Single-phase voltage-multiplying power factor correction circuit

Abstract

A single-phase voltage-multiplying power factor correction circuit comprises an alternating current power supply Ug, an inductor L1, an inductor L2, diodes D1-D6, a switching tube S, a capacitor C1, a capacitor C2, a capacitor C3 and a load RL. The capacitor C3, the capacitor C2, the diode D5 and the inductor L2 form a voltage-multiplying unit. The invention provides a single-phase voltage-multiplying power factor correction circuit which is provided with fewer power tubes, and the voltage stress of a switching tube and one diode and the current stress of the other diode and the inductor are obviously reduced. Meanwhile, compared with a traditional boost conversion circuit which cannot provide high voltage gain due to parasitic resistance in the circuit, the boost conversion circuit combines the advantages of a voltage-multiplying power factor correction circuit, so that the voltage gain is improved, the system loss and cost are reduced, and the conversion efficiency is improved.

Description

Technical Field

[0001] The present invention relates to a single-phase power factor correction circuit, and particularly to a single-phase voltage-doubling type power factor correction circuit. Background Art

[0002] With the rapid development of renewable energy, large-scale renewable energy power generation systems need to be connected to traditional power systems, and the power system has higher and higher requirements for the quality of electric energy conversion. After years of development, traditional power factor correction circuits have formed technical routes represented by basic topologies such as Boost, Buck, and Buck-Boost. Among them, the Boost power factor correction circuit has become the mainstream solution due to its advantages such as simple structure and continuous input current. However, with the growth of new energy equipment, high-density power supply systems, and wide voltage adaptation requirements, the deficiencies of traditional power factor correction circuits in terms of performance, efficiency, and adaptability have gradually emerged, which are specifically manifested in the following aspects:

[0003] 1. In a traditional Boost power factor correction circuit, the peak voltage borne by its switching tube is usually 1.5 to 2 times the output voltage. When the output voltage requirement is high, such as above 400V, the withstand voltage level of the switching device is significantly increased, which not only increases the cost of semiconductor devices, but also increases the conduction loss due to the increase in on-resistance and forward voltage drop.

[0004] 2. The voltage gain (output voltage / input voltage) of a traditional Boost power factor correction circuit can reach infinity under ideal conditions. However, due to the limitation of the parasitic resistance in the boost inductor and power device, the actual boost ability of the Boost power factor correction circuit is very limited.

[0005] 3. To reduce voltage / current stress, traditional solutions adopt a multi-stage cascade or interleaved parallel structure. However, it is necessary to multiply the number of switching tubes and diodes, resulting in a significant increase in system complexity and cost. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a single-phase voltage-doubling type power factor correction circuit, which has fewer diodes, and the voltage stress of the switching tube and one diode, as well as the current stress of the other diode and one inductor, are significantly reduced; and a voltage-doubling unit is used to achieve voltage doubling. This new type of power factor correction circuit not only has the characteristics of high efficiency, stability, and flexibility; at the same time, the voltage-doubling unit can also be designed and adjusted according to needs to adapt to different input and output voltage requirements.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A single-phase voltage-doubling type power factor correction circuit, comprising: an AC power supply U g, inductors L1, L2, diodes D1 to D6, switching transistor S, capacitors C1, C2, C3, load R L ;

[0009] Power supply U g One end of which is respectively connected to the anode of diode D1 and the cathode of diode D3, and commonly connected to node a;

[0010] Power supply U g The other end is respectively connected to the anode of diode D2 and the cathode of diode D4, and commonly connected to node b;

[0011] The cathode of diode D1 is respectively connected to the cathode of diode D2 and one end of inductor L1, and commonly connected to node c;

[0012] The anode of diode D3 is respectively connected to the anode of diode D4, the source of switching transistor S, the negative electrode of capacitor C2, the negative electrode of capacitor C1, load R L The other end of which is connected, and commonly connected to node d;

[0013] The other end of inductor L1 is respectively connected to the drain of switching transistor S, the anode of diode D5, and the negative electrode of capacitor C3, and commonly connected to node e;

[0014] The cathode of diode D5 is respectively connected to the positive electrode of capacitor C2 and one end of inductor L2, and commonly connected to node g;

[0015] The anode of diode D6 is respectively connected to the other end of inductor L2 and the positive electrode of capacitor C3, and commonly connected to node h;

[0016] The cathode of diode D6 is respectively connected to the positive electrode of capacitor C1 and one end of load R L The other end of which is connected, and commonly connected to node p.

[0017] The capacitor C3, capacitor C2, diode D5, and inductor L2 are connected to form a voltage multiplier unit.

[0018] In this circuit, the four diodes D1, D2, D3, and D4 in the rectifier bridge can all be replaced with switching transistors containing anti-parallel diodes such as MOSFE or IGB or IGC, which can improve the rectification efficiency, reduce power consumption and voltage loss, and at the same time have good controllability, reverse blocking ability and heat dissipation performance.

[0019] This circuit includes two working modes:

[0020] Mode 1: The switching transistor S is turned on, the current flows through the inductor L1, and then returns to the power supply U after the switching transistor S1 g ; At this time, the power supply U g Charges the inductor L1; The capacitor C3 charges the capacitor C2 through the inductor L2; The capacitor C1 supplies power to the load RL Charging; the current in inductors L1 and L2 linearly rises from zero;

[0021] Mode 2: The switch tube S is turned off. Inductor L1 charges the load through diode D5, inductor L2, and diode D5; capacitor C2 charges capacitor C1 through inductor L2 and diode D6; at this time, inductor L1 continues to charge the load R L Charging; the current in inductors L1 and L2 starts to linearly decline.

[0022] In the two operating modes, the capacitor voltage U1 = U2 + U3 = U dc , where U1 is the voltage of capacitor C1, U2 is the voltage of capacitor C2, U3 is the voltage of capacitor C3, and U dc is the DC load output voltage.

[0023] The single-phase voltage-doubling power factor correction circuit of the present invention has the following beneficial effects:

[0024] 1) The power factor correction circuit of the present invention itself has the functions of boosting and rectifying. The voltage stress and current stress borne by the switch tube and some diodes are relatively low. By combining the voltage-doubling unit, this single-phase voltage-doubling power factor correction circuit can boost the input single-phase AC voltage several times.

[0025] 2) The present invention adopts a quasi-Z-source network to form a voltage-doubling unit. By multiplexing LC elements, while realizing the voltage-doubling function, the number of additional diodes is reduced. The voltage multiplication is achieved, and it has the advantages of high efficiency, stability, and flexibility. At the same time, the current of the front-stage inductor of this single-phase voltage-doubling power factor correction circuit is shunted through the Z-source network, and the effective value of the current of a single inductor is reduced, alleviating the problems of heating and volume of magnetic components.

[0026] 3) This power factor correction circuit has fewer diodes, and the voltage stress of the switch tube and one diode, as well as the current stress of another diode and one inductor, are significantly reduced. This new type of power factor correction circuit reduces system losses and costs, improves conversion efficiency, and also extends the service life of the rectification unit. Description of the Drawings

[0027] The present invention will be further described below in conjunction with the drawings and examples;

[0028] Figure 1 is the schematic diagram of the principle of a single-phase voltage-doubling power factor correction circuit of the present invention.

[0029] Figure 2 is the schematic diagram of the current path of the single-phase voltage-doubling power factor correction circuit in operating mode 1.

[0030] Figure 3Schematic diagram of the current path in operating mode 2 of a single-phase voltage-doubling power factor correction circuit.

[0031] Figure 4 For the input voltage U of a single-phase voltage-doubling power factor correction circuit g and current i g Waveform diagram.

[0032] Figure 5 For the output DC voltage U of a single-phase voltage-doubling power factor correction circuit dc Waveform diagram.

[0033] Figure 6 For the output DC voltage U of a single-phase voltage-doubling power factor correction circuit when the load is halved dc Waveform diagram. Specific implementation

[0034] As Figure 1 shown, a single-phase voltage-doubling power factor correction circuit includes:

[0035] AC power supply U g , inductor L1, inductor L2, diodes D1 - D6, switching transistor S, capacitor C1, capacitor C2, capacitor C3, load R L ;

[0036] One end of the power supply U g is respectively connected to the anode of diode D1 and the cathode of diode D3, and commonly connected to node a;

[0037] The other end of the power supply U g is respectively connected to the anode of diode D2 and the cathode of diode D4, and commonly connected to node b;

[0038] The cathode of diode D1 is respectively connected to the cathode of diode D2 and one end of inductor L1, and commonly connected to node c;

[0039] The anode of diode D3 is respectively connected to the anode of diode D4, the source of switching transistor S, the negative electrode of capacitor C2, the negative electrode of capacitor C1, and the other end of load R L and commonly connected to node d;

[0040] The other end of inductor L1 is respectively connected to the drain of switching transistor S, the anode of diode D5, and the negative electrode of capacitor C3, and commonly connected to node e;

[0041] The cathode of diode D5 is respectively connected to the positive electrode of capacitor C2 and one end of inductor L2, and commonly connected to node g;

[0042] The anode of diode D6 is respectively connected to the other end of inductor L2 and the positive electrode of capacitor C3, and commonly connected to node h;

[0043] The cathode of diode D6 is respectively connected to the positive electrode of capacitor C1 and one end of load R L and are commonly connected to node p.

[0044] The capacitor C3, capacitor C2, diode D5, and inductor L2 are connected to form a voltage multiplier unit.

[0045] The following describes the power factor correction circuit of the present invention, the specific working principle of a single-phase voltage multiplier type power factor correction circuit. The single-phase voltage multiplier type power factor correction circuit has 2 working modes, where the capacitor voltage U1 = U2 + U3 = U dc , and the specific analysis process is as follows:

[0046] Figure 2 Schematic diagram of the current path for Mode 1: The switching transistor S is turned on, and the current flows through inductor L1, switching transistor S1 and then returns to power supply U g ; at this time, power supply U g charges inductor L1; capacitor C3 charges capacitor C2 through inductor L2; capacitor C1 charges load R L ; the currents in inductors L1 and L2 start to linearly rise from zero;

[0047] Figure 3 Schematic diagram of the current path for Mode 2: The switching transistor S is turned off, and inductor L1 charges the load through diode D5, inductor L2, and diode D5; capacitor C2 charges capacitor C1 through inductor L2 and diode D6; at this time, inductor L1 continues to charge load R L ; the currents in inductors L1 and L2 start to linearly decrease;

[0048] Table 1 is the corresponding relationship table of the switching transistor pulse distribution mode, DC-side inductor, and capacitor operating states of the power factor correction circuit. Among them, the on and off of the switching transistor are represented by "1" and "0" respectively.

[0049] Table 1 Corresponding relationship table of the switching transistor pulse distribution mode, DC-side inductor, and capacitor operating states

[0050]

[0051] To verify that a single-phase voltage multiplier type power factor correction circuit of the present invention can achieve the voltage multiplication function, under the hysteresis control strategy, experimental verification is carried out. Experimental parameters: RMS input voltage 220V, operating frequency 50Hz, inductor L1 is 0.58mH, inductor L2 is 1.08mH, capacitor C1 is 3500uF, capacitor C2 is 250uF, capacitor C3 is 160uF, switching frequency 20kHz, load 100Ω.

[0052] Figure 4 For the input voltage U of the single-phase voltage multiplier type power factor correction circuitg and the current i g Waveform diagram. By controlling the on and off of the switch converter, the present invention makes the input current waveform as close to a sine wave as possible, which can further reduce the harmonic content of the grid-side current. As shown in the Figure 4 waveform, the voltage and current are in the same phase, that is, the power factor correction function is achieved.

[0053] Figure 5 is the waveform diagram of the output DC voltage U of the single-phase voltage-doubling power factor correction circuit. dc Waveform diagram. The present invention designs a single-phase voltage-doubling power factor correction circuit with an input of 220V and an output of 800V, which consists of Figure 5 As can be seen from the waveform, the voltage U is dc doubled.

[0054] Figure 6 is the waveform diagram of the output DC voltage U when the load of the single-phase voltage-doubling power factor correction circuit is halved. dc Waveform diagram. When the load suddenly decreases from 100Ω to 50Ω at 0.4s and returns to 100Ω at 0.5s, the output DC voltage U dc waveform is slightly adjusted from 0.4s to 0.5s and quickly returns to the stable state, indicating that the single-phase voltage-doubling power factor correction circuit system under the PR control strategy has strong dynamic regulation ability and good anti-disturbance performance.

[0055] A single-phase voltage-doubling power factor correction circuit proposed by the present invention has fewer power transistors, and the voltage stress of the switching transistor and a diode, as well as the current stress of another diode and the inductor, are significantly reduced. At the same time, compared with the traditional boost converter, which cannot provide a high voltage gain due to the parasitic resistance in the circuit, this circuit combines the advantages of the voltage-doubling power factor correction circuit, thereby improving the voltage gain, reducing the system loss and cost, and improving the conversion efficiency.

Claims

1. A single-phase voltage doubling power factor correction circuit, characterized in that include: AC power supply U g , inductor L1, inductor L2, diodes D1~D6, switch tube S, capacitor C1, capacitor C2, capacitor C3, load R L ; Power supply g One end of is respectively connected to the anode of diode D1 and the cathode of diode D3, and are connected to node a together; Power supply g The other end is connected to the anode of diode D2 and the cathode of diode D4 respectively, and connected to node b together; The cathode of the diode D1 is connected to the cathode of the diode D2 and one end of the inductor L1 respectively, and they are connected together to the node c; The anode of diode D3 is connected to the anode of diode D4, the source of switch tube S, the cathode of capacitor C2, the cathode of capacitor C1, and the load R L The other end of is connected to the node d; The other end of the inductor L1 is respectively connected to the drain of the switch tube S, the anode of the diode D5, and the negative electrode of the capacitor C3, and are connected to the node e; The cathode of the diode D5 is connected to the positive electrode of the capacitor C2 and one end of the inductor L2 respectively, and they are connected together to the node g; The anode of the diode D6 is connected to the other end of the inductor L2 and the positive electrode of the capacitor C3, and they are connected to the node h; the cathode of the diode D6 is connected to the positive electrode of the capacitor C1 and the load R L One end of is connected to each other and are connected to the node p.

2. A single-phase voltage doubling power factor correction circuit according to claim 1, characterized in that: The capacitor C3, the capacitor C2, the diode D5, and the inductor L2 are connected to form a voltage doubling unit.

3. A single-phase voltage doubling power factor correction circuit according to claim 1, characterized in that: In this circuit, the four diodes D1, D2, D3, and D4 in the rectifier bridge can be replaced by switching tubes of MOSFE, IGB, or IGC containing anti-parallel diodes.

4. The single-phase voltage doubling power factor correction circuit according to claim 1, characterized in that: The circuit includes two working modes: Mode 1: The switch tube S is turned on, the current flows through the inductor L1, and then returns to the power supply U after the switch tube S1. g ; At this time, the power supply U g Charges the inductor L1; the capacitor C3 charges the capacitor C2 through the inductor L2; the capacitor C1 charges the load R L Charging; the current in inductors L1 and L2 rises linearly from zero; Mode 2: Switch S is turned off, inductor L1 charges the load through diode D5, inductor L2, and diode D5; capacitor C2 charges capacitor C1 through inductor L2 and diode D6; at this time, inductor L1 continues to charge the load R L Charging; the current in inductors L1 and L2 begins to decrease linearly.

5. A single-phase voltage doubling power factor correction circuit according to claim 4, characterized in that: In the two working modes, the capacitor voltage U1=U2+U3=U dc , where U1 is the voltage of capacitor C1, U2 is the voltage of capacitor C2, U3 is the voltage of capacitor C3, and U dc is the DC load output voltage.

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