10kV high-voltage multi-unit isolation auxiliary power supply

Abstract

The 10kV high-voltage multi-unit isolation auxiliary power supply comprises a first-stage circuit, a second-stage circuit, a third-stage circuit and a fourth-stage circuit, wherein the first-stage circuit, the second-stage circuit and the fourth-stage circuit are respectively composed of an NCP1396 control circuit, a current sampling circuit, a half-bridge LLC input side main circuit and a magnet ring transformer output rectification filter circuit; the half-bridge LLC input side main circuit is composed of a DC power supply DC1, an upper MOS tube Q3, a lower MOS tube Q4, a resonant capacitor C1, a resonant inductor L4 and a magnet ring transformer TR3. The current sampling circuit is composed of a current detection resistor R1 and an RC filter circuit. The NCP1396 control circuit is used for providing complementary and isolated driving control signals for grid electrodes of the upper MOS tube and the lower MOS tube, the input side of the magnetic ring transformer is connected with a turn of high-voltage 10kV insulated wire in series to serve as a primary winding, power supply of a high-voltage unit power source is met, meanwhile, the requirement for ultrahigh-voltage isolation is met, the requirements for voltage-withstanding insulation and power supply between units are met, and the service life of the high-voltage unit power source is prolonged. And the volume and the cost are well balanced.

Description

Technical Field

[0001] The utility model relates to an isolated auxiliary power supply, and more specifically, to a 10kV high-voltage multi-unit isolated auxiliary power supply, belonging to the technical field of switch power supplies. Background Art

[0002] Half-bridge LLC power supplies are widely used as auxiliary power supplies in various complex power electronic conversion systems to power board-level control systems and relay contactor systems. For high-voltage power electronic equipment above 10kV, when powering the control systems in each series unit or each phase unit, conventional AC-DC power supplies cannot meet the application due to low working isolation voltage, and it is difficult to directly take power from high-voltage 10kV and reduce the voltage. Conventional MOS component voltage levels cannot be achieved, or the cost of achieving them is extremely high.

[0003] For equipment above 10kV, there are many applications, and the control system in the unit requires a small auxiliary power supply, so the focus is on solving the need for high isolation voltage. For example, using a DC-DC power supply can efficiently convert energy, and the high isolation voltage requirement between the primary and secondary of the transformer can meet the system requirements. Summary of the invention

[0004] In order to overcome the disadvantages of the above technical problems, the utility model provides a 10kV high-voltage multi-unit isolated auxiliary power supply.

[0005] The utility model discloses a 10kV high-voltage multi-unit isolated auxiliary power supply, comprising a first-stage, a second-stage, a third-stage and a fourth-stage circuit, wherein the first-stage, the second-stage, the third-stage and the fourth-stage circuits are respectively an NCP1396 control circuit, a current sampling circuit, a half-bridge LLC input side main circuit and a magnetic ring transformer output rectifier filter circuit; the utility model is characterized in that: the half-bridge LLC input side main circuit is composed of a DC power supply DC1, an upper MOS tube Q3, a lower MOS tube Q4, a resonant capacitor C1, a resonant inductor L4 and a magnetic ring transformer TR3, and the current sampling circuit is The routing circuit is composed of a current-sensing resistor R1 and an RC filter circuit; the negative electrode of the DC power supply DC1 forms the power ground COM, the positive electrode is connected to the drain of the upper MOS tube Q3, the source of the upper MOS tube Q3 is connected to the drain of the lower MOS tube Q4 and one end of the resonant capacitor C1, the other end of the resonant capacitor C1 is connected to one end of the input side winding of the magnetic toroidal transformer TR3 through the resonant inductor L4, the other end of the primary winding of the magnetic toroidal transformer TR3 is connected to the power ground COM through the current-sensing resistor R1, and the source of the lower MOS tube Q4 is connected to the power ground COM;

[0006] The NCP1396 control circuit outputs a pulse control signal for controlling the upper MOS tube Q3 and the lower MOS tube Q4 to be alternately turned on and off. The voltage signal output by the current-sense resistor R1 is filtered by the RC filter circuit and input into the NCP1396 control circuit. The input side winding of the toroidal transformer TR3 is a single-turn winding formed by a 10kV high-voltage insulated wire. The output side winding of the toroidal transformer TR3 supplies power to the control board in the high-voltage unit through the toroidal transformer output rectifier filter circuit.

[0007] In the utility model of the 10kV high-voltage multi-unit isolated auxiliary power supply, the magnetic toroidal transformer TR3 is formed by connecting a plurality of magnetic toroidal transformers in parallel, and the output of one magnetic toroidal transformer supplies power to a control board in one high-voltage unit.

[0008] The utility model discloses a 10kV high-voltage multi-unit isolated auxiliary power supply, wherein the output rectification and filtering circuit of the magnetic toroidal transformer is composed of a full-wave rectifier bridge and a filter capacitor, the output side winding of the magnetic toroidal transformer TR3 is connected to the input end of the full-wave rectifier bridge, and the output of the full-wave rectifier bridge is filtered by the filter capacitor and then supplies power to the control board in the high-voltage unit.

[0009] The utility model discloses a 10kV high-voltage multi-unit isolated auxiliary power supply. The NCP1396 control circuit is composed of a half-bridge power chip NCP1396, a first triode push-pull circuit, a second triode push-pull circuit, a drive transformer TR1, a drive transformer TR2, a first voltage stabilizing circuit and a second voltage stabilizing circuit. The HO and HGND ports of the half-bridge power chip NCP1396 are connected to the input end of the first triode push-pull circuit, the LO and GND ports are connected to the input end of the second triode push-pull circuit, the FB port is connected to the output end of the RC filter circuit, the output of the first triode push-pull circuit is connected to the input side winding of the drive transformer TR1, and the output of the second triode push-pull circuit is connected to the input side winding of the drive transformer TR2.

[0010] One end of the output side winding of the driving transformer TR1 is connected to the gate of the upper MOS transistor Q3 via the first voltage stabilizing circuit, and the other end is connected to the source of the upper MOS transistor Q3; one end of the output side winding of the driving transformer TR2 is connected to the gate of the lower MOS transistor Q4 via the first voltage stabilizing circuit, and the other end is connected to the source of the lower MOS transistor Q4.

[0011] The beneficial effects of the utility model are as follows: the 10kV high-voltage multi-unit isolated auxiliary power supply of the utility model is provided with a first, second, third and fourth stage circuits consisting of an NCP1396 control circuit, a current sampling circuit, a half-bridge LLC input side main circuit and a magnetic toroidal transformer output rectifier filter circuit; the NCP1396 control circuit is used to provide complementary and isolated drive control signals to the upper and lower MOS tube gates of the half-bridge LLC main circuit; a turn of high-voltage 10kV insulated wire is connected in series on the input side of the magnetic toroidal transformer in the half-bridge LLC input side main circuit as a primary winding, which is used to realize the isolation, conversion and transmission of the primary energy of the magnetic toroidal transformer, realize the single-turn high isolation withstand voltage requirement, and convert the multi-channel high-voltage and low-current power supply on the output side through electromagnetic induction in a low-voltage and high-current manner, meet the high-voltage unit power supply, and realize the ultra-high voltage isolation requirement at the same time, have great application value in high-voltage power electronic equipment, solve the withstand voltage insulation and power supply requirements between units, and achieve a good balance between volume and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a circuit diagram of a 10kV high voltage multi-unit isolated auxiliary power supply of the utility model.

[0013] In the figure: 1 DC power supply DC1, 2 upper MOS tube Q3, 3 lower MOS tube Q4, 4 resonant capacitor C1, 5 resonant inductor L4, 6 magnetic ring transformer TR3, 7 current sensing resistor R1, 8 10kV high-voltage insulated wire, 9 RC filter circuit, 10 half-bridge power chip NCP1396, 11 first triode push-pull circuit, 12 second triode push-pull circuit, 13 drive transformer TR1, 14 drive transformer TR2, 15 first voltage stabilizing circuit, 16 second voltage stabilizing circuit, 17 full-wave rectifier bridge. DETAILED DESCRIPTION

[0014] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0015] like Figure 1As shown, a circuit diagram of a 10kV high-voltage multi-unit isolated auxiliary power supply of the utility model is given, which is composed of a first-level circuit, a second-level circuit, a third-level circuit and a fourth-level circuit. The first-level, second-level, third-level and fourth-level circuits are respectively NCP1396 control circuit, current sampling circuit, half-bridge LLC input side main circuit and magnetic ring transformer output rectifier filter circuit. The NCP1396 control circuit shown is composed of a half-bridge power chip NCP1396, a first triode push-pull circuit 11, a second triode push-pull circuit 12, a drive transformer TR1, a drive transformer TR2, a first voltage stabilizing circuit 15 and a second voltage stabilizing circuit 16. The half-bridge LLC input side main circuit is composed of a DC power supply DC1, an upper MOS tube Q3, a lower MOS tube Q4, a resonant capacitor C1, a resonant inductor L4 and a magnetic ring transformer TR3, and the current sampling circuit is composed of a current detection resistor R1 and an RC filter circuit 9; the magnetic ring transformer output rectifier filter circuit shown is composed of a full-wave rectifier bridge 17 and a filter capacitor.

[0016] The NCP1396 control circuit is used to provide complementary and isolated drive control signals to the upper and lower MOS gates in the half-bridge LLC main circuit. The half-bridge LLC input side main circuit is used to realize the isolation, conversion and transmission of the primary energy of the magnetic toroidal transformer, in which the common bus is used as the core point to achieve the single-turn high isolation withstand voltage requirement. The output rectifier and filter circuit of the magnetic toroidal transformer is used to transmit the input side alternating energy to the output stage through electromagnetic isolation, and transform it into a stable DC power supply after rectification and filtering. The current sampling circuit is used to collect the changing current signal of the half-bridge LLC input side main circuit in real time and transmit it to the control chip NCP1396 for current closed-loop regulation of the drive signal frequency.

[0017] The first-level circuit: NCP1396 control circuit. The chip NCP1396 outputs the upper bridge control signals HO and HGND. After being processed by the transistor push-pull circuit 1, the output signal is connected to the input side winding of the driving transformer TR1, and is transmitted to the output side winding of TR1 through electromagnetic isolation. The signal is processed by an external voltage stabilizing circuit and connected to the gate and source of the upper MOS tube Q3, providing an on / off control signal to the gate of Q3.

[0018] Similarly, the chip NCP1396 outputs the lower bridge control signal LO and GND, which are processed by the transistor push-pull circuit 2, and the output signal is connected to the input side winding of the driving transformer TR2, and transmitted to the output side winding of TR2 through electromagnetic isolation. The signal is processed by the external voltage stabilizing circuit and connected to the gate and source of the lower MOS tube Q4, providing the Q4 gate with an on / off control signal. The pin FB of the chip NCP1396 receives the current feedback signal from the main circuit to adjust the frequency of the output upper and lower bridge signals.

[0019] The second stage circuit: current sampling circuit, the negative bus of the main circuit is connected in series with the current sensing resistor R1, which converts the instantaneous current of the circuit into a voltage signal, which is transmitted to the FB pin of the chip MCP1396 for processing through the RC filtering circuit.

[0020] The third-stage circuit: the main circuit on the input side of the half-bridge LLC, the positive electrode of the voltage source DC1 is connected to the drain of the upper MOS tube Q3, the source of Q3 is connected to the drain of the lower MOS tube Q4, the connection point is connected to one end of the resonant capacitor C1, the other end of C1 is connected to the resonant inductor L4, the other end of L4 is a common bus, which is connected in series with multiple magnetic ring transformers in parallel, the terminal of the common bus is connected to the current sensing resistor R1, and the other end of R1 is connected to the power supply COM.

[0021] The fourth-level circuit: the output rectification and filtering circuit of the magnetic ring transformer. Taking a single magnetic ring as an example, the output winding of the magnetic ring is connected to the full-wave rectifier bridge, and then filtered by a capacitor to output a DC power supply to supply the subsequent unit load.

[0022] The DC power supply of the main circuit on the input side of the half-bridge LLC is controlled by the half-bridge control chip NCP1396. The duty cycle of the output signal is fixed at 50%, and the frequency is adjusted according to the actual load size. The common bus on the input side of the toroidal transformer in the main circuit on the input side of the half-bridge LLC is equivalent to the primary winding of the transformer, which is 1 turn. The output side can set more turns according to the actual voltage. Therefore, the input side is a single-turn low-voltage and high-current working mode. The feedback loop is mainly based on current regulation. The changing current signal is obtained through the current detection resistor and transmitted to the control chip NCP1396. The common bus is a single turn passing through multiple toroidal transformers. According to the primary and secondary isolation requirements, a 10kV high-voltage insulated wire can be used to form a loop, forming an extremely high isolation voltage level between the secondary winding of the toroidal transformer, thereby meeting the safety requirements of high-voltage inverters or SVG equipment.

[0023] It can be seen that the 10kV high-voltage multi-unit isolated auxiliary power supply of the utility model solves the withstand voltage insulation and power supply requirements between units, and the volume and cost are well balanced. Through the high-efficiency LLC half-bridge control method, the input side magnetic ring transformer is connected in series with a turn of high-voltage 10kV insulated wire as the primary winding, and is converted into multiple high-voltage and low-current power supplies on the output side through electromagnetic induction in a low-voltage and high-current manner, which meets the high-voltage unit power supply and realizes the ultra-high voltage isolation requirements at the same time, and has great application value in high-voltage power electronic equipment.

Claims

1. A 10kV high-voltage multi-unit isolated auxiliary power supply, comprising a first-stage, a second-stage, a third-stage and a fourth-stage circuit, wherein the first-stage, the second-stage, the third-stage and the fourth-stage circuits are respectively an NCP1396 control circuit, a current sampling circuit, a half-bridge LLC input side main circuit and a magnetic toroid transformer output rectifier filter circuit; characterized in that: The half-bridge LLC input side main circuit is composed of a DC power supply DC1 (1), an upper MOS tube Q3 (2), a lower MOS tube Q4 (3), a resonant capacitor C1 (4), a resonant inductor L4 (5) and a toroidal transformer TR3 (6); the current sampling circuit is composed of a current sensing resistor R1 (7) and an RC filter circuit (9); the negative electrode of the DC power supply DC1 forms a power ground COM, the positive electrode is connected to the drain of the upper MOS tube Q3, the source of the upper MOS tube Q3 is connected to the drain of the lower MOS tube Q4 and one end of the resonant capacitor C1, the other end of the resonant capacitor C1 is connected to one end of the input side winding of the toroidal transformer TR3 via the resonant inductor L4, the other end of the primary winding of the toroidal transformer TR3 is connected to the power ground COM via the current sensing resistor R1, and the source of the lower MOS tube Q4 is connected to the power ground COM; The NCP1396 control circuit outputs a pulse control signal for controlling the upper MOS tube Q3 and the lower MOS tube Q4 to be alternately turned on and off. The voltage signal output by the current sensing resistor R1 is filtered by the RC filter circuit and then input into the NCP1396 control circuit. The input side winding of the toroidal transformer TR3 is a single-turn winding formed by a 10 kV high-voltage insulated wire (8). The output side winding of the toroidal transformer TR3 supplies power to the control board in the high-voltage unit through the toroidal transformer output rectifier filter circuit.

2. The 10kV high voltage multi-unit isolated auxiliary power supply according to claim 1, characterized in that: The toroidal transformer TR3 (6) is formed by connecting a plurality of toroidal transformers in parallel, and the output of one toroidal transformer supplies power to a control board in a high-voltage unit.

3. The 10kV high voltage multi-unit isolated auxiliary power supply according to claim 1 or 2, characterized in that: The toroidal transformer output rectification and filtering circuit is composed of a full-wave rectifier bridge (17) and a filtering capacitor. The output side winding of the toroidal transformer TR3 is connected to the input end of the full-wave rectifier bridge. The output of the full-wave rectifier bridge is filtered by the filtering capacitor and then supplies power to the control board in the high-voltage unit.

4. The 10kV high voltage multi-unit isolated auxiliary power supply according to claim 1 or 2, characterized in that: The NCP1396 control circuit is composed of a half-bridge power chip NCP1396 (10), a first triode push-pull circuit (11), a second triode push-pull circuit (12), a drive transformer TR1 (13), a drive transformer TR2 (14), a first voltage stabilizing circuit (15) and a second voltage stabilizing circuit (16); the HO and HGND ports of the half-bridge power chip NCP1396 are connected to the input end of the first triode push-pull circuit, the LO and GND ports are connected to the input end of the second triode push-pull circuit, the FB port is connected to the output end of the RC filter circuit (9), the output of the first triode push-pull circuit is connected to the input side winding of the drive transformer TR1, and the output of the second triode push-pull circuit is connected to the input side winding of the drive transformer TR2; One end of the output side winding of the driving transformer TR1 is connected to the gate of the upper MOS transistor Q3 via the first voltage stabilizing circuit, and the other end is connected to the source of the upper MOS transistor Q3; one end of the output side winding of the driving transformer TR2 is connected to the gate of the lower MOS transistor Q4 via the first voltage stabilizing circuit, and the other end is connected to the source of the lower MOS transistor Q4.

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