A power supply circuit for charging an energy storage capacitor

Abstract

The utility model discloses a kind of energy storage capacitor charging power supply circuit, including input protection module, LLC boost module, first step-down power supply module, adjustable step-down charging module and MCU control module;The MCU control module is electrically connected with LLC boost module, first step-down power supply module, adjustable step-down charging module respectively, for collecting charging voltage, current and environmental temperature data, control charging process to meet preset charging time length requirement, and shut off charging output when energy storage capacitor is used for circuit breaker opening and closing operation.This utility model optimizes boost and step-down circuit design, realizes 15S inside completion energy storage capacitor charging, meets circuit breaker fast action demand, adapts different specifications power distribution cabinet circuit breaker's energy storage capacitor, reduces user replacement cost, reduces mains loss, meets energy efficiency standard.

Description

Technical Field

[0001] This utility model relates to the field of charging power supply control, specifically to a charging power supply circuit for an energy storage capacitor. Background Technology

[0002] The opening and closing operations of circuit breakers in distribution cabinets are usually achieved by the electricity stored in the internal energy storage capacitors. Charging the energy storage capacitors requires a special charger that can output 500V voltage as needed, with a charging time of 15 seconds. During the opening and closing operations, the charger output needs to be turned off to ensure that the thyristors are turned off. Therefore, an energy storage capacitor charging power supply circuit is required. Summary of the Invention

[0003] The purpose of this invention is to provide a power supply circuit for charging energy storage capacitors.

[0004] This utility model includes an input protection module, an LLC boost module, a first buck power supply module, an adjustable buck charging module, and an MCU control module; The input protection module is used to connect to AC220V mains power and realize overcurrent, overvoltage and EMC filtering protection; The LLC boost module is electrically connected to the input protection module. After rectifying and filtering the AC220V, it is converted into a stable DC500V voltage through LLC resonance and PFC power factor correction. The first step-down power supply module is electrically connected to the output terminal of the LLC boost module, which steps down the DC500V to 12V DC voltage to provide working power for the back-end control circuit. The adjustable step-down charging module is electrically connected to the output terminal of the LLC boost module, and can step down DC500V to an adjustable DC voltage of 300-500V to provide charging voltage for the energy storage capacitor; The MCU control module is electrically connected to the LLC boost module, the first buck power supply module, and the adjustable buck charging module, respectively. It is used to collect charging voltage, current and ambient temperature data, control the charging process to meet the preset charging time requirements, and shut off the charging output when the energy storage capacitor is used for circuit breaker opening and closing operations.

[0005] Furthermore, the input protection module includes a fuse F1, a varistor RV1, a first common-mode inductor LF1, Y capacitors CY1-CY2, and a first relay SW1. The fuse F1 is used for overcurrent protection, the varistor RV1 is used to absorb abnormal voltage pulses, and LF1 and CY1-CY2 work together to filter out common-mode interference to meet EMC requirements. The SW1 is a normally closed relay that disconnects when the downstream circuit is abnormal, cutting off the mains power input. The input protection module also includes a thermistor RT1. When the relay SW1 is open, the downstream circuit is powered through RT1. Under abnormal operating conditions, RT1 heats up and limits the current.

[0006] Furthermore, the LLC boost module includes a rectifier bridge DB1, a high-voltage electrolytic capacitor CE1, a combined controller U1, a resonant transformer T1, driving MOSFETs Q5-Q6, an auxiliary winding N4, and an output feedback unit; The output feedback unit consists of the seventh capacitor C7, the ninth capacitor C9, the thirteenth capacitor C13, PC1, R11, the twentieth resistor R20, the twenty-first resistor R21, the twenty-eighth resistor R28, the twenty-ninth resistor R29, the thirty-second resistor R32, the thirty-third resistor R33, U2, and RW1. It is connected to the feedback pin of the combined controller U1 to stabilize the output voltage of the LLC boost module at DC500V.

[0007] Furthermore, the first step-down power supply module is a BUCK step-down circuit, including a DC-DC isolation chip U3, a first energy storage inductor L1, a tenth freewheeling diode D10, a thirty-sixth voltage feedback sampling resistor R36 and a thirty-seventh voltage feedback sampling resistor R37, and a filter capacitor bank.

[0008] Furthermore, the adjustable buck charging module includes an overcurrent protection unit, a gate drive unit, a power conversion unit, a voltage acquisition unit, a current protection unit, and a PWM control unit.

[0009] Furthermore, the MCU control module includes a power conversion unit, a data acquisition unit, an interface unit, and an indicator unit; the power conversion unit includes an LDO chip U4.

[0010] The beneficial effects of this utility model are as follows: This invention optimizes the design of the boost and buck circuits, enabling the energy storage capacitor to be charged within 15 seconds, meeting the requirements for rapid operation of the circuit breaker, adapting to the energy storage capacitors of different specifications of distribution cabinet circuit breakers, reducing user replacement costs, reducing mains power loss, and meeting energy efficiency standards. Attached Figure Description

[0011] Figure 1 This is the circuit schematic diagram of this utility model; Detailed Implementation

[0012] The present invention will be further described below with reference to the embodiments. The embodiments of the present invention include, but are not limited to, the following embodiments.

[0013] like Figure 1 As shown, this utility model includes an input protection module, an LLC boost module, a first buck power supply module, an adjustable buck charging module, and an MCU control module; The input protection module is used to connect to AC220V mains power and realize overcurrent, overvoltage and EMC filtering protection; The LLC boost module is electrically connected to the input protection module. After rectifying and filtering the AC220V, it is converted into a stable DC500V voltage through LLC resonance and PFC power factor correction. The first step-down power supply module is electrically connected to the output terminal of the LLC boost module, which steps down the DC500V to 12V DC voltage to provide working power for the back-end control circuit. The adjustable step-down charging module is electrically connected to the output terminal of the LLC boost module, and can step down DC500V to an adjustable DC voltage of 300-500V to provide charging voltage for the energy storage capacitor; The MCU control module is electrically connected to the LLC boost module, the first buck power supply module, and the adjustable buck charging module, respectively. It is used to collect charging voltage, current and ambient temperature data, control the charging process to meet the preset charging time requirements, and shut off the charging output when the energy storage capacitor is used for circuit breaker opening and closing operations.

[0014] In the LLC boost circuit, the LLC boost circuit converts AC220V to DC500V. CN1 is the power input terminal, used to connect external L, N, and PE. F1 is a fuse for overcurrent protection. RV1 is a varistor used to absorb abnormal voltage pulses. LF1 is a common-mode inductor used to attract common-mode signals to improve EMC. CY1 and CY2 are Y capacitors connected between L, N, and PE ground to meet safety requirements. SW1 is a relay that cuts off the power input when the downstream is abnormal. RT1 is a thermistor; when the relay is open, it is powered through RT1, and when abnormal, the thermistor heats up to limit the current. CX2 is an X capacitor that filters differential-mode signals. LF2 and LF3 are common-mode filters to improve EMC. CX1 is an X capacitor that filters differential-mode signals to improve EMI. DB1 is a rectifier bridge that rectifies AC into pulsating DC. CE1 is a high-voltage electrolytic capacitor that filters non-pulsating DC voltage into a stable DC voltage. U1 is a high-efficiency resonant power supply LLC plus PFC combined controller.

[0015] In this embodiment, the input protection module includes a fuse F1, a varistor RV1, a first common-mode inductor LF1, Y capacitors CY1-CY2, and a first relay SW1. The fuse F1 is used for overcurrent protection, the varistor RV1 is used to absorb abnormal voltage pulses, and LF1 and CY1-CY2 work together to filter out common-mode interference to meet EMC requirements. The SW1 is a normally closed relay that disconnects when the downstream circuit is abnormal, cutting off the mains power input. The input protection module also includes a thermistor RT1. When the relay SW1 is open, the downstream circuit is powered through RT1. Under abnormal operating conditions, RT1 heats up and limits the current.

[0016] Furthermore, the LLC boost module includes a rectifier bridge DB1, a high-voltage electrolytic capacitor CE1, a combined controller U1, a resonant transformer T1, driving MOSFETs Q5-Q6, an auxiliary winding N4, and an output feedback unit; The output feedback unit consists of the seventh capacitor C7, the ninth capacitor C9, the thirteenth capacitor C13, PC1, R11, the twentieth resistor R20, the twenty-first resistor R21, the twenty-eighth resistor R28, the twenty-ninth resistor R29, the thirty-second resistor R32, the thirty-third resistor R33, U2, and RW1. It is connected to the feedback pin of the combined controller U1 to stabilize the output voltage of the LLC boost module at DC500V.

[0017] In this embodiment, the first step-down power supply module is a BUCK step-down circuit, including a DC-DC isolation chip U3, a first energy storage inductor L1, a tenth freewheeling diode D10, a thirty-sixth voltage feedback sampling resistor R36 and a thirty-seventh voltage feedback sampling resistor R37, and a filter capacitor bank.

[0018] In this embodiment, the adjustable buck charging module includes an overcurrent protection unit, a gate drive unit, a power conversion unit, a voltage acquisition unit, a current protection unit, and a PWM control unit.

[0019] The overcurrent protection unit includes PTC1-PTC2 (600V 0.5A) for overcurrent self-recovery protection; the gate drive unit includes gate drive chip U5 (i6801B-DSWFR) and isolation power supply U6 (12V to 12V), with U6 providing isolation drive voltage for U5; the power conversion unit includes MOSFET Q7 (STP8N120K5), energy storage inductor L2 (1mH / 2A), silicon carbide diode D15 (SICRF101200), and freewheeling diode D14 (SIEFI120), with U5 controlling the on / off state of Q7 to achieve voltage reduction; the voltage acquisition unit consists of R47-R49 and C35, acquiring the output voltage and feeding it back to the MCU control module; the current protection unit includes comparator U8, operational amplifier U9, and current sampling resistor RL1, with U8 limiting the charging current through hardware control, and U9 amplifying the current signal acquired by RL1 and feeding it back to the MCU. Control module; The PWM control unit receives the PWM signal output by the MCU and adjusts the duty cycle of Q7 to achieve an adjustable output voltage of 300-500V.

[0020] In this embodiment, the MCU control module includes a power conversion unit, a data acquisition unit, an interface unit, and an indicator unit; the power conversion unit includes an LDO chip U4.

[0021] Chip U4 converts the 12V output from the first step-down power supply module to 3.3V to power the MCU (MU1, STM32 series), and works with C24 and C32-C34 filter capacitors to suppress power supply interference. The data acquisition unit includes an NTC thermistor TR3 (in conjunction with R59 and C51), voltage acquisition resistors R38-R40 (acquiring DC 500V voltage), and current sampling resistor RL1 (in conjunction with U9), which respectively acquire ambient temperature, input voltage, and charging current. The interface unit includes a programming port H1 and a display interface JP1. The indicator unit includes LED1 to indicate the power supply operating status. The MCU control module also includes a series resistor R43, which connects the power supply GND and the control GND to eliminate ground loop interference and limit fault current.

[0022] R5 R6 R7 D1 RT2 C1 C2 form the AC power detection circuit, which is connected to pin 1 of U1. HVCC supplies power to the HV terminal of U1 through R8, which is connected to pin 8. R12 R13 R14 R15 C5 form the voltage divider circuit. Connected to pin 2 of U1, used to detect the boost voltage. T1 is a resonant transformer, boosting 300V to 500V. Q5 and Q6 are the driving MOSFETs for the LLC resonant circuit. R17, R18, R22, R23, R26, R27, D5, D6, Q3, and Q4 form the MOSFET driving circuit, connected to pins 6 and 9 of U1. C11, C12, C14, C15, C16, CP1, R24, R30, R31, and R34 constitute the LLC resonant parameter configuration of the U1 chip, allowing the LLC circuit to operate according to the designed working mode. N4 is the transformer auxiliary winding, used to power the chip and relay. D7, R19, CE3, R16, DZ2, Q2, and C8 form the voltage regulator circuit, stabilizing the output voltage at around 17.5V. D3, C3, C6, and CE2 form the filter circuit, filtering and stabilizing the output 17.5V to around 17V to power the U1 chip. Q1, DZ1, R10, and D2... C4 is a voltage regulator circuit that reduces 17.5V to approximately 11.5V to power the relay. When the LLC circuit malfunctions, the auxiliary winding has no output, and the relay disconnects. CY3, CY4, CY5, and CY6 are Y capacitors connected across the primary and secondary windings to meet MEC requirements. D8, D9, and CE4 are secondary output rectifiers and filters that stabilize the output voltage at 500V. C7, C9, C13, PC1, R11, R20, R21, R28, R29, R32, R33, U2, and RW1 form the output feedback circuit, providing feedback to the feedback pin of U1 to stabilize the output voltage at 500V.

[0023] In the 500V to 12V power supply circuit, U3 is a DC-DC isolation chip, which, together with C20, C21, C22, R36, R37, D10, D11, L1, and CE5, forms a buck circuit to convert 500V to 12V. L1 is an energy storage inductor, D10 is a freewheeling diode, R36 and R37 are voltage feedback sampling resistors, and CE5 is a filter electrolytic capacitor that supplies power to the downstream control circuit. In the 500V to 300-500V step-down circuit, PTC1 and PTC2 are resettable fuses, U5 is a gate driver chip used to drive the Q7 MOSFET to achieve step-down, U6 is a 12V to 12V isolated power supply used to provide drive voltage to the driver chip to drive the MOSFET, L2 is an energy storage inductor, D15 is a silicon carbide diode used for rectification, D14 is a freewheeling diode, R47, R48, R49, and C35 form the output voltage acquisition circuit used to acquire the output voltage value, LF4 is a common-mode inductor used to absorb common-mode signals, U8 is a comparator used for hardware control protection of charging current, PWM is used to control and adjust the output voltage, U9 is an operational amplifier, together with RL1 (current sampling resistor), and D16, R51, R53, R54, R56, C41, C40, C42, R58, and C43 form the output current sampling circuit, which is used by the MCU to acquire the operating current; the output voltage is adjusted by adjusting the duty cycle through the PWM output of the microcontroller. In the MCU control circuit, U4 is an LDO that converts 12V to 3.3V to power the MCU. C24, C32, C33, and C34 are filter capacitors. R43 is a series resistor between the power supply GND and the control GND, used to eliminate interference and limit fault current. TR3 is an NTC thermistor, used with R59 and C51 to measure the ambient temperature. H1 is the MCU programming port for downloading programs. JP1 is the display interface for connecting an external display to show current and voltage data. MU1 is the STM32 microcontroller. C37, C38, C39, C44, C45, LB1, RW2, RJ1, R52, R55, R57, and LED1 are the MCU's peripheral circuitry; LED1 is a working indicator light. RW2 is an adjustable resistor used to adjust the output voltage value. R38, R39, R40, and C23 form a 500V voltage acquisition circuit, which is acquired by the microcontroller. RL1 is a current sampling resistor, which supplies power to the microcontroller through the operational amplifier circuit U9 to control the charging current.

[0024] The above embodiments are merely one of the preferred embodiments of this utility model and should not be used to limit the scope of protection of this utility model. Any modifications or refinements made to the main design concept and spirit of this utility model that are not of substantial significance, but solve the same technical problem as this utility model, should be included within the scope of protection of this utility model.

Claims

1. A power supply circuit for charging an energy storage capacitor, characterized in that, It includes an input protection module, an LLC boost module, a first buck power supply module, an adjustable buck charging module, and an MCU control module; The input protection module is used to connect to AC220V mains power and realize overcurrent, overvoltage and EMC filtering protection; The LLC boost module is electrically connected to the input protection module. After rectifying and filtering the AC220V, it is converted into a stable DC500V voltage through LLC resonance and PFC power factor correction. The first step-down power supply module is electrically connected to the output terminal of the LLC boost module, which steps down the DC500V to 12V DC voltage to provide working power for the back-end control circuit. The adjustable step-down charging module is electrically connected to the output terminal of the LLC boost module, and can step down DC500V to an adjustable DC voltage of 300-500V to provide charging voltage for the energy storage capacitor; The MCU control module is electrically connected to the LLC boost module, the first buck power supply module, and the adjustable buck charging module, respectively. It is used to collect charging voltage, current and ambient temperature data, control the charging process to meet the preset charging time requirements, and shut off the charging output when the energy storage capacitor is used for circuit breaker opening and closing operations.

2. The energy storage capacitor charging power supply circuit according to claim 1, characterized in that, The input protection module includes a fuse F1, a varistor RV1, a first common-mode inductor LF1, Y capacitors CY1-CY2, and a first relay SW1. The fuse F1 provides overcurrent protection, the varistor RV1 absorbs abnormal voltage pulses, and LF1 and CY1-CY2 work together to filter common-mode interference to meet EMC requirements. The SW1 is a normally closed relay that disconnects when the downstream circuit malfunctions, cutting off the mains power input. The input protection module also includes a thermistor RT1. When the relay SW1 is open, the downstream circuit is powered through RT1. Under abnormal operating conditions, RT1 heats up and limits the current.

3. The energy storage capacitor charging power supply circuit according to claim 1, characterized in that, The LLC boost module includes a rectifier bridge DB1, a high-voltage electrolytic capacitor CE1, a combined controller U1, a resonant transformer T1, drive MOSFETs Q5-Q6, an auxiliary winding N4, and an output feedback unit. The output feedback unit consists of the seventh capacitor C7, the ninth capacitor C9, the thirteenth capacitor C13, PC1, R11, the twentieth resistor R20, the twenty-first resistor R21, the twenty-eighth resistor R28, the twenty-ninth resistor R29, the thirty-second resistor R32, the thirty-third resistor R33, U2, and RW1. It is connected to the feedback pin of the combined controller U1 to stabilize the output voltage of the LLC boost module at DC500V.

4. The energy storage capacitor charging power supply circuit according to claim 1, characterized in that, The first step-down power supply module is a BUCK step-down circuit, including a DC-DC isolation chip U3, a first energy storage inductor L1, a tenth freewheeling diode D10, a thirty-sixth voltage feedback sampling resistor R36 and a thirty-seventh voltage feedback sampling resistor R37, and a filter capacitor bank.

5. The energy storage capacitor charging power supply circuit according to claim 1, characterized in that, The adjustable buck charging module includes an overcurrent protection unit, a gate drive unit, a power conversion unit, a voltage acquisition unit, a current protection unit, and a PWM control unit.

6. The energy storage capacitor charging power supply circuit according to claim 1, characterized in that, The MCU control module includes a power conversion unit, a data acquisition unit, an interface unit, and an indicator unit; the power conversion unit includes an LDO chip U4.

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