresponding bidirectional switch with the smallest absolute value of the three-phase input voltage is turned on. Figure 3 shows the voltage and current waveforms during steady-state operation. u _pY and u _Yn are segmental combinations of line voltages, similar to triangular waves. The following analysis takes interval ① as an example to analyze the detailed working process of boost mode and buck mode respectively. In this interval, the absolute value of the phase c voltage is the smallest, the bidirectional switch Sy3 is turned on, and Sy1 and Sy2 are turned off. The maximum voltage of phase a is positive, u _pN = u _aN , and the minimum voltage of phase b is negative, u _nN = u _bN . From this we can know that u _pn = u _ab , u _pY = u _ac , u _Yn = u _cb , u _pn = u _ab .

One: boost mode

When the three-phase rectified output voltage u _pn < U _o , the circuit works in boost mode. Referring to Figure 4, power MOSFETs S1 and S2 are kept on at this time, and power MOSFETs S3 and S4 are switched at high frequency. The simplified equivalent circuit is shown in Figure 5, and the arrows indicate the reference positive direction of each state variable. The S3 and S4 control signals are modulated by the trailing edge, that is, they are turned on simultaneously at the beginning of each switching cycle.

(1) S3 and S4 are turned on at the same time, and the equivalent circuit is shown in Figure 6a. The voltage u _pY = u _ac is added to L1; the voltage u _Yn = u _cb is added to L2; i _L1 and i _L2 increase. D3 is reverse-biased, and the load RL is powered by the capacitor C _f .

(2) S3 is turned on and S4 is turned off, the equivalent circuit is shown in Figure 6b. S3 turns on, i _L1 increases; i _L2 passes through S3 (when i _L2 > i _L1 , through S3 parasitic diode), D3 freewheeling discharge, and decreases under the action of back pressure ( U _o - u _Yn ).

(3) S3 is turned off and S4 is turned on, and the equivalent circuit is shown in Figure 6c. S4 turns on, i _L2 increases; i _L1 passes through S4 (when i _L1 > i _L2 , through S4 parasitic diode), D3 freewheeling discharge, and decreases under the action of back pressure ( U _o - u _pY ).

(4) S3 and S4 are turned off at the same time, and the equivalent circuit is shown in Figure 6d. The actual conduction loop is divided into three situations, a) At the moment when S3 and S4 are turned off at the same time, i _L1 > i _L2 , then i _Y <0, S4 parasitic diode Ds4 conducts, and i _L2 continues to increase under the action of u _Yn , i _L1 decreases under backpressure ( U _o − u _pY ). If i _L1 = i _L2 before the next switching cycle arrives, the parasitic diodes of S3 and S4 are not connected, i _Y =0, and the freewheeling flow of i _L1 and i _L2 decreases together. b) When S3 and S4 are turned off at the same time, i _L1 < i _L2 , then i _Y >0, the parasitic diode Ds3 of S3 is turned on, i _L1 continues to increase under the action of u _pY , and i _L2 is under the back pressure ( U _o - u _Yn ) decreases under the action. If i _L1 = i _L2 before the next switching cycle arrives, the parasitic diodes of S3 and S4 are not connected, i _Y =0, and the freewheeling flow of i _L1 and i _L2 decreases together. c) At the moment when S3 and S4 are turned off at the same time, i _L1 = i _L2 , it will directly transfer to the state where the parasitic diodes of S3 and S4 are not connected, i _Y =0, and the freewheeling current of i _L1 and i _L2 decreases together.

When the power MOSFET S3 is turned on, the current i _L1 of the inductor L1 increases; when S3 is turned off, the i _L1 decreases; the current i _L1 of the inductor L1 can be controlled by controlling the on and off of the S3, and the current of the inductor L1 is a Phase current, i _p = i a = i _L1 . Therefore, it is possible to make i _a track the a-phase voltage u _a by controlling the on-off of the power MOSFET tube S3. In the same way, i _b can track the b-phase voltage u _b by controlling the on-off of the power MOSFET S4, i _n = i _b =- i _L2 . According to the node current equation at point Y, c-phase current i _c = i _Y = i _L2 - i _L1 =-( i _a + i _b ), when the three phases are symmetrical, if i _a and i _b track their respective phase voltage u _{a , ub , then ic also tracks the phase voltage uc} , so that the three-phase input current tracks the _three -phase _input voltage. It can be seen that the voltage stress of power MOSFET tubes S3 and S4 is the output voltage U _o .

Two: buck mode

When the three-phase rectified output voltage u _pn > U _o , the circuit works in buck mode. Referring to accompanying drawing 7, power MOSFET tube S3, S4 keeps turning off at this moment, power MOSFET tube S1, S2 high-frequency switching operation, simplified equivalent circuit is shown in Figure 8, and the arrow indicates the reference positive direction of each state variable, because L1 , L2 are always connected in series, so i _L1 = i _L2 = i _L . The S1 and S2 control signals are modulated by the trailing edge, that is, they are turned on simultaneously at the beginning of each switching cycle.

(1) S1 and S2 are turned on at the same time, and the current path is shown in Figure 9a. The voltage ( u _pn - U _o ) is applied to L1 and L2, i _L rises, and supplies power to the energy storage capacitor C _f and the load RL at the same time.

(2) S1 is turned on, S2 is turned off, and the current path is shown in Figure 9b. If u _pY > U _o , then i _L increases; otherwise, i _L decreases.

(3) S1 is turned off, S2 is turned on, and the current path is shown in Figure 9c. If u _nY > U _o , then i _L increases; otherwise, i _L decreases.

(4) S1 and S2 are turned off at the same time, and the current path is shown in Figure 9d. The back pressure U _o is added to L1 and L2, and the freewheeling flow of i _L decreases.

When the power MOSFET S1 is turned on, the power MOSFET S1 current i _S1 = i _L ; when S1 is turned off, i _S1 =0; the S1 current i S1 can be controlled by controlling the on and off of _S1 , at this time i _S1 = i _p = i _a , so it is possible to make i _a track the a-phase voltage u _a by controlling the on-off of the power MOSFET S1. In the same way, i _b can track the b-phase voltage u _b by controlling the on-off of the power MOSFET S2, - i _S2 = i _n = i _b . According to the node current equation at point Y, i _c = i _Y = i _S2 - i _S1 =-( i _a + i _b ), when the three phases are symmetrical, if i _a and i _b track their respective phase voltages u _a and u _b , then ic also tracks _the phase voltage uc , so that the three-phase input current tracks the three-phase _input voltage. The voltage stress of power MOSFET tubes S1 and S2 is the maximum value of the three-phase rectified output voltage u _pn .

The working conditions of other intervals are similar to the working state of interval ①. From a complete power cycle, the three-phase input current tracks the three-phase input voltage. It can be seen from Figure 3 _{that ip} tracks the voltage u _pN between the positive output terminal of the three-phase rectifier bridge and the neutral line of the power supply, _and in tracks the voltage u _nN between the negative output terminal of the three-phase rectifier bridge and the neutral line of the power supply , i _Y is an approximate triangular wave of three times the power supply frequency.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (7)

1. a kind of wide-voltage range low voltage stress current-injecting three-phase power factor correcting circuit, it is characterised in that：Including Three-phase alternating current input power Uin, three-phase commutation bridge DB1, power MOSFET tube S1, power MOSFET tube S2, power MOSFET tube S3, power MOSFET tube S4, diode D1, diode D2, diode D3, harmonic current injection network, inductance L1, inductance L2, Output filter capacitor Cf and load；The harmonic current injection network includes two-way switch Sy1, two-way switch Sy2 and two-way opened Close Sy3；Three of three-phase alternating current input power Uin input phase voltages respectively with three input terminals of three-phase commutation bridge DB1 Connection, three of three-phase alternating current input power Uin input phase voltages also respectively with one end of two-way switch Sy1, two-way opened Close one end of Sy2, one end connection of two-way switch Sy3；The other end of the two-way switch Sy1, the other end of two-way switch Sy2 And the other end of two-way switch Sy3 is connected in decanting point Y；The positive output end and power MOSFET tube of the three-phase commutation bridge DB1 The drain electrode of S1 connects, and the negative output terminal of the three-phase commutation bridge DB1 is connect with the source electrode of power MOSFET tube S2；Power MOSFET The source electrode of pipe S1 is connect with one end of the cathode of diode D1 and inductance L1, and the drain electrode of power MOSFET tube S2 is with diode D2's One end of anode and inductance L2 connect；The other end of inductance L1 connects with the anode of the drain electrode of power MOSFET tube S3 and diode D3 It connects, the other end of inductance L2 and one end of the source electrode of power MOSFET tube S4, the cathode of output filter capacitor Cf and load RL connect It connects, the cathode of diode D3 is connect with the other end of the anode of output filter capacitor Cf and load RL；The anode of diode D1, two The drain electrode of the cathode of pole pipe D2, the source electrode of power MOSFET tube S3 and power MOSFET tube S4 is connected in the decanting point Y.

2. wide-voltage range low voltage stress current-injecting three-phase power factor correcting circuit according to claim 1, It is characterized in that：The power MOSFET tube S1 and power MOSFET tube S2 is IGBT power switch tubes.

3. wide-voltage range low voltage stress current-injecting three-phase power factor correcting circuit according to claim 1, It is characterized in that：The power MOSFET tube S3 and power MOSFET tube S4 or to restore power diode soon with inverse parallel IGBT power switch tubes.

4. wide-voltage range low voltage stress current-injecting three-phase power factor correcting circuit according to claim 1, It is characterized in that：The diode D1, diode D2, diode D3 are fast recovery power diodes.

5. wide-voltage range low voltage stress current-injecting three-phase power factor correcting circuit according to claim 1, It is characterized in that：The two-way switch Sy1, two-way switch Sy2 and two-way switch Sy3 are by two power MOSFET tubes or two IGBT pipe differential concatenations form.

6. wide-voltage range low voltage stress current-injecting three-phase power factor correcting circuit according to claim 1, It is characterized in that：The operating mode of the inductance L1 and inductance L2 is continuous current mode CCM, discontinuous current mode DCM or electricity The critical BCM of inducing current.

7. wide-voltage range low voltage stress current-injecting three-phase power factor correcting circuit according to claim 1, It is characterized in that：The output filter capacitor Cf is energy storage electrolytic capacitor.