CN110880864A - Single-phase five-level power factor correction circuit based on hybrid H bridge - Google Patents

Abstract

A single-phase five-level power factor correction circuit based on a hybrid H-bridge, including switch tubes Q ₁ , Q ₂ , Q ₃ , one side of the AC power supply Vs is connected to the anode of diode D ₁ and the cathode of diode D ₂ respectively, and the connection node constitutes terminal b The other side of the AC power supply Vs is connected to one end of the inductor L, the other end of the inductor L is connected to the anode of the diode _D3 and the cathode of the diode D4 respectively, and the connection node forms the terminal _a ; the drain of the switch tube _Q3 is connected to the cathode of the diode D1 and the diode _D3 respectively _{. The} cathode, the anode of the diode D7, the drain _of the switch Q1 are connected to the node to form the terminal c _; the source of the switch _Q3 is _respectively connected to the anode of the diode D2, the anode of the diode D4, the cathode of the diode _D8 , and the source of the switch _Q2 , The connection node constitutes the terminal d; the source of the switch _Q2 is connected to the drain _of the switch Q1, and its connection node constitutes the terminal n; the cathode of the diode _D7 is connected to _one end of the capacitor C1, and its connection node constitutes the terminal _p ; the cathode of the capacitor C2 is connected to the diode D ₈ anode, its connecting node constitutes terminal m. The endpoint a, the endpoint c, the endpoint d, and the endpoint n form the four ports of the hybrid H-bridge network structure. The circuit structure of the invention has the advantages of low cost, high reliability and simple control system design.

Description

Single-phase five-level power factor correction circuit based on hybrid H-bridge

technical field

The invention relates to a power factor correction circuit, in particular to a single-phase five-level power factor correction circuit based on a hybrid H-bridge.

Background technique

With the development of power electronics technology, the research and application of multi-level power factor correction circuits have received extensive attention, and the five-level high power factor boost converter is one of the most popular research aspects. The five-level high power factor correction circuit needs to meet the requirements of unity power factor, low harmonic content and DC side voltage stability; traditional five-level power factor correction circuits mostly use diode clamp circuits and flying capacitor clamp circuits to achieve five-level power factor correction. Flat output, its structure is complex, and the control system design is difficult; at the same time, the reliability and performance of the five-level power factor circuit based on the diode clamp type and the flying capacitor type are poor.

SUMMARY OF THE INVENTION

The purpose of the present invention is mainly to address that the existing five-level topological structures are mostly symmetrical H-bridge structures, and this type of structure has disadvantages such as many controllable devices, difficult control system design, and insufficient reliability. A single-phase five-level power factor correction circuit based on a hybrid H-bridge is proposed, which has the advantages of low cost, high reliability and simple control system design. In this way, the circuit volume is reduced to a certain extent, the switching loss is reduced, and the power density is improved.

The technical scheme adopted in the present invention is:

A single-phase five-level power factor correction circuit based on a hybrid H-bridge includes an inductor L, switch tubes Q ₁ , Q ₂ , Q ₃ , diodes D ₁ to D ₉ , and capacitors C ₁ and C ₂ ;

_One side of the AC power supply Vs is respectively connected to the anode of the diode D1 and the cathode of the diode D2, and the connection node constitutes the terminal b _;

The other side of the AC power supply Vs is connected to one end of the inductor L, and the other end of the inductor L is connected to the anode of the diode _D3 and the cathode of the diode D4 respectively _; the other end of the inductor L and the connection node of the diodes _D3 and _D4 form the endpoint a;

The drain of the switch tube _Q3 is respectively connected to the cathode of the diode D1, the cathode _of the diode _D3 , the anode of the diode _D7 , and the drain of the switch tube Q1 _; the drain of the switch tube _Q3 is connected to the diodes _D1 , _D3 , _D7 , and the switch tube Q ₁ The connection node of the drain constitutes the terminal c;

The source of the switch _Q3 is _respectively connected to the anode of the diode D2, the anode of the diode D4, the cathode of the diode _D8 , and the source of the switch _{Q2 ;} the source of the switch _Q3 is connected to the diodes _D2 , _D4 , _D8 , and the switch Q. ₂ The connection node of the source constitutes the terminal d;

The source electrode of the switch tube _Q2 is connected to the drain electrode _of the switch tube Q1, and its connection node constitutes the end point n;

_The cathode of the diode D7 is connected to _one end of the capacitor C1, and its connection node constitutes the terminal p;

The other end of the capacitor _C1 is connected to one end of the capacitor _C2 , and the connection point is connected to the terminal n;

_The cathode of the capacitor C2 is connected to the anode of the diode _D8 , and its connection node constitutes the terminal m;

The switch tube Q1 has _an anti-parallel diode D ₅ , the switch tube Q ₂ has an anti-parallel diode D ₆ , and the switch tube Q ₃ has an anti-parallel diode D ₉ ;

The endpoint p and the endpoint m are respectively connected to both ends of the load _RL .

The endpoint a, the endpoint c, the endpoint d, and the endpoint n form a four-port hybrid H-bridge network structure, and the two sides of the hybrid H-bridge are divided into diodes and full control devices.

The switching transistors Q ₁ , Q ₂ and Q ₃ are insulated gate bipolar transistors IGBT, integrated gate commutated thyristor IGCT, or power field effect transistor MOSFET.

The capacitors C ₁ and C ₂ are series-connected DC bus split capacitors.

A single-phase five-level power factor correction circuit based on a hybrid H bridge of the present invention has the following technical effects:

1: Single-phase five-level power factor correction circuit based on hybrid H-bridge, structural innovation: This five-level topology integrates diodes and fully-controlled devices, invents a highly reliable hybrid H-bridge four-terminal network structure, using fully-controlled switches The tube realizes the selection of the power path, and uses the diodes D ₇ and D ₈ to realize the unidirectional flow of the DC bus power. This inventive topology also has the characteristics of boost boost, rectification, and five-level power factor correction.

2: The present invention proposes a single-phase five-level power factor correction circuit based on a hybrid H-bridge. The new topology is a hybrid H-bridge four-port network structure, and the hybrid H-bridge-based circuit module can be used as a five-level module. the power unit.

3: The hybrid H-bridge five-level topology is integrated into the unity power factor correction circuit topology; the boost process is introduced into the rectifier topology, and the fusion technology of fully controlled and uncontrolled devices is applied to make it structurally modular In addition, the single-phase five-level power factor correction circuit based on the hybrid H-bridge has been applied to the body diode of the switch as a conduction loop for many times, and in the case of the loss of the switch-on pulse It can still supply power to the load normally, reduce the failure loss to a certain extent, and improve the working reliability of the single-phase five-level power factor correction circuit.

4: The hybrid H-bridge structure in the circuit of the present invention has high reliability, few driving circuits, and has the characteristics of boosting, rectifying, and five-level power factor correction at the same time. In addition, the topology of the present invention mostly uses diode devices that do not need to be controlled to cooperate with each other to achieve five. The design of the control system of the circuit is relatively simple and feasible, and the invention is suitable for application in medium and small power occasions.

5: The hybrid H-bridge structure proposed by the present invention has the advantages of less driving circuits and high reliability; in addition, diode devices are mostly used without control to cooperate with each other to complete the five-level. The topology is suitable for small and medium power applications. This topology has the characteristics of boosting, rectifying, and five-level power factor correction at the same time.

6: In order to ensure that the topology of the present invention is widely used in industry, the topology of the present invention adopts a dual-loop PI control mode, adopts voltage as the control amount of the outer loop, and current is used as the inner loop control. The current waveform is greatly distorted.

Description of drawings

Below in conjunction with accompanying drawing and embodiment, the present invention will be further described:

FIG. 1 is a circuit topology structure 1 of the present invention.

FIG. 2 is a flow diagram of the switching mode of the present invention.

FIG. 3 is a second flow diagram of the switching mode of the present invention.

FIG. 4 is a three-flow diagram of the switching mode of the present invention.

FIG. 5 is a four-flow diagram of the switching mode of the present invention.

FIG. 6 is a flow diagram of five switching modes of the present invention.

FIG. 7 is a six-flow diagram of the switching mode of the present invention.

FIG. 8 is a block diagram of the control strategy of the present invention.

FIG. 9 is a voltage waveform diagram of the input voltage V _ab of the topological rectifier of the present invention.

FIG. 10 is a topological input voltage and current waveform diagram of the present invention.

FIG. 11 is a waveform diagram of the DC side voltage and current of the topology output of the present invention.

Detailed ways

As shown in FIG. 1 , the single-phase five-level power factor correction circuit based on the hybrid H-bridge includes an inductor L, switch tubes Q ₁ , Q ₂ , Q ₃ , diodes D ₁ to D ₉ , and capacitors C ₁ and C ₂ ;

_One side of the AC power supply Vs is respectively connected to the anode of the diode D1 and the cathode of the diode D2, and the connection node constitutes the terminal b _;

The other side of the AC power supply Vs is connected to one end of the inductor L, and the other end of the inductor L is connected to the anode of the diode _D3 and the cathode of the diode D4 respectively _; the other end of the inductor L and the connection node of the diodes _D3 and _D4 form the endpoint a;

The drain of the switch tube _Q3 is respectively connected to the cathode of the diode D1, the cathode _of the diode _D3 , the anode of the diode _D7 , and the drain of the switch tube Q1 _; the drain of the switch tube _Q3 is connected to the diodes _D1 , _D3 , _D7 , and the switch tube Q ₁ The connection node of the drain constitutes the terminal c;

The source of the switch _Q3 is _respectively connected to the anode of the diode D2, the anode of the diode D4, the cathode of the diode _D8 , and the source of the switch _{Q2 ;} the source of the switch _Q3 is connected to the diodes _D2 , _D4 , _D8 , and the switch Q. ₂ The connection node of the source constitutes the terminal d;

The source electrode of the switch tube _Q2 is connected to the drain electrode _of the switch tube Q1, and its connection node constitutes the end point n;

_The cathode of the diode D7 is connected to _one end of the capacitor C1, and its connection node constitutes the terminal p;

The other end of the capacitor _C1 is connected to one end of the capacitor _C2 , and the connection point is connected to the terminal n;

_The cathode of the capacitor C2 is connected to the anode of the diode _D8 , and its connection node constitutes the terminal m;

The switch tube Q1 has _an anti-parallel diode D ₅ , the switch tube Q ₂ has an anti-parallel diode D ₆ , and the switch tube Q ₃ has an anti-parallel diode D ₉ ;

The endpoint p and the endpoint m are respectively connected to both ends of the load _RL .

The endpoint a, the endpoint c, the endpoint d, and the endpoint n form a four-port hybrid H-bridge network structure, and the two sides of the hybrid H-bridge are divided into diodes and full control devices. The new topology is a four-port network structure in a hybrid H-bridge type, which can be used as a five-level modular power unit module.

The switching transistors Q ₁ , Q ₂ and Q ₃ are insulated gate bipolar transistors IGBT, integrated gate commutated thyristor IGCT, or power field effect transistor MOSFET.

电平的抬升。The capacitors C ₁ and C ₂ are series-connected DC bus splitting capacitors. The splitting capacitor is formed by two capacitors with the same capacitance value connected in series. It can be known from the voltage division of the capacitors in series that the capacitors with the same capacitance value in series can bear half of the series voltage, which is mainly To divide the voltage of the DC side to construct the midpoint of half of the bus voltage, the purpose is to complete the

level rise.

As shown in Figure 1, the current i _l is the inductor output current, i _dc is the load current output value, and V _dc is the output voltage value at both ends of the load _RL . The topology uses the switching tube MOSFET anti-parallel diode as the conduction of the circuit for many times. circuit, saving design cost to a certain extent.

A single-phase five-level power factor correction circuit based on a hybrid H-bridge, including the following switching modes:

Switching mode 1: As shown in Figure ₂ , this time is the positive half cycle of the AC power supply Vs, the switch _Q3 is turned on, the current passes through the inductor L, the switch _Q3 , and finally flows back through the diodes D2 and _D3 . This process The inductor L stores energy, and the load R _L is powered by the capacitors C ₁ and C ₂ ;

Switching mode ₂ : As shown in Figure 3, this time is the positive half cycle of the AC power supply Vs, the switch tube Q1 is turned _on , and the current passes through the inductor L, the diodes _D3 , _D8 , D2 and the capacitor _C2 . During this process, The AC power supply Vs and the inductor L charge the capacitor C ₂ at the same time, and the load _RL is powered by the capacitor C _1. The switching process of switching mode 1 and switching mode 2 is a Boost boosting process;

Switching mode 3: As shown in Figure 4, this time is the positive half cycle of the AC power supply Vs, the current passes through the inductor L, the diodes D ₃ , D ₇ , D ₈ , D ₂ and the capacitors C ₁ , C ₂ , during this process, the AC The power supply Vs and the inductor L supply power to the load _RL and the capacitors C ₁ and C ₂ at the same time, and the capacitors C ₁ and C ₂ are charged;

Switch mode ₄ : As shown in Figure 5, this time is the negative half cycle of the AC power supply Vs, the switch _Q3 is turned _on , the current passes through the diodes D1, D4, the switch _Q3 , and finally returns to the AC power supply Vs through the inductor L , in this process, the inductor L stores energy, and the load _RL is powered by the capacitors C ₁ and C ₂ ;

Switching mode 5: As shown in Figure ₆ , this time is the negative half cycle of the AC power supply Vs, the switch tube _Q2 is turned _on , and the current passes through the diodes D1, _D8 , D4, _D7 , and the split capacitor _C1 , and finally, The inductance L flows back to the AC power supply Vs. During this process, the AC power supply Vs and the inductor L charge the capacitor _C1 at the same time. The conversion process from switch mode four to switch mode five is a Boost boosting process;

Switching mode 6: As shown in Figure 7, this time is the negative half cycle of the AC power supply Vs, the current passes through the diodes D ₁ , D ₄ , D ₇ , D ₈ and the capacitors C ₁ , C ₂ , and returns to the AC power supply Vs through the inductor L , during this process, the AC power supply Vs and the inductor L supply power to the load _RL and the capacitors C ₁ and C ₂ at the same time, and the capacitors C ₁ and C ₂ are charged.

8 is a block diagram of the control strategy adopted by the topology structure of the present invention. The double closed-loop PI control method of the topology structure of the present invention realizes closed-loop system control, wherein the voltage is used as the outer-loop control of the control loop, the current is used as the inner-loop control mode, and the current inner-loop is used. The main reason for the control is to realize the sinusoidal current waveform. At the same time, the output of the current inner loop obtains a reference voltage vector through the input and output function expression of the equivalent circuit, which is used as the control parameter of the pulse width modulation wave. , using a phase-locked loop (PLL) to realize the control of another reference input voltage as the input of the modulating wave.

Experimental parameters:

The peak value of the AC power supply is 220V, the output DC voltage v _dc is 250V, the resistive load is 40Ω, the filter inductance is 2mH, the split capacitor C ₁ =C ₂ =1000μF, and the switching frequency is 100kHz. The topology control method is implemented as shown in Figure 8, and can be obtained from the steady-state loop voltage equation of the topology:

Among them, L is the linear inductance L=2mH, r is the equivalent resistance of the inductance r=0.3Ω, λ and γ are a switching function quantity 0<γ, λ<1, the pull transformation of formula (1) can be obtained:

From the proposed steady-state loop current equation, we can get:

i _l = i _c + i _dc (3)

k为一个开关比例系数0<k<1。in

k is a switch proportional coefficient 0<k<1.

Pull transformation of equation (4) can be obtained:

The main function of the voltage outer loop is to stabilize the output voltage of the DC bus, and at the same time provide a reference current value for the inner loop. The voltage outer loop realizes voltage stability through PI control. The voltage outer loop transfer function:

Wherein k _pv is the proportional coefficient of the voltage loop PI, and k _pv =10, k _iv is the integral coefficient of the voltage loop PI, and k _iv =0.01.

The main purpose of the application of the current inner loop is to sinusoidal the input current, and the reference current value of the inner loop is obtained by multiplying the output value of the voltage outer loop and the output of the phase-locked loop. The current loop PI transfer function:

Wherein k _pc is the current loop PI proportional coefficient, and k _pc =10, k _ic is the current loop PI integral coefficient, and k _ic =0.1.

It can be seen from the control block diagram that the current loop transfer function is:

Then the closed-loop transfer function of the control system is:

9 to 11 are the experimental waveforms of the present invention when the medium load is 40 ohms.

Fig. 9 is a voltage waveform diagram in the series branch of the AC power supply and the inductor. It can be clearly seen in Fig. 9 that the V _ab voltage achieves five-point leveling, which verifies the correctness of the topology of the present invention, that is, the present invention can realize the single-phase three-tube five-electrical Flat power factor correction.

FIG. 10 is a waveform diagram of voltage and current on the input side of the AC power supply. It can be seen that the voltage and current are in the same phase, and the waveform verifies that the topology of the present invention can realize the function of single-phase power factor correction.

Figure 11 is a waveform diagram of the output voltage and current of the topology rectification. From Figure 11, it can be seen that the voltage and current changes in the waveform diagram are consistent to achieve a stable voltage function.

Use diodes D ₇ , D ₈ for circuit protection as follows:

First, two diodes D ₇ and D ₈ are used to ensure the unidirectional flow of power, and to ensure that the currents of the capacitors C ₁ and C ₂ will only flow to the load _RL , and will not cause it to flow backwards;

Second, when the circuit fails, it can be well protected;

Third, in the process of mode switching, it acts as a boost voltage clamping diode;

Fourth, in switching mode 1 and switching mode 4, when the voltage of the inductance L is lower than the voltage of the capacitors C ₁ and C ₂ during the energy storage process, it acts as a voltage clamp.

Claims (7)

1. A single-phase five-level power factor correction circuit based on a hybrid H bridge comprises an inductor L and a switching tube Q₁、Q₂、Q₃Diode D₁～D₉Capacitor C₁、C₂(ii) a The method is characterized in that:

one side of the AC power supply Vs is respectively connected with a diode D₁Anode, diode D₂A cathode, the connection node constituting a terminal b;

the other side of the AC power supply Vs is connected with one end of an inductor L, and the other end of the inductor L is respectively connected with a diode D₃Anode, diode D₄A cathode; the other end of the inductor L and the diode D₃、D₄The connection nodes of (a) form an endpoint a;

switch tube Q₃The drain electrodes are respectively connected with a diode D₁Cathode, diode D₃Cathode, diode D₇Anode and switch tube Q₁A drain electrode; switch tube Q₃Drain and diode D₁、D₃、D₇And a switching tube Q₁The connection node of the drain forms an end point c;

switch tube Q₃The source electrodes are respectively connected with a diode D₂Anode, diode D₄Anode, diode D₈Cathode and switch tube Q₂A source electrode; switch tube Q₃Source and diode D₂、D₄、D₈And a switching tube Q₂The connection node of the source electrode forms an end point d;

switch tube Q₂Source electrode connecting switch tube Q₁A drain connected to the node to form an end point n;

diode D₇Cathode connection capacitor C₁One end, the connection node of which constitutes an endpoint p;

capacitor C₁The other end is connected with a capacitor C₂One end, the connecting point is connected with the endpoint n;

capacitor C₂Cathode connection diode D₈An anode, the connection node of which forms an endpoint m;

switch tube Q₁Anti-parallel diode D₅Switching tube Q₂Anti-parallel diode D₆Switching tube Q₃Anti-parallel diode D₉；

The end point p and the end point m are respectively connected with a load R_LTwo ends.

2. The hybrid H-bridge based single-phase five-level power factor correction circuit of claim 1, wherein: the end point a, the end point c, the end point d and the end point n form four ports of a hybrid H-bridge network structure, and bridge arms on two sides of the hybrid H-bridge are divided into diodes and full-control devices.

3. The hybrid H-bridge based single-phase five-level power factor correction circuit of claim 1, wherein: the switch tube Q₁、Q₂、Q₃Is an insulated gate bipolar transistor IGBT, an integrated gate commutated thyristor IGCT, or a power field effect transistor MOSFET.

4. The hybrid H-bridge based single-phase five-level power factor correction circuit of claim 1, wherein: the capacitor C₁、C₂The split capacitors are connected in series with a direct current bus.

5. The single-phase five-level power factor correction circuit based on a hybrid H-bridge of any of claims 1-4, comprising the following switching modes:

a first switching mode: at this time, the positive half cycle of the AC power supply Vs, the switch tube Q₃Conducting, current passing through inductor L and switching tube Q₃Finally via a diode D₂、D₃Flowing back, in the process, the inductor L stores energy and the load R_LBy a capacitor C₁、C₂Supplying power;

and a second switching mode: at this time, the positive half cycle of the AC power supply Vs, the switch tube Q₁Conducting current through inductor L and diode D₃、D₈、D₂And a capacitor C₂In the process, the AC power supply Vs and the inductor L simultaneously couple the capacitor C₂Charging, load R_LBy a capacitor C₁The power supply is realized, and the conversion process of the first switch mode and the second switch mode is a boosting process;

and (3) switching mode III: in this case, the positive half cycle of the AC power source Vs, the current passes through the inductor L and the diode D₃、D₇、D₈、D₂And a capacitor C₁、C₂In the process, the AC power supply Vs and the inductor L simultaneously supply the load R_LAnd a capacitor C₁、C₂Supply, capacitor C₁、C₂Charging;

and a fourth switching mode: at this time, the negative half cycle of the AC power supply Vs, the switch tube Q₃On and current flows through the diode D₁、D₄Switching tube Q₃Finally, the voltage returns to the alternating current power supply Vs through the inductor L, in the process, the inductor L stores energy, and the load R_LBy a capacitor C₁、C₂Supplying power;

a switching mode five: at this time, the negative half cycle of the AC power supply Vs, the switch tube Q₂On and current flows through the diode D₁、D₈、D₄、D₇And a split capacitor C₁Finally, the current flows through the inductor L and returns to the AC power source Vs, and in the process, the AC power source Vs and the inductor L simultaneously supply the capacitor C₁Charging, wherein the conversion process from the switching mode four to the switching mode five is a boosting process;

a switching mode six: in this case, the negative half cycle of the AC source Vs, the current passes through the diode D₁、D₄、D₇、D₈And a capacitor C₁、C₂Returns to the AC power supply Vs through the inductor L, and in the process, the AC power supply Vs and the inductor L simultaneously supply the load R_LAnd a capacitor C₁、C₂Supply, capacitor C₁、C₂And (6) charging.

6. The hybrid H-bridge based single-phase five-level power factor correction circuit of claim 5, wherein: using diodes D₇、D₈The following circuit protection is performed:

one, two diodes D are adopted₇D₈Ensuring one-way circulation of power and ensuring the capacitance C₁、C₂Will only flow to the load R_LFlow without flowing backward;

secondly, when the circuit is in failure, the capacitor C₁、C₂The protection can be well realized;

thirdly, in the mode switching process, the diode is used as a boosting voltage clamping diode;

and fourthly, when the voltage is lower than the voltage of the direct current bus in the energy storage process of the inductor L in the first switching mode and the fourth switching mode, the voltage clamping effect is achieved.

7. The single-phase five-level power factor correction circuit based on a hybrid H-bridge according to any one of claims 1 to 4, characterized in that: the control of a closed-loop system is realized by adopting a double closed-loop PI control method, wherein voltage is used as the outer loop control of a control loop, and current is used as an inner loop control mode;

the current inner loop control is adopted to realize the sine of the current waveform, meanwhile, the output of the current inner loop obtains a reference voltage vector through an equivalent circuit input and output function expression, the reference voltage vector is used as a control parameter of a pulse width modulation wave, and the other reference quantity of the control input voltage is used as the modulation wave input by sampling the voltage of a power grid and adopting a phase-locked loop PLL (phase-locked loop).

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