A high-voltage large-capacitance charging power supply

Abstract

The present invention relates to the technical field of power supplies, and particularly to a high-voltage large-capacitance charging power supply, which includes an isolation transformer; the isolation transformer includes a three-phase input end, a first output winding, a second output winding, and a third output winding; a plurality of AC-DC circuits are respectively connected to the first output winding, the second output winding, and the third output winding; the output end of each AC-DC circuit is connected to a DC-DC circuit; the output ends of all the DC-DC circuits are connected in series to charge a high-voltage large capacitor; the DC-DC circuit includes a switching element, a diode D1, an inductor L1, a capacitor C138, a resistor R3, a first output port, and a second output port. The present invention uses a plurality of DC-DC circuits connected in series to charge a high-voltage large capacitor, thereby realizing the output of a high voltage. In addition, by setting the switching element, the diode D1, the inductor L1, the capacitor C138, and the resistor R3, a BUCK topology is formed as the main topology of the DC-DC circuit to realize constant current and constant current constant voltage control, so as to be able to charge the high-voltage large capacitor without damaging the power supply.

Description

Technical Field

[0001] The present invention relates to the technical field of power supplies, and particularly to a high-voltage large-capacitance charging power supply. Background Art

[0002] For charging a large-capacitance and high-voltage capacitor, if directly connected to a voltage source for charging, the instantaneous current is likely to be too large, which can easily cause damage to the power supply. To address this problem, there are mainly three methods in the current market:

[0003] The first one is as Figure 1 shown. The voltage rectified by a voltage regulator is applied to a capacitor through a scheme of adding a current-limiting resistor. However, this scheme has relatively high requirements for the resistor: the resistor power is large, the charging time is long, the power design of the resistor needs to be considered, the withstand voltage design of the resistor, and the thermal loss of the resistor is large, requiring a separate heat dissipation system or a large volume.

[0004] The second one is the same as the first scheme. A voltage regulator is added in front of the transformer at the front stage. Before each charging, the voltage regulator is adjusted to the maximum, and then adjusted upward slowly. This scheme solves the deficiencies existing in the first scheme, that is, the design requirements for the resistor are not so high. However, the disadvantages of this scheme are that this process requires a person to constantly monitor the voltage regulator for voltage adjustment, and in addition, a voltage detection device is needed to constantly measure the voltage, with low efficiency and difficult control of the voltage value.

[0005] The third one is to adopt a BOOST boost topology scheme. This method needs to consider the device withstand voltage problem. When charging at 10 kV, the device withstand voltage should be above 10 kV. It is difficult to select such a high device withstand voltage, and it is also relatively difficult to design the device series voltage equalization. Summary of the Invention

[0006] The purpose of the present invention is to provide a high-voltage large-capacitance charging power supply for the above deficiencies in the prior art.

[0007] The purpose of the present invention is achieved through the following technical solutions: A high-voltage large-capacitance charging power supply includes an isolation transformer; the isolation transformer includes three-phase input terminals, a first output winding, a second output winding, and a third output winding; several AC-DC circuits are respectively connected to the first output winding, the second output winding, and the third output winding; the output terminal of each AC-DC circuit is connected to a DC-DC circuit; the output terminals of all DC-DC circuits are connected in series to charge a high-voltage large capacitor.

[0008] The DC-DC circuit includes a switching device, a diode D1, an inductor L1, a capacitor C138, a resistor R3, a first output port, and a second output port; the switching end of the switching transistor Q2 is respectively connected to the output end of the AC-DC circuit and the negative electrode of the diode D1; the positive electrode of the diode D1 is grounded; the negative electrode of the diode D1 is connected to one end of the inductor L1; the other end of the inductor L1 is grounded through the capacitor C138 and the resistor R3 respectively; the other end of the inductor L1 is connected to the first output port; the second output port is grounded.

[0009] The present invention is further configured that the DC-DC circuit further includes a diode D3 and a diode D4; the diode D3 and the diode D4 are connected in parallel; the other end of the inductor L1 is connected to the positive electrode of the diode D3; the negative electrode of the diode D3 is connected to the first output port.

[0010] The present invention is further configured that the DC-DC circuit further includes a diode D5 and a diode D6; the diode D5 and the diode D6 are connected in parallel; the second output port is connected to the positive electrode of the diode D5; the negative electrode of the diode D5 is connected to the first output port.

[0011] The present invention is further configured that the switching device includes an IGBT transistor Q1 and an IGBT transistor Q2 connected in parallel with the IGBT transistor Q1; the drain of the IGBT transistor Q1 is connected to the output end of the AC-DC circuit; the source of the IGBT transistor Q1 is connected to the negative electrode of the diode D1; the DC-DC circuit further includes a diode D2 connected in parallel with the diode D1.

[0012] The present invention is further configured that the AC-DC circuit includes an EMI input module, a three-phase active PFC module, a DC-DC conversion module, and a DSP chip; the DSP chip is respectively used to control the three-phase active PFC module and the DC-DC conversion module;

[0013] The input end of the EMI input module is connected to the first output winding, the second output winding, or the third output winding; the output end of the EMI input module is connected to the input end of the three-phase active PFC module; the output end of the three-phase active PFC module is connected to the input end of the DC-DC conversion module; the output end of the DC-DC conversion module is connected to the input end of the DC-DC circuit.

[0014] The present invention is further configured that the DC-DC conversion module includes a transistor Q3, a transistor Q4, a transistor Q5, a transistor Q6, an inductor L3, an inductor L2, a transformer T2, a diode D11, a diode D12, a diode D13, and a diode D14;

[0015] The drain of the transistor Q3 and the drain of the transistor Q5 are respectively connected to the positive output terminal of the three-phase active PFC module; the source of the transistor Q4 and the source of the transistor Q6 are respectively connected to the negative output terminal of the three-phase active PFC module; the gates of the transistor Q3, the transistor Q4, the transistor Q5, and the transistor Q6 are respectively connected to the DSP chip; the source of the transistor Q3 is connected to the drain of the transistor Q4; the source of the transistor Q5 is connected to the drain of the transistor Q6; the source of the transistor Q3 is connected to one end of the primary side of the transformer T2 through the inductor L3; the source of the transistor Q5 is connected to the other end of the primary side of the transformer T2;

[0016] One end of the secondary side of the transformer T2 is respectively connected to the positive electrode of the diode D11 and the negative electrode of the diode D12; the other end of the secondary side of the transformer T2 is respectively connected to the positive electrode of the diode D13 and the negative electrode of the diode D14; the negative electrodes of the diode D11 and the diode D13 are respectively connected to the inductor L2; the positive electrodes of the diode D12 and the diode D14 are connected.

[0017] The present invention is further arranged such that the first output winding, the second output winding, and the third output winding are respectively connected to five AC-DC circuits; the output terminals of the fifteen DC-DC circuits are connected in series in sequence.

[0018] The present invention is further arranged such that a switch S1 is provided between the first output port of the first DC-DC circuit and one end of the high-voltage large capacitor; a switch S2 is provided between the second output port of the last DC-DC circuit and one end of the high-voltage large capacitor.

[0019] The beneficial effects of the present invention: The present invention uses multiple DC-DC circuits connected in series to charge the high-voltage large capacitor, thereby realizing the output of high voltage. In addition, by setting the switching element, the diode D1, the inductor L1, the capacitor C138, and the resistor R3, a BUCK topology is formed as the main topology of the DC-DC circuit to realize constant current and constant current constant voltage control, so as to be able to charge the high-voltage large capacitor without damaging the power supply. Description of the Drawings

[0020] The invention is further described with reference to the drawings, but the embodiments in the drawings do not constitute any limitation to the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the following drawings.

[0021] Figure 1 is the circuit schematic diagram of the prior art;

[0022] Figure 2 is the principle block diagram of the present invention;

[0023] Figure 3 It is the circuit schematic diagram of the AC-DC circuit of the present invention;

[0024] Figure 4 It is the circuit schematic diagram of the DC-DC circuit of the present invention;

[0025] Figure 5 It is the circuit block diagram of multiple series-connected DC-DC circuits of the present invention;

[0026] Wherein: 1. Isolation transformer; 11. First output winding; 12. Second output winding; 13. Third output winding; 2. High-voltage large-capacitance charging; 31. EMI input module; 32. Three-phase active PFC module; 33. DC-DC conversion module; 41. First output port; 42. Second output port. Specific embodiments

[0027] The present invention will be further described in conjunction with the following embodiments.

[0028] From Figures 2 to 5 it can be seen that a high-voltage large-capacitance charging 2 power supply described in this embodiment includes an isolation transformer 1; the isolation transformer 1 includes a three-phase input end, a first output winding 11, a second output winding 12, and a third output winding 13; the first output winding 11, the second output winding 12, and the third output winding 13 are respectively connected with a plurality of AC-DC circuits; the output end of each AC-DC circuit is connected with a DC-DC circuit; the output ends of all the DC-DC circuits are connected in series to charge the high-voltage large capacitance 2;

[0029] The DC-DC circuit includes a switching element, a diode D1, an inductor L1, a capacitor C138, a resistor R3, a first output port 41, and a second output port 42; the switching end of the switching transistor Q2 is respectively connected with the output end of the AC-DC circuit and the negative electrode of the diode D1; the positive electrode of the diode D1 is grounded; the negative electrode of the diode D1 is connected with one end of the inductor L1; the other end of the inductor L1 is respectively grounded through the capacitor C138 and the resistor R3; the other end of the inductor L1 is connected with the first output port 41; the second output port 42 is grounded.

[0030] Specifically, the high-voltage large capacitor charging 2 power supply described in this embodiment is used by the system to charge the high-voltage large capacitor. The voltage of the high-voltage large capacitor is charged from zero. If the high voltage of the power supply is directly connected to the high-voltage large capacitor, an instantaneous large current will be generated to damage the power supply or cause power supply protection. In order to achieve the high-voltage large capacitor charging 2 output voltage from 0 to a high voltage, the system uses multiple DC-DC circuits in series to charge the high-voltage large capacitor 2, thereby achieving high voltage output. In addition, this embodiment forms a BUCK topology as the main topology of the DC-DC circuit by setting a switch, a diode D1, an inductor L1, a capacitor C138 and a resistor R3 to achieve constant current, constant current and constant voltage control, so that the high-voltage large capacitor can be charged 2 without damaging the power supply.

[0031] The embodiment of the present invention describes a high-voltage large-capacitance charging power supply 2, wherein the DC-DC circuit further includes a diode D3 and a diode D4; the diode D3 and the diode D4 are connected in parallel; the other end of the inductor L1 is connected to the positive electrode of the diode D3; and the negative electrode of the diode D3 is connected to the first output port 41.

[0032] Specifically, this embodiment can effectively prevent current backflow by adding diodes D3 and D4 on the output side of the DC-DC circuit. Or when charging the external high-voltage large capacitor 2, the external high-voltage large capacitor has a very high voltage, and when connected to the main circuit, the internal capacitor of the power supply is charged to cause an instantaneous large current. After adding diodes D3 and D4, the singleness of the system current flow direction is guaranteed, thereby ensuring the system is more stable.

[0033] The embodiment of the present invention describes a high-voltage large-capacitance charging power supply, wherein the DC-DC circuit further includes a diode D5 and a diode D6; the diode D5 and the diode D6 are connected in parallel; the second output port 42 is connected to the positive electrode of the diode D5; and the negative electrode of the diode D5 is connected to the first output port 41.

[0034] Specifically, this embodiment connects diodes D5 and D6 in anti-parallel at the output end of the DC-DC circuit. Since the system is composed of multiple DC-DC circuits connected in series, the multiple DC-DC circuits will have the problem of asynchronous operation. If asynchronous operation occurs, the diodes D5 and D6 are not added. Description: When a DC-DC circuit of the system works and outputs to a DC-DC circuit that is not working at this time, the current flows through diodes D1, diodes D2, inductor L1, diodes D3 and diodes D4. Due to the existence of inductor L1, the instantaneous current has a large voltage. At this time, the capacitor at the output end of the DC-DC circuit has a large reverse pressure, and the capacitor will explode under the reverse pressure. If the system adds diodes D5 and D6, the system current flows through diodes D5 and D6, and there is no reverse pressure on the capacitor, which can ensure the safety of other modules of the system.

[0035] A high-voltage large-capacitance charging 2 power supply according to this embodiment, the switching device includes an IGBT transistor Q1 and an IGBT transistor Q2 connected in parallel with the IGBT transistor Q1; the drain of the IGBT transistor Q1 is connected to the output terminal of the AC-DC circuit; the source of the IGBT transistor Q1 is connected to the negative electrode of the diode D1; the DC-DC circuit further includes a diode D2 connected in parallel with the diode D1. Specifically, for the voltage withstand selection of the IGBT transistor Q1 and the IGBT transistor Q2, the IGBT transistors Q1 and Q in the BUCK have a voltage withstand of the bus voltage. Considering the switching noise of the system, the voltage withstand selection is 1.5-2 times the voltage withstand value, so the selection of a power device with 1200V can meet the system requirements. For the current selection of the IGBT transistor device: the peak current ripple of the inductor L1 is calculated at 20%, then the peak current of the inductor L1 is 36A. The IGBT transistor device current selects a device with an overcurrent capacity of 2-3 times, and a single transistor with 40A is selected. The system uses two 40A single transistors in parallel, and the device current is 80A. The IGBT device model is: HCKW40N120BH1 (1200V / 40A); the diode device model is: IDK40G120C5 (1200V / 40A).

[0036] A high-voltage large-capacitance charging 2 power supply according to this embodiment, the AC-DC circuit includes an EMI input module 31, a three-phase active PFC module 32, a DC-DC conversion module 33, and a DSP chip; the DSP chip is respectively used to control the three-phase active PFC module 32 and the DC-DC conversion module 33;

[0037] The input terminal of the EMI input module 31 is connected to the first output winding 11, the second output winding 12, or the third output winding 13; the output terminal of the EMI input module 31 is connected to the input terminal of the three-phase active PFC module 32; the output terminal of the three-phase active PFC module 32 is connected to the input terminal of the DC-DC conversion module 33; the output terminal of the DC-DC conversion module 33 is connected to the input terminal of the DC-DC circuit. A high-voltage large-capacitance charging 2 power supply according to this embodiment, the DC-DC conversion module 33 includes a transistor Q3, a transistor Q4, a transistor Q5, a transistor Q6, an inductor L3, an inductor L2, a transformer T2, a diode D11, a diode D12, a diode D13, and a diode D14;

[0038] The drain of the transistor Q3 and the drain of the transistor Q5 are respectively connected to the positive output terminal of the three-phase active PFC module 32; the source of the transistor Q4 and the source of the transistor Q6 are respectively connected to the negative output terminal of the three-phase active PFC module 32; the gates of the transistor Q3, the transistor Q4, the transistor Q5 and the transistor Q6 are respectively connected to the DSP chip; the source of the transistor Q3 is connected to the drain of the transistor Q4; the source of the transistor Q5 is connected to the drain of the transistor Q6; the source of the transistor Q3 is connected to one end of the primary side of the transformer T2 through the inductor L3; the source of the transistor Q5 is connected to the other end of the primary side of the transformer T2;

[0039] One end of the secondary side of the transformer T2 is respectively connected to the positive electrode of the diode D11 and the negative electrode of the diode D12; the other end of the secondary side of the transformer T2 is respectively connected to the positive electrode of the diode D13 and the negative electrode of the diode D14; the negative electrodes of the diode D11 and the diode D13 are respectively connected to the inductor L2; the positive electrodes of the diode D12 and the diode D14 are connected.

[0040] Specifically, the AC-DC circuit adopts an isolated power supply scheme, and uses the Vienna rectification + LLC topology scheme to achieve electrically isolated output. The isolation level meets the isolation level above 3 kV. The AC-DC circuit first uses VI ENNA rectification and then adds LLC to output a DC system with a power supply voltage of 750 V, and uses LLC to achieve electrical isolation of the power supply (the isolation level of the isolation transformer 1 meets the 3 kV isolation level).

[0041] The AC-DC circuit consists of an EMI input module 31, a three-phase active PFC module 32, a DC-DC conversion module 33 and a DSP chip circuit. The front-stage EMI input module 31 and the three-phase active PFC module 32 realize the rectification filtering of the AC input and the correction of the power factor to meet the EMC standard and obtain a total harmonic content of the current (THD i) less than 5%; the three-phase active PFC module 32 is controlled by the DSP chip. According to the AC input voltage, the input current is corrected to make it follow the AC input voltage, and a PWM wave is generated according to the result of the loop calculation to drive the main circuit and execute relevant protection measures; the latter-stage DC-DC conversion module 33 generates a PWM wave by the DSP chip to control the DC voltage output by the front-stage three-phase active PFC module 32. After passing through the high-frequency transformer T2 and then rectifying and filtering, the output current voltage is obtained, so as to convert the front-stage rectified voltage into a stable DC voltage required by the charging module, and thus provided to the DC-DC circuit.

[0042] A high-voltage large-capacitance charging 2 power supply according to this embodiment, the first output winding 11, the second output winding 12, and the third output winding 13 are respectively connected to five AC-DC circuits; the output ends of the fifteen DC-DC circuits are connected in series in sequence.

[0043] Specifically, for a high-voltage large capacitor with a capacitance of 10F and a capacitor voltage to be charged to 10kV, through the above settings in this embodiment, it can be designed to have an adjustable output voltage of 0 - 10kV, and can achieve functions such as constant-current charging and constant-current constant-voltage charging; first, the AC input is isolated by the isolation transformer 1 and then output through the first output winding 11, the second output winding 12, and the third output winding 13 to achieve isolation for each path (the isolation level meets the 10kV isolation level). The power of each output winding driving 15 AC-DC circuits is 20kW, and the output power of 1 AC-DC circuit driving 1 DC-DC circuit is also 20kW (the DC-DC circuit can achieve constant-current and constant-voltage control). The 15 DC-DC circuit power supplies are connected in series to charge the high-voltage large-capacitor cabinet. Each DC-DC circuit is independently controlled. The 15 DC-DC circuits connected in series can output 300kW. The output voltage of a single DDC-DC circuit is 700V. When 15 DC-DC circuits are connected in series, the maximum output voltage can reach 10.5kV, so as to meet the charging requirements for the capacitor voltage and the isolation requirements between multiple DDC-DC circuits.

[0044] Since the front stage of the system uses the isolation transformer 1 for isolation, the transformer has 1 input and 3 winding outputs, and the isolation level meets 10kV. Then, the isolation of the AC-DC circuit is used to satisfy the series connection of 5 groups of DC-DC circuits. In this way, the withstand voltage division of the 5 DC-DC circuits connected in series is only 3300V. The large isolation is achieved by using the isolation transformer 1, and the isolation level of the small voltage of the AC-DC circuit meets the series design requirements.

[0045] A high-voltage large-capacitance charging 2 power supply according to this embodiment, a switch S1 is provided between the first output port 41 of the first DC-DC circuit and one end of the high-voltage large capacitor; a switch S2 is provided between the second output port 42 of the last DC-DC circuit and one end of the high-voltage large capacitor.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A high-voltage large-capacitance charging power supply, characterized in that: It includes an isolation transformer (1); the isolation transformer (1) includes a three-phase input end, a first output winding (11), a second output winding (12), and a third output winding (13); several AC-DC circuits are respectively connected to the first output winding (11), the second output winding (12), and the third output winding (13); the output end of each AC-DC circuit is connected to a DC-DC circuit; the output ends of all the DC-DC circuits are connected in series to charge a high-voltage large capacitor (2). The DC-DC circuit includes a switching element, a diode D1, an inductor L1, a capacitor C138, a resistor R3, a first output port (41), and a second output port (42); the switching end of the switching element is respectively connected to the output end of the AC-DC circuit and the negative electrode of the diode D1; the positive electrode of the diode D1 is grounded; the negative electrode of the diode D1 is connected to one end of the inductor L1; the other end of the inductor L1 is grounded through the capacitor C138 and the resistor R3 respectively; the other end of the inductor L1 is connected to the first output port (41); the second output port (42) is grounded. The DC-DC circuit further includes a diode D3 and a diode D4; the diode D3 is connected in parallel with the diode D4; the other end of the inductor L1 is connected to the positive electrode of the diode D3; the negative electrode of the diode D3 is connected to the first output port (41). The DC-DC circuit further includes a diode D5 and a diode D6; the diode D5 is connected in parallel with the diode D6; the second output port (42) is connected to the positive electrode of the diode D5; the negative electrode of the diode D5 is connected to the first output port (41).

2. The high-voltage large-capacitance charging power supply according to claim 1, wherein: The switching element includes an IGBT tube Q1 and an IGBT tube Q2 connected in parallel with the IGBT tube Q1; the drain of the IGBT tube Q1 is connected to the output end of the AC-DC circuit; the source of the IGBT tube Q1 is connected to the negative electrode of the diode D1; the DC-DC circuit further includes a diode D2 connected in parallel with the diode D1.

3. The high-voltage large-capacitance charging power supply according to claim 1, wherein: The AC-DC circuit includes an EMI input module (31), a three-phase active PFC module (32), a DC-DC conversion module (33), and a DSP chip; the DSP chip is respectively used to control the three-phase active PFC module (32) and the DC-DC conversion module (33). The input end of the EMI input module (31) is connected to the first output winding (11), the second output winding (12), or the third output winding (13); the output end of the EMI input module (31) is connected to the input end of the three-phase active PFC module (32); the output end of the three-phase active PFC module (32) is connected to the input end of the DC-DC conversion module (33); the output end of the DC-DC conversion module (33) is connected to the input end of the DC-DC circuit.

4. The high-voltage large-capacitance charging power supply according to claim 3, wherein: The DC-DC conversion module (33) includes a transistor Q3, a transistor Q4, a transistor Q5, a transistor Q6, an inductor L3, an inductor L2, a transformer T2, a diode D11, a diode D12, a diode D13, and a diode D14. The drain of the transistor Q3 and the drain of the transistor Q5 are respectively connected to the positive output terminal of the three-phase active PFC module (32); the source of the transistor Q4 and the source of the transistor Q6 are respectively connected to the negative output terminal of the three-phase active PFC module (32); the gates of the transistor Q3, the transistor Q4, the transistor Q5, and the transistor Q6 are respectively connected to the DSP chip; the source of the transistor Q3 is connected to the drain of the transistor Q4; the source of the transistor Q5 is connected to the drain of the transistor Q6; the source of the transistor Q3 is connected to one end of the primary side of the transformer T2 through the inductor L3; the source of the transistor Q5 is connected to the other end of the primary side of the transformer T2; One end of the secondary side of the transformer T2 is respectively connected to the positive electrode of the diode D11 and the negative electrode of the diode D12; the other end of the secondary side of the transformer T2 is respectively connected to the positive electrode of the diode D13 and the negative electrode of the diode D14; the negative electrodes of the diode D11 and the diode D13 are respectively connected to the inductor L2; the positive electrodes of the diode D12 and the diode D14 are connected.

5. A high-voltage large-capacitance charging power supply according to claim 1, characterized in that: The first output winding (11), the second output winding (12), and the third output winding (13) are respectively connected to five AC-DC circuits; the output terminals of the fifteen DC-DC circuits are connected in series in sequence.

6. The high-voltage large-capacitance charging power supply according to claim 5, characterized in that: A switch S1 is provided between the first output port (41) of the first DC-DC circuit and one end of the high-voltage large capacitor; a switch S2 is provided between the second output port (42) of the last DC-DC circuit and one end of the high-voltage large capacitor.

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