A single-phase double-voltage pseudo totem-pole rectifier circuit for direct-current charging piles

Abstract

A single-phase double-voltage pseudo totem pole rectifier circuit for direct current charging pile, the circuit comprises an alternating current power supply U g , an inductor L1, an inductor L2, diodes D1-D6, switch tubes S1-S2, a capacitor C1, a capacitor C2, a capacitor C3, and a load R L ; the switch capacitor C2, the capacitor C3, the diode D5, and the inductor L3 are connected to constitute a double-voltage unit. The present application combines the advantages of single-phase pseudo totem pole circuit and double-voltage rectifier circuit, saves the loss of rectifier bridge by using totem pole bridgeless structure, and makes better use of space by double-inductor design, so that the volume of the whole circuit is reduced. And the double-voltage rectifier circuit is used to realize voltage multiplication. Compared with the traditional rectifier circuit, this circuit can effectively reduce the voltage stress of power devices, input current harmonic wave distortion and electromagnetic interference of the filter, thereby improving the overall performance and reliability of the system. At the same time, the double-voltage rectifier circuit can also be designed and adjusted according to the needs to adapt to different input and output voltage requirements.

Description

Technical Field

[0001] This invention relates to a single-phase rectifier circuit, and more particularly to a single-phase voltage doubler pseudo-totem pole rectifier circuit for DC charging piles. Background Technology

[0002] While traditional rectifier circuits are widely used in power conversion, they suffer from low efficiency and large output voltage fluctuations. DC charging piles, as core equipment for electric vehicle energy replenishment, require their front-end rectifier circuits to meet stringent requirements such as high power density, wide voltage adaptability, high efficiency, and low harmonics. Traditional solutions primarily use totem-pole rectifier circuits and cascaded boost topologies, but these have significant shortcomings in areas such as high voltage gain, component stress, and system reliability. Specific defects are as follows:

[0003] 1. Traditional totem-pole rectifier circuits reduce conduction losses due to their bridgeless structure, but their boost capability is limited by the Boost principle. For example, if the input voltage is 220V AC (peak 311V), and an output of 800V DC is required, a higher duty cycle is needed. A high duty cycle means that the voltage stress on the MOSFET when it is turned off is the DC load output voltage, and the reverse recovery current of the body diode of the totem-pole rectifier circuit will significantly increase the switching loss at high frequencies.

[0004] 2. To achieve high voltage output, traditional solutions often employ a rectifier circuit + DC / DC cascade structure, requiring an additional DC / DC stage. While introducing a DC / DC unit enables a wide output range, the combined efficiency of the two stages significantly decreases. Furthermore, the introduction of the DC / DC unit increases the circuit size; for example, an 800V output requires at least five diodes and one high-voltage capacitor, significantly increasing the PCB area.

[0005] 3. To improve power density, traditional solutions tend to favor high-frequency designs, such as above 150kHz. However, higher frequencies exacerbate switching losses and EMI issues. The charging and discharging losses of the MOSFET's output capacitor are directly proportional to its efficiency; as the switching frequency increases, so does the loss. Furthermore, high-frequency harmonics require larger common-mode inductors, leading to increased size of the charging station and making it impossible to meet the high power density requirements of the circuit. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a single-phase voltage doubler pseudo-totem pole rectifier circuit for DC charging piles. This rectifier circuit combines the advantages of pseudo-totem pole circuits and voltage doubler rectifier circuits. The bridgeless structure of the pseudo-totem pole circuit saves on rectifier bridge losses and can withstand higher power, meeting the needs of high-power applications. The circuit uses a voltage doubler rectifier circuit structure to achieve voltage multiplication. This novel rectifier circuit not only features high efficiency, stability, and flexibility, but also allows for design adjustments to adapt to different input and output voltage requirements. The technical solution adopted by this invention is as follows:

[0007] A single-phase voltage doubler pseudo-totem pole rectifier circuit for DC charging piles includes:

[0008] AC power supply U g Inductor L1, Inductor L2, Inductor L3, Diodes D1-D6, Switches S1-S2, Capacitors C1, C2, C3, Load R L ;

[0009] Power supply U g One end of each inductor is connected to one end of inductor L1 and one end of inductor L2 respectively, and they are all connected to node e;

[0010] Power supply U g The other end is connected to the anode of diode D1 and the cathode of diode D2, respectively, and they are connected together at node o;

[0011] The other end of inductor L1 is connected to the anode of diode D3 and the cathode of diode D4, respectively, and they are all connected to node a.

[0012] The other end of inductor L2 is connected to the source of switch S1 and the drain of switch S2, respectively, and is connected to node b.

[0013] The anode of diode D2 is connected to the anode of diode D4, the source of switch S2, the cathode of capacitor C2, the cathode of capacitor C1, and the load R. L The other end is connected, and both are connected to node d;

[0014] The anode of diode D5 is connected to the cathode of capacitor C3, the cathode of diode D1, the cathode of diode D3, and the drain of switching transistor S1, and they are all connected to node c.

[0015] The cathode of diode D5 is connected to the positive terminal of capacitor C2 and one end of inductor L3, and they are all connected to node g.

[0016] The anode of diode D6 is connected to the positive terminal of capacitor C3 and the other end of inductor L3, and they are connected together at node h.

[0017] The cathode of diode D6 is connected to the anode of capacitor C1, and the load R is connected to the cathode. L They are connected at one end and together connected to node p.

[0018] The capacitors C2 and C3, diode D5, and inductor L3 are connected to form a voltage multiplier unit.

[0019] In the rectifier circuit, all six diodes D1 to D6 can be replaced with MOSFETs, IGBTs, or IGCTs containing anti-parallel diodes, which can improve rectification efficiency, reduce power consumption and voltage loss, while also providing better controllability, reverse blocking capability, and heat dissipation performance.

[0020] This circuit includes four operating modes:

[0021] Mode 1: With switch S2 open and S1 open, current flows through inductor L1, diode D3, and then through inductor L2, converging at switch S1, before flowing through diode D5, inductor L3, diode D6, and load R. L Then, it returns to the power supply Ug through diode D2; at this time, inductors L1 and L2 supply power to the load R. L Charging; inductor L3 charges capacitor C3; capacitor C2 charges capacitor C1 through inductor L3 and diode D6; the current in inductor L1 decreases linearly, and the voltage U... ao =U bo =U1-U3, where U ao U represents the bridge arm voltage from node a to node o. bo U1 represents the voltage across the bridge arm from node b to node o, U2 represents the voltage across capacitor C1, and U3 represents the voltage across capacitor C3.

[0022] Mode 2: Switches S1 and S2 are turned on. Current flows through inductor L1, diode D3, switch S1, and then converges after passing through inductor L2. Finally, it flows through switch S2 and diode D2 back to power supply U. g At this time, the power supply U g Inductors L1 and L2 are charged; capacitor C3 charges capacitor C2 through inductor L3, and capacitor C1 charges the load R. L During charging, the current in inductor L1 increases linearly, and the voltage U... ao =U bo =0;

[0023] Mode 3: With switches S1 and S2 on, current flows through diode D1, then is shunted by switch S1, passing through inductor L2, and then through switch S2, diode D4, and inductor L1 before converging and returning to power supply U. g At this time, the power supply charges inductors L1 and L2; capacitor C3 charges capacitor C2 through inductor L3, and capacitor C1 charges the load R. LDuring charging, the current in inductor L2 increases linearly, and the voltage U... ao =U bo =0;

[0024] Mode 4: Switch S1 is open, S2 is open, and current flows through diode D1, diode D5, inductor L3, diode D6, and load R. L The current is then split, passing through switch S2 and inductor L2 respectively, and then through diode D4 and inductor L1 before converging and returning to the power supply Ug; at this time, inductors L1 and L2 supply power to the load R. L Charging; capacitor C2 charges capacitor C1 through inductor L3 and diode D6; the current in inductor L2 begins to decrease linearly, and the voltage U... ao =U bo =U3-U1.

[0025] In the six operating modes, the capacitor voltage U1 = U2 + U3 = U dc Where U2 represents the voltage across capacitor C2, U dc This indicates the output voltage of the DC load.

[0026] This invention discloses a single-phase voltage doubler pseudo-totem pole rectifier circuit for DC charging piles, with the following beneficial effects:

[0027] 1) The rectifier circuit of this invention has boost and rectification functions. The voltage and current stress on the switching transistor and some diodes is low. By combining with a voltage multiplier unit, this single-phase voltage multiplier pseudo-totem pole rectifier circuit can boost the input single-phase AC voltage by several times.

[0028] 2) This invention employs a quasi-Z-source network to construct a voltage multiplier unit structure, achieving voltage multiplication and possessing advantages such as high efficiency, stability, and flexibility. Furthermore, this single-phase voltage multiplier pseudo-totem pole rectifier circuit can be designed and adjusted as needed to adapt to different input and output voltage requirements.

[0029] 3) This rectifier circuit utilizes a totem-pole PFC bridgeless structure, saving on rectifier bridge losses. Furthermore, the dual-inductor design allows for better space utilization, reducing the overall circuit size. This novel rectifier circuit reduces system losses and costs, improves conversion efficiency, and extends the lifespan of the rectifier unit. Attached Figure Description

[0030] The present invention will be further described below with reference to the accompanying drawings and examples;

[0031] Figure 1 This is a schematic diagram of a single-phase voltage doubler pseudo-totem pole rectifier circuit for DC charging piles according to the present invention.

[0032] Figure 2This is a schematic diagram of the current path in the working mode 1 of a single-phase voltage doubler pseudo-totem pole rectifier circuit.

[0033] Figure 3 This is a schematic diagram of the current path in the second working mode of a single-phase voltage doubler pseudo-totem pole rectifier circuit.

[0034] Figure 4 This is a schematic diagram of the current path in the third working mode of a single-phase voltage doubler pseudo-totem pole rectifier circuit.

[0035] Figure 5 This is a schematic diagram of the current path in the fourth working mode of a single-phase voltage doubler pseudo-totem pole rectifier circuit.

[0036] Figure 6 This is a schematic diagram of the carrier modulation strategy for a single-phase voltage doubler pseudo-totem pole rectifier circuit.

[0037] Figure 7 The input voltage U of the single-phase voltage doubler pseudo-totem pole rectifier circuit g and current i g Waveform diagram.

[0038] Figure 8 The bridge arm voltage U of the single-phase voltage doubler pseudo-totem pole rectifier circuit ao U bo Waveform diagram.

[0039] Figure 9 The DC voltage U output by the single-phase voltage doubler pseudo-totem pole rectifier circuit dc Waveform diagram.

[0040] Figure 10 The bridge arm voltage U of a single-phase voltage doubler pseudo-totem pole rectifier circuit when the load is halved. ao U bo Waveform diagram.

[0041] Figure 11 The output DC voltage U of the single-phase voltage doubler pseudo-totem pole rectifier circuit when the load is halved dc Waveform diagram. Detailed Implementation

[0042] like Figure 1 As shown, a single-phase voltage doubler pseudo-totem pole rectifier circuit for DC charging piles includes:

[0043] AC power supply U g Inductor L1, Inductor L2, Inductor L3, Diodes D1-D6, Switches S1-S2, Capacitors C1, C2, C3, Load R L ;

[0044] Power supply U g One end of each inductor is connected to one end of inductor L1 and one end of inductor L2 respectively, and they are all connected to node e;

[0045] Power supply U g The other end is connected to the anode of diode D1 and the cathode of diode D2, respectively, and they are connected together at node o;

[0046] The other end of inductor L1 is connected to the anode of diode D3 and the cathode of diode D4, respectively, and they are all connected to node a.

[0047] The other end of inductor L2 is connected to the source of switch S1 and the drain of switch S2, respectively, and is connected to node b.

[0048] The anode of diode D2 is connected to the anode of diode D4, the source of switch S2, the cathode of capacitor C2, the cathode of capacitor C1, and the load R. L The other end is connected, and both are connected to node d;

[0049] The anode of diode D5 is connected to the cathode of capacitor C3, the cathode of diode D1, the cathode of diode D3, and the drain of switching transistor S1, and they are all connected to node c.

[0050] The cathode of diode D5 is connected to the positive terminal of capacitor C2 and one end of inductor L3, and they are all connected to node g.

[0051] The anode of diode D6 is connected to the positive terminal of capacitor C3 and the other end of inductor L3, and they are connected together at node h.

[0052] The cathode of diode D6 is connected to the anode of capacitor C1, and the load R is connected to the cathode. L They are connected at one end and together connected to node p.

[0053] The capacitors C2 and C3, diode D5, and inductor L3 are connected to form a voltage multiplier unit.

[0054] The following describes the specific working principle of the rectifier circuit of this invention, a single-phase voltage doubler pseudo-totem pole rectifier circuit for DC charging piles. The single-phase voltage doubler pseudo-totem pole rectifier circuit has four operating modes, and the specific analysis process is as follows:

[0055] Figure 2 The current path diagram for Mode 1 is as follows: Switch S2 is open, S1 is open, and the current flows through inductor L1, diode D3, and then through inductor L2, before converging at switch S1. The current then flows through diode D5, inductor L3, diode D6, and finally the load R. L Then, it returns to the power supply Ug through diode D2; at this time, inductors L1 and L2 supply power to the load R. L Charging; inductor L3 charges capacitor C3; capacitor C2 charges capacitor C1 through inductor L3 and diode D6; the current in inductor L1 decreases linearly, and the voltage U... ao=U bo =U1-U3;

[0056] Figure 3 The current path diagram for Mode 2 is as follows: With switches S1 and S2 on, the current flows through inductor L1, diode D3, switch S1, and then converges after passing through inductor L2. Finally, it flows through switch S2 and diode D2 back to the power supply U. g At this time, the power supply U g Inductors L1 and L2 are charged; capacitor C3 charges capacitor C2 through inductor L3, and capacitor C1 charges the load R. L During charging, the current in inductor L1 increases linearly, and the voltage U... ab =0;

[0057] Figure 4 The current path diagram for mode 3 is as follows: Switches S1 and S2 are turned on, and the current flows through diode D1. After switching S1, the current is shunted and flows through inductor L2, and then through switch S2, diode D4, and inductor L1 before converging and returning to power supply U. g At this time, the power supply charges inductors L1 and L2; capacitor C3 charges capacitor C2 through inductor L3, and capacitor C1 charges the load R. L During charging, the current in inductor L2 increases linearly, and the voltage U... ab =0;

[0058] Figure 5 This is a schematic diagram of the current path in mode 4: Switch S1 is open, S2 is open, and current flows through diode D1, diode D5, inductor L3, diode D6, and load R. L The current is then split, passing through switch S2 and inductor L2 respectively, and then through diode D4 and inductor L1 before converging and returning to the power supply Ug; at this time, inductors L1 and L2 supply power to the load R. L Charging; capacitor C2 charges capacitor C1 through inductor L3 and diode D6; the current in inductor L2 begins to decrease linearly, and the voltage U... ao =U bo =U3-U1;

[0059] Table 1 shows the correspondence between the pulse distribution method of the rectifier circuit switching transistor and the operating states of the DC side inductor and capacitor. The on and off states of the switching transistor are represented by "1" and "0" respectively.

[0060] Table 1. Correspondence between pulse distribution method of rectifier circuit switching transistor, and operating state of DC side inductor and capacitor.

[0061]

[0062] Figure 6 This is a schematic diagram of the multi-carrier modulation strategy of the pseudo-totem pole rectifier circuit in this invention. (See diagram below.) Figure 10As shown, the modulation signal U ref It is a sine wave, which is related to the triangular carrier signal V. i Compare (i = 1, 2), when U ref >V i When the corresponding operating mode is active, the switching transistor is turned on; otherwise, it is turned off, thereby modulating the output voltage U to approximately sinusoidal. ao U bo The waveform, based on the four operating modes of the pseudo-totem pole rectifier circuit, can convert the voltage U... ao U bo The voltage is divided into two intervals: interval one (0, U1-U3) and interval two (U3-U1, 0), with voltage U... ao U bo There are three voltage levels: 0, U1-U3, and U1-U3.

[0063] To verify that the single-phase voltage doubler pseudo-totem pole rectifier circuit for DC charging piles of this invention can achieve voltage doubler function, an experiment was conducted under a dual-loop control strategy. The experimental parameters were as follows: input voltage RMS value 220V, operating frequency 50Hz, inductors L1 and L2 2.5mH, inductor L3 2.5mH, capacitor C1 3500uF, capacitor C2 250uF, capacitor C3 160uF, switching frequency 20kHz, and load 80Ω.

[0064] Figure 7 The input voltage U of the single-phase voltage doubler pseudo-totem pole rectifier circuit g and current i g The waveform diagram shows that this invention, by controlling the on and off states of the switching converter, 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. Figure 7 As shown in the waveform, the voltage and current are in phase, which means that the power factor correction function is achieved.

[0065] Figure 8 For the pseudo-totem pole rectifier circuit voltage U ab Waveform diagram, such as Figure 8 As shown, the pseudo-totem pole rectifier circuit of this invention distributes pulses to the switching transistors in each mode and employs a multi-carrier modulation strategy to output a two-level voltage waveform U. ao U bo The experimental results are consistent with the theoretical analysis.

[0066] Figure 9 The DC voltage U output by the single-phase voltage doubler pseudo-totem pole rectifier circuit dc The waveform diagram shows that this invention designs a single-phase voltage doubler pseudo-totem pole rectifier circuit with an input of 220V and an output of 800V, consisting of... Figure 9 As can be seen from the waveform, voltage U has been achieved. dc Doubled.

[0067] Figure 10 The bridge arm voltage U when the load of the pseudo-totem pole rectifier circuit is halved ao U bo The waveform diagram shows that when the load abruptly decreases from 80Ω to 40Ω in 0.35s and then recovers to 40Ω in 0.4s, the voltage U can be observed from the waveform. ao U bo No significant fluctuations.

[0068] Figure 11 The output DC voltage U of the single-phase voltage doubler pseudo-totem pole rectifier circuit when the load is halved dc Waveform diagram, output DC voltage U dc The waveform undergoes slight adjustments between 0.35s and 0.4s and quickly returns to a stable state, indicating that the single-phase voltage doubler rectifier circuit has strong dynamic adjustment capability and good anti-disturbance performance.

[0069] This invention discloses a single-phase voltage doubler pseudo-totem pole rectifier circuit for DC charging piles. This single-phase voltage doubler pseudo-totem pole rectifier circuit enables the rectifier circuit to have low voltage stress on the switch, thereby reducing cost and switching losses. Compared with traditional boost converters, which cannot provide high voltage gain due to parasitic resistance in the circuit, this circuit adopts a pseudo-totem pole PFC bridgeless structure, saving rectifier bridge losses and effectively improving power conversion efficiency. Furthermore, the dual-inductor design can better utilize space, reducing the overall circuit size.

Claims

1. A single-phase voltage doubler pseudo-totem pole rectifier circuit for DC charging piles, characterized in that... include: AC power supply U g Inductor L1, Inductor L2, Inductor L3, Diodes D1~D6, Switching transistor S 1~ S 2. Capacitor C1, Capacitor C2, Capacitor C3, Load R L ; Power supply U g One end of the inductor is connected to one end of inductor L1 and one end of inductor L2 respectively, and they are all connected to the node. e ; power supply U g The other end is connected to the anode of diode D1 and the cathode of diode D2, respectively, and together they are connected to the node. o ; The other end of inductor L1 is connected to the anode of diode D3 and the cathode of diode D4, respectively, and they are all connected to the node. a ; The other end of inductor L2 is connected to the source of switch S1 and the drain of switch S2, respectively, and together they are connected to the node. b ; The anode of diode D2 is connected to the anode of diode D4, the source of switch S2, the cathode of capacitor C2, the cathode of capacitor C1, and the load R. L The other end is connected, and they are both connected to the node. d ; The anode of diode D5 is connected to the cathode of capacitor C3, the cathode of diode D1, the cathode of diode D3, and the drain of switching transistor S1, all connected at the node. c ; The cathode of diode D5 is connected to the anode of capacitor C2 and one end of inductor L3, and they are all connected to the node. g ; The anode of diode D6 is connected to the positive terminal of capacitor C3 and the other end of inductor L3, and they are all connected to the node. h ; The cathode of diode D6 is connected to the anode of capacitor C1, and the load R is connected to the cathode. L One end is connected, and they are both connected to the node. p ; This rectifier circuit includes four operating modes: Mode 1: With switch S2 open and S1 open, current flows through inductor L1, diode D3, and then through inductor L2, converging at switch S1, before flowing through diode D5, inductor L3, diode D6, and load R. L Then, it returns to the power supply Ug through diode D2; at this time, inductors L1 and L2 supply power to the load R. L Charging; inductor L3 charges capacitor C3; capacitor C2 charges capacitor C1 through inductor L3 and diode D6; the current in inductor L1 decreases linearly, and the voltage U... ao =U bo =U1-U3, where U ao U represents the bridge arm voltage from node a to node o. bo U1 represents the voltage across the bridge arm from node b to node o, U2 represents the voltage across capacitor C1, and U3 represents the voltage across capacitor C3. Mode 2: Switches S1 and S2 are turned on. Current flows through inductor L1, diode D3, switch S1, and then converges after passing through inductor L2. Finally, it flows through switch S2 and diode D2 back to power supply U. g At this time, the power supply U g Inductors L1 and L2 are charged; capacitor C3 charges capacitor C2 through inductor L3, and capacitor C1 charges the load R. L During charging, the current in inductor L1 increases linearly, and the voltage U... ao =U bo =0; Mode 3: With switches S1 and S2 on, current flows through diode D1, then is shunted by switch S1, passing through inductor L2, and then through switch S2, diode D4, and inductor L1 before converging and returning to power supply U. g At this time, the power supply charges inductors L1 and L2; capacitor C3 charges capacitor C2 through inductor L3, and capacitor C1 charges the load R. L During charging, the current in inductor L2 increases linearly, and the voltage U... ao =U bo =0; Mode 4: Switch S1 is open, S2 is open, and current flows through diode D1, diode D5, inductor L3, diode D6, and load R. L The current is then split, passing through switch S2 and inductor L2 respectively, and then through diode D4 and inductor L1 before converging and returning to the power supply Ug; at this time, inductors L1 and L2 supply power to the load R. L Charging; capacitor C2 charges capacitor C1 through inductor L3 and diode D6; the current in inductor L2 begins to decrease linearly, and the voltage U... ao =U bo =U3-U1.

2. The single-phase voltage doubler pseudo-totem pole rectifier circuit for DC charging piles according to claim 1, characterized in that: The capacitor C 2. Capacitor C 3. Diode D5, Inductor L 3 connections form a voltage multiplier unit.

3. The single-phase voltage doubler pseudo-totem pole rectifier circuit for DC charging piles according to claim 1, characterized in that: In the rectifier circuit, all six diodes D1 to D6 can be replaced with MOSFETs, IGBTs, or IGCTs containing anti-parallel diodes.

4. The single-phase voltage doubler pseudo-totem pole rectifier circuit for DC charging piles according to claim 1, characterized in that: In the six operating modes, the capacitor voltage U1 = U2 + U3 = U dc Where U2 represents the voltage across capacitor C2, U dc This indicates the output voltage of the DC load.

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