A single-phase interleaved and three-phase Vienna topology compatible input PFC device

Abstract

The present invention discloses a PFC device compatible with single-phase interleaved and three-phase Vienna topologies for input, which includes a PFC unit and a control unit. The PFC unit includes a boost circuit and a filter circuit coupled to the output of the boost circuit. The input end of the boost circuit is used to be coupled to an external AC power supply, and the output end of the filter circuit is used to be coupled to a load. The control unit includes an input voltage acquisition circuit, a driving circuit, a switching circuit, and a digital signal processing circuit. The digital signal processing circuit controls the switching circuit and the driving circuit based on the acquired voltage value of the input voltage acquisition circuit, so as to control the boost circuit to operate in the single-phase interleaved PFC mode when a single-phase AC power supply is input, and to operate in the three-phase Vienna topology PFC mode when a three-phase AC power supply is input. It solves the convenient needs of electric vehicles for fast charging on highways and timely replenishing electric energy indoors, ensures electrical safety through multiple measures, and achieves the purposes of small size, low cost, and high efficiency.

Description

Technical Field

[0001] The present invention relates to the field of wireless charging, and particularly to a PFC device compatible with single-phase interleaved and three-phase Vienna topologies for input. Background Art

[0002] As the country pays more and more attention to environmental protection and strongly advocates energy conservation, emission reduction, and pollution reduction, new energy vehicles have gradually become the first choice for consumers to travel. Coupled with the national new energy subsidy policy, more and more new energy vehicles have emerged like mushrooms after a spring rain. New energy vehicles are particularly prominent in energy conservation, environmental protection, and zero emissions. In addition, without license plate restrictions, it is more convenient to travel.

[0003] However, problems such as difficult charging and slow charging of new energy vehicles have become bottlenecks in the development of electric vehicles. In particular, problems such as frequent charging, short driving range, and high battery costs of electric buses and large electric vehicles are difficult to solve. In this context, the non-contact method of charging electric vehicles in real time during driving is extremely urgent. However, the magnetic coupling loss between the wireless charging ground coil and the vehicle-mounted coil is large, which requires very low power transmission loss for each stage and a high-efficiency power transmission device. Moreover, users expect the charging device to be able to charge quickly on highways and slowly indoors. Summary of the Invention

[0004] The purpose of the present invention is to provide a PFC device compatible with single-phase interleaved and three-phase Vienna topologies for input. The device aims to solve the convenient need for fast charging on highways and timely power replenishment indoors, and multiple measures are taken to ensure electrical safety, and achieve the goals of small size, low cost, and high efficiency.

[0005] The present invention is implemented by adopting the following technical solutions:

[0006] A PFC device compatible with single-phase interleaved and three-phase Vienna topologies for input includes a PFC unit and a control unit. The PFC unit includes a boost circuit and a filter circuit coupled to its output. The input end of the boost circuit is used to couple to an external AC power supply, and the output end of the filter circuit is used to couple to a load. The control unit includes an input voltage acquisition circuit, a drive circuit, a switching circuit, and a digital signal processing circuit. The input end of the input voltage acquisition circuit is used to acquire the voltage at the input end of the boost circuit, and the output end is coupled to the digital signal processing circuit. The input ends of the drive circuit and the switching circuit are respectively coupled to the digital signal processing circuit, and the output ends are respectively coupled to the boost circuit. The digital signal processing circuit controls the boost circuit to operate in the single-phase interleaved PFC mode when a single-phase AC power supply is input and in the three-phase Vienna topology PFC mode when a three-phase AC power supply is input based on the acquired voltage value of the input voltage acquisition circuit through the switching circuit and the drive circuit.

[0007] Further, there are 4 sets of boost circuits. Each set of boost circuit includes a boost inductor, a first diode and a second diode, a first power transistor and a second power transistor. The filtering circuit includes filtering capacitors C1 - C4. One end of the boost inductor is used to couple to an external AC power supply, and the other end is coupled to the anode of the first diode, the cathode of the second diode, and the drain of the first power transistor. The cathode of the first diode, the positive electrodes of filtering capacitors C1 and C3 are used to couple to the positive input terminal of the load. The anode of the second diode, the negative electrodes of filtering capacitors C2 and C4 are used to couple to the negative input terminal of the load. The source of the first power transistor is coupled to the source of the second power transistor, and the gates of the first power transistor and the second power transistor are coupled to a drive circuit. The drain of the second power transistor of the first set of boost circuits and the drain of the second power transistor of the third set of boost circuits are coupled together as a first pin to couple to a switching circuit. The drain of the second power transistor of the second set of boost circuits and the drain of the second power transistor of the third set of boost circuits are coupled together as a second pin to couple to the switching circuit.

[0008] The boost circuits are shared by the single - phase interleaved PFC mode and the three - phase Vienna topology PFC mode. When operating in the interleaved PFC mode, the first set of boost circuits and the second set of boost circuits are in parallel for inputting L or N of single - phase AC, and the third set of boost circuits and the fourth set of boost circuits are in parallel for inputting N or L of single - phase AC. When operating in the three - phase Vienna mode, the fourth set of boost circuits is left floating.

[0009] Further, the switching circuit includes a switching switch K1 and a switching control circuit. The switching switch K1 includes a first switch and a second switch. Pin 1 of the first switch is coupled to the second output terminal of the boost circuit, pin 2 of the first switch is coupled to pin 2 of the second switch, and pin 1 of the second switch is coupled to the first output terminal of the boost circuit. The input terminal of the switching control circuit is coupled to a digital signal processing circuit, and the output terminal is coupled to the first switch and the second switch. When there is single - phase AC input, it controls the first switch and the second switch to be off. When there is three - phase AC input, it controls the switching switch K1 to be on.

[0010] Further, the switching switch K1 is a single - pole double - throw switch, a relay, or composed of semiconductor switches.

[0011] When the external power input is single - phase alternating current, K1 is off and remains off all the time. When the external power input is three - phase alternating current, K1 is on and remains on all the time.

[0012] Further, the control unit further includes an input current acquisition circuit. The input terminal of the input current acquisition circuit is coupled to the other ends of the boost inductors Lu, Lv, Lw, and Ln of the four sets of boost circuits, and the output terminal is coupled to the digital signal processing circuit for acquiring the input current value after passing through the boost inductor.

[0013] Further, the control unit further includes an output voltage acquisition circuit. The input end of the output voltage acquisition circuit is coupled to the output end of the filtering circuit, and the output end is coupled to the digital signal processing circuit for acquiring the output voltage value.

[0014] Further, it also includes 4 input power terminals for external AC power input. For single-phase AC input, input power terminals 1 and 2 are combined to input AC L, and 3 and 4 are combined to input AC N; for three-phase AC input, input power terminals 1-3 respectively input the three-phase AC U, V, and W, and terminal 4 is left floating.

[0015] When in single-phase AC input, the 4 input power terminals can be manually short-circuited in pairs externally, or the digital signal processing circuit controls the front end of the boost circuit to short-circuit the 4 input power terminals in pairs.

[0016] Further, the power transistor is a metal oxide semiconductor field effect transistor, using NTHL065N65S3, and the diode is a semiconductor diode, using STTH75S12.

[0017] Further, the drive circuit includes a power transistor isolation drive chip, using TLP5754D4-TP, and the digital signal processing circuit includes a DSP, using TMS320F280049.

[0018] Further, the input voltage acquisition circuit includes an input voltage differential acquisition chip, using MC33274ADR2G; the input current acquisition circuit includes an input current isolation detection chip, using ACS730KLCTR-50AV-T.

[0019] The present invention has the following technical advantages or beneficial effects:

[0020] 1. This device adopts a method that can input both single-phase and three-phase power, which is convenient for users to quickly charge when inputting three-phase AC power (such as on highways), and can also meet the dual needs of slow charging when inputting single-phase AC power (such as at home, in public places, etc.). It combines two charging devices into one charging device, reducing a set of charging devices and greatly saving costs.

[0021] 2. This device is a combined device that can be connected to both single-phase AC input voltage and three-phase AC input voltage, integrating the traditional single-phase PFC and three-phase PFC devices together, reducing the volume of the device, lowering the cost, and facilitating the popularization and development of the wireless charging system.

[0022] 3. The rectifier-bridge-free topology eliminates the three-phase rectifier bridge for converting AC to DC at the AC input, reducing the number of three-phase rectifier diodes, saving the losses caused by rectifier diodes, reducing the volume and production cost of the device, decreasing the power device losses, improving the power supply efficiency, reducing the device temperature rise. The three-phase Vienna topology PFC effectively reduces the voltage stress on the power transistors. The single-phase interleaved PFC is adopted, with the average input current being half of the total current. The power transistor switching and conduction losses are small, reducing the cost and extending the product service life, achieving the goal of high efficiency, energy saving, and low cost.

[0023] 4. By detecting the input voltage to control the switching switch to switch the working mode, the safety of power consumption of the wireless charging system is further ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the circuit schematic diagram of the embodiment of the present invention;

[0025] Figure 2 is the circuit schematic diagram of the first implementation manner of the embodiment of the present invention;

[0026] Figure 3 is the circuit schematic diagram of the first group of single-phase interleaved PFC circuits of the embodiment of the present invention;

[0027] Figure 4 is the circuit schematic diagram of the second group of single-phase interleaved PFC circuits of the embodiment of the present invention;

[0028] Figure 5 is the schematic diagram of the on and off circuit principles of the power transistors in the single-phase interleaved PFC mode of the embodiment of the present invention;

[0029] Figure 6 is the circuit schematic diagram of the second implementation manner of the embodiment of the present invention;

[0030] Figure 7 is the schematic diagram of the on circuit principles of the U-phase and V-phase power transistors in the three-phase Vienna topology PFC mode of the embodiment of the present invention;

[0031] Figure 8 is the schematic diagram of the off circuit principles of the U-phase and V-phase power transistors in the three-phase Vienna topology PFC device of the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] To facilitate better understanding of the present invention by those skilled in the art, the present invention will be further described in detail below with reference to the drawings and specific embodiments. The following is merely exemplary and does not limit the protection scope of the present invention.

[0033] Combined with Figure 1The circuit schematic diagram of the embodiment of the present invention further details the single-phase interleaved and three-phase Vienna topology compatible input PFC device of the present invention.

[0034] A single-phase interleaved and three-phase Vienna topology compatible input PFC device described in the present invention includes a PFC unit and a control unit. The PFC unit includes 4 boost circuits and a filter circuit coupled to its output. The input end of the boost circuit is used to couple to an external AC power supply, and the output end of the filter circuit is used to couple to a load. The control unit includes an input voltage acquisition circuit, a drive circuit, a switching circuit, a digital signal processing circuit, an input current acquisition circuit, and an output voltage acquisition circuit.

[0035] Figure 2 It is the circuit schematic diagram of the first implementation manner of the embodiment of the present invention. When the external power supply input by the automotive wireless charging system is a single-phase AC power supply, manually combine the input power terminals 1 and 2 into one L terminal, and 3 and 4 into one N terminal. The single-phase alternating current is input from the L terminal and the N terminal respectively. Through the input voltage acquisition circuit, the input current acquisition circuit, and the output voltage acquisition circuit, the collected signals are transmitted to the DSP of the digital signal processing circuit for processing. The DSP disconnects the switch K1 through the switching circuit and keeps it in the disconnected state. The DSP adopts the pulse width modulation mode (PWM) method, and through the drive circuit, controls the on and off of the switching tubes Sup, Sun, Svp, Svn, Swp, Swn, Snp, and Snn. At this time, the device works in the single-phase interleaved PFC mode. The single-phase interleaved PFC is composed of two groups of single-phase PFC units. As Figure 3 shown, the first group of single-phase PFC units includes boost inductors Lu, Lw, diodes Dup, Dun, Dwp, Dwn, power tubes Sup, Sun, Swp, Swn, and filter capacitors C1, C2. As Figure 4 shown, the second group of single-phase PFC units includes boost inductors Lv, Ln, diodes Dvp, Dvn, Dnp, Dnn, switching tubes Svp, Svn, Snp, Snn, and filter capacitors C3, C4. R1 and R2 are load resistors. Among them, the drive circuit controls the switching frequency of the power tubes to be 50KHz, and the period is 20uS. One group of PFC devices is turned on every 10uS. The four power tubes of the first group of single-phase interleaved PFC and the four power tubes of the second group of single-phase interleaved PFC are turned on every 10uS, and conduct alternately.

[0036] As Figure 5As shown in Fig. a, when the L terminal is in the positive half-cycle of the alternating current and the N terminal is in the negative half-cycle of the alternating current, when the switching transistors Sup, Sun, Swn, and Swp are turned on, the alternating current flows in from the L terminal, passes through the inductor Lu to store energy, and then flows out from the N terminal through the internal diodes of the switching transistors Sup and Sun and the internal diodes of Swn and Swp and the inductor Lw. In another single-phase PFC unit, the energy stored in the capacitors C1 and C2 is released to the loads R1 and R2. As Figure 5 As shown in Fig. b, when the L terminal is still in the positive half-cycle of the alternating current and the switching transistors Sup, Sun, Swn, and Swp are turned off, the energy stored in the energy storage inductor Lw is released and flows out from the N terminal through the diode Dup, the energy storage capacitors C1 and C2, the diode Dwn, and the inductor Lw;

[0037] Figure 6 This is the circuit schematic diagram of the second implementation manner of the embodiment of the present invention. When the input of the electric vehicle wireless charging system is three-phase alternating current input, the device operates in the three-phase Vienna topology PFC mode. The U, V, and W terminals are respectively connected to the three live wires of the three-phase alternating current input, and the N-phase terminal is left floating; the digital signal processing circuit controls the single-pole double-throw switch K1 to close and keeps it closed. The first end of the switching switch K1 is connected to the negative electrode of C3 and the positive electrode of C4, the drain of the switching transistor Svn, the third end of the switching switch K1 is connected to the negative electrode of C1 and the positive electrode of C2, the drain of the switching transistor Sun, the drain of the switching transistor Swn, and the second end and the fourth end of the switching switch K1 are short-circuited.

[0038] The three-phase Vienna topology PFC device is composed of three groups of single-phase PFC circuits. Among them, the first group of PFC circuits includes the U-phase boost inductor Lu, the diodes Dup and Dun, the switching transistors Sup and Sun, and the capacitors C1 and C2. The second group of PFC circuits includes the V-phase boost inductor Lv, the diodes Dvp and Dvn, the switching transistors Svp and Svn, and the capacitors C3 and C4. The third group of PFC circuits includes the W-phase boost inductor Lw, the diodes Dwp and Dwn, the switching transistors Swp and Swn, and the capacitors C1 and C2. Among them, the power transistors Sup, Sun, Svp, Svn, Swp, Swn, Snp, and Snn are metal-oxide-semiconductor field-effect transistors, using NTHL065N65S3F; the diodes Dup, Dun, Dvp, Dvn, Dwp, Dwn, Dnp, and Dnn are semiconductor diodes, using STTH75S12, and the power transistor isolation drive of the drive circuit uses TLP5754D4-TP.

[0039] After the three-phase AC input power supply is connected to this device, the signals collected by the input voltage acquisition circuit, input current acquisition circuit, and output voltage acquisition circuit are transmitted to the DSP in the digital signal processing circuit for processing. The DSP adopts the pulse width modulation mode (PWM) and controls the conduction and cutoff of the switching tubes Sup, Sun, Svp, Svn, Swp, Swn, Snp, and Snn through the drive circuit. Among them, the voltage detection circuit detects the AC input voltage waveform and adopts the peak current detection mode. The input voltage differential acquisition chip of the input voltage acquisition circuit uses MC33274ADR2G, and the input current isolation detection chip of the input current acquisition circuit uses ACS730KLCTR-50AV-T. The DSP of the digital signal processing circuit uses TMS320F280049.

[0040] Taking the case where the U phase is positive and the V phase is negative as an example, the working current flow of the three-phase Vienna topology PFC device is described as follows. Figure 7 As shown, when the U terminal is in the positive half cycle of the AC, the AC current flows in from the U terminal, passes through the energy storage inductor Lu, and the switching tubes Sup, Sun, Svn, and Svp are turned on. The current flows from U -> Lu -> Sup -> Sun -> Svn -> Svp -> Lv -> N. Figure 8 As shown, when the switching tubes Sup, Sun, Svp, and Svn are turned off, the current flows from U -> Lu - Dup -> C1, C2 -> Dvn -> Lv -> N. Through the AC input voltage acquisition circuit, AC input current acquisition circuit, and output voltage acquisition circuit, the collected signals are transmitted to the digital signal processing (DSP) circuit. The DSP makes the switching switch K1 close through the switching control circuit. The DSP adopts the pulse width modulation mode (PWM) and controls the conduction and cutoff of the switching tubes Sup, Sun, Svp, Svn, Swp, Swn, Snp, and Snn through the switching tube drive circuit. When this device works in the three-phase Vienna topology PFC mode, the switching switch K1 must be in the closed state to work.

[0041] It should be noted that the models and specifications of the power tubes, diodes, integrated circuits required for voltage and current acquisition, and processors can be selected according to the actual situation. For example, the materials selected for the power tubes can be silicon carbide or gallium arsenide, and the specifications can use insulated gate bipolar transistors, etc.

[0042] As can be seen from the above embodiments, a single-phase interleaved and three-phase Vienna topology compatible input PFC device of the present invention not only controls the input connection mode of the input power terminals at the external power input end, but also controls the switching switch K1 through a digital signal processing circuit to achieve single-phase or three-phase AC compatible input and realize double protection. Secondly, by combining inductors, diodes, power transistors, and capacitor components, the cost of the device is effectively reduced and the volume is decreased. In addition, by adopting the three-phase Vienna topology PFC, the voltage stress on the power transistors is effectively reduced. By adopting the single-phase interleaved PFC, the average value of the input current is half of the total current, the switching and conduction losses of the power transistors are small, the cost is reduced, the product efficiency is improved, and the purpose of flexible and efficient wireless high-power charging for electric vehicles is met.

[0043] The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A single-phase interleaved and three-phase Vienna topology compatible input PFC device, characterized in that, it includes a PFC unit and a control unit; The PFC unit includes a boost circuit and a filter circuit coupled to its output. The input end of the boost circuit is used to be coupled to an external AC power supply, and the output end of the filter circuit is used to be coupled to a load; The control unit includes an input voltage acquisition circuit, a drive circuit, a switching circuit, and a digital signal processing circuit. The input end of the input voltage acquisition circuit is used to acquire the voltage at the input end of the boost circuit, and the output end is coupled to the digital signal processing circuit. The input ends of the drive circuit and the switching circuit are respectively coupled to the digital signal processing circuit, and the output ends are respectively coupled to the boost circuit; The digital signal processing circuit, based on the acquired voltage value of the input voltage acquisition circuit, controls the boost circuit to operate in the single-phase interleaved PFC mode when a single-phase AC power supply is input, and to operate in the three-phase Vienna topology PFC mode when a three-phase AC power supply is input through the switching circuit and the drive circuit; The boost circuit is set to 4 groups. Each group of boost circuits includes a boost inductor, a first diode and a second diode, a first power transistor and a second power transistor. The filter circuit includes filter capacitors C1 - C4; One end of the boost inductor is used to be coupled to an external AC power supply, and the other end is coupled to the positive electrode of the first diode, the negative electrode of the second diode, and the drain of the first power transistor. The negative electrode of the first diode, the positive electrodes of filter capacitors C1 and C3 are used to be coupled to the positive input end of the load. The positive electrode of the second diode, the negative electrodes of filter capacitors C2 and C4 are used to be coupled to the negative input end of the load; The source of the first power transistor is coupled to the source of the second power transistor, and the gates of the first power transistor and the second power transistor are coupled to the drive circuit; The drain of the second power transistor of the first group of boost circuits and the drain of the second power transistor of the third group of boost circuits are coupled as a first output end and coupled to the switching circuit. The drain of the second power transistor of the second group of boost circuits and the drain of the second power transistor of the fourth group of boost circuits are coupled as a second output end and coupled to the switching circuit; The switching circuit includes a switching switch K1 and a switching control circuit. The switching switch K1 includes a first switch and a second switch. The pin 1 of the first switch is coupled to the second output end of the boost circuit, the pin 2 of the first switch is coupled to the pin 2 of the second switch, and the pin 1 of the second switch is coupled to the first output end of the boost circuit; The input end of the switching control circuit is coupled to the digital signal processing circuit, and the output end is coupled to the first switch and the second switch. When a single-phase AC input is present, it controls the first switch and the second switch to be disconnected. When a three-phase AC input is present, it controls the switching switch K1 to be closed.

2. The PFC device according to claim 1, characterized in that: The switching switch K1 is a single-pole double-throw switch, a relay, or a semiconductor switch.

3. The PFC device according to claim 1, characterized in that: The control unit further includes an input current acquisition circuit. The input end of the input current acquisition circuit is coupled to the other ends of the boost inductors Lu, Lv, Lw, and Ln of the four boost circuits, and the output end is coupled to the digital signal processing circuit for acquiring the input current value after passing through the boost inductor.

4. The PFC device according to claim 1, wherein: The control unit further includes an output voltage acquisition circuit. The input end of the output voltage acquisition circuit is coupled to the output end of the filter circuit, and the output end is coupled to the digital signal processing circuit for acquiring the output voltage value.

5. The PFC device according to any one of claims 1-4, wherein: It further includes 4 input power terminals for external AC power input. For single-phase AC input, input power terminals 1 and 2 are combined to input AC L, and 3 and 4 are combined to input AC N; for three-phase AC input, input power terminals 1-3 respectively input U, V, and W of the three-phase AC, and terminal 4 is left floating.

6. The PFC device according to claim 5, wherein: The first power transistor and the second power transistor are metal oxide semiconductor field effect transistors, using NTHL065N65S3, and the first diode and the second diode are semiconductor diodes, using STTH75S12.

7. The PFC device according to claim 5, wherein: The drive circuit includes a power transistor isolation drive chip, using TLP5754D4-TP, and the digital signal processing circuit includes a DSP, using TMS320F280049.

8. The PFC device according to claim 5, wherein: The input voltage acquisition circuit includes an input voltage differential acquisition chip, using MC33274ADR2G; the input current acquisition circuit includes an input current isolation detection chip, using ACS730KLCTR-50AV-T.

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