Power distribution terminal opening and closing outlet circuit

Abstract

The utility model discloses a kind of power distribution terminal switching-in and switching-out outlet circuit, including first power switch tube, control circuit unit, switching-out relay and switching-in relay;The first end of first power switch tube is connected with the positive terminal of input power supply, the second end of first power switch tube is connected with the first end of the first normally open contact of switching-out relay and the first end of the second normally open contact of switching-in relay, the second end of first normally open contact is connected with primary switch switching-out coil, the second end of second normally open contact is connected with primary switch switching-in coil;The control end of first power switch tube is connected with the output end of control circuit unit, the input end of control circuit unit is used to input control signal, control circuit unit is used to control first power switch tube according to control signal and turn on after switching-out relay and / or switching-in relay power on, turn off before switching-out relay and / or switching-in relay power off. Lossless recovery of power distribution terminal switching-in and switching-out outlet circuit can be realized.

Description

Technical Field

[0001] This utility model relates to the field of power supply and distribution technology, and in particular to a power distribution terminal opening and closing output circuit. Background Technology

[0002] In existing distribution terminal circuits, the opening and closing output circuits directly use opening and closing relays to control the opening and closing outputs. In this case, the primary switch side opening and closing circuit has auxiliary contacts. When the opening and closing output circuit is working normally, the auxiliary contacts in the primary switch side opening and closing circuit are typically used to disconnect the operating power supply to the opening and closing coil. The distribution terminal opening and closing relay usually disconnects the output relay after the auxiliary contacts disconnect. At this time, there is no operating current in the opening and closing output circuit, and it does not affect the opening and closing contacts of the opening and closing relay. When the opening and closing relay is an onboard relay, its breaking capacity is limited. If there is an abnormality in the primary switch operating mechanism, such as the auxiliary contacts failing to separate properly or mechanical jamming, the distribution terminal opening and closing output action may be prematurely executed, i.e., the opening and closing output circuit is energized. In this case, the onboard relay contacts are very prone to damage and adhesion, leading to prolonged energization and burnout of the primary switch opening and closing coil, increasing the failure risk of the distribution terminal opening and closing output circuit. For example, existing onboard relays have a breaking capacity of 16A DC when operating on a 24V DC power supply, with some onboard relays reaching 32A DC. In practical applications, the primary switch coil is inductive, and the breaking capacity of onboard relays under inductive conditions is typically only about 50% of that under resistive loads. Furthermore, larger capacity leads to larger relay size and higher cost. Meanwhile, some existing power distribution terminals, especially substation terminals, operate on 48V DC or even higher DC voltages. From the breaking capacity parameters of existing onboard relays, it is clear that the breaking capacity of commonly used onboard relays decreases exponentially when the DC voltage exceeds 30V. Taking a 48V DC operating voltage as an example, the breaking capacity of the onboard relay under a purely resistive load is less than 30% of that under 24V DC. For inductive coils, the breaking capacity of the onboard relay contacts is even weaker. Utility Model Content

[0003] This utility model provides a switching output circuit for a power distribution terminal to improve the reliability of the switching output circuit for the power distribution terminal.

[0004] This utility model embodiment provides a power distribution terminal opening and closing output circuit, including a first power switch tube, a control circuit unit, an opening relay and a closing relay;

[0005] The first terminal of the first power switch is connected to the positive terminal of the input power supply. The second terminal of the first power switch is connected to the first terminal of the first normally open contact of the trip relay and the first terminal of the second normally open contact of the closing relay. The second terminal of the first normally open contact is connected to the trip coil of the primary switch, and the second terminal of the second normally open contact is connected to the closing coil of the primary switch. The control terminal of the first power switch is connected to the output terminal of the control circuit unit. The input terminal of the control circuit unit is used to input control signals. The control circuit unit is used to control the first power switch to conduct after the trip relay and / or the closing relay are powered on, and to turn off before the trip relay and / or the closing relay are de-energized, according to the control signals.

[0006] Optionally, the control circuit unit includes a first optocoupler, a first current-limiting resistor, and a first pull-up resistor;

[0007] The first end of the emitter of the first optocoupler is connected to the first power supply terminal through the first pull-up resistor. The second end of the emitter of the first optocoupler is used to input the control signal. The first current-limiting resistor is connected between the second end of the emitter of the first optocoupler and the first power supply terminal. The first end of the receiver of the first optocoupler is connected to the control terminal of the first power switch. The second end of the receiver of the first optocoupler is connected to the negative terminal of the input power supply.

[0008] Optionally, the control circuit unit includes an optocoupler unit and a switch control unit;

[0009] The input terminal of the optocoupler unit is used to input the control signal, and the output terminal of the optocoupler unit is connected to the control terminal of the switch control unit. The first terminal of the switch control unit is connected to the negative terminal of the input power supply, and the second terminal of the switch control unit is connected to the control terminal of the first power switch. The optocoupler unit is used to control the potential of the control terminal of the switch control unit according to the control signal, and the switch control unit is used to control the connection state between the negative terminal of the input power supply and the control terminal of the first power switch according to its control terminal potential.

[0010] Optionally, the optocoupler unit includes a second optocoupler, a second current-limiting resistor, a second pull-up resistor, and a filter capacitor;

[0011] The first end of the emitter of the second optocoupler is connected to the first power supply terminal through the second pull-up resistor. The second end of the emitter of the second optocoupler is used to input the control signal. The second current-limiting resistor is connected between the second end of the emitter of the second optocoupler and the first power supply terminal. The first end of the receiver of the second optocoupler and the first terminal of the filter capacitor are connected to the second power supply terminal. The second end of the receiver of the second optocoupler and the second terminal of the filter capacitor are connected to the control terminal of the switch control unit.

[0012] Optionally, the switch control unit includes a first voltage divider resistor, a second voltage divider resistor, and a second power switch transistor;

[0013] The first end of the first voltage divider resistor is connected to the output end of the optocoupler unit, the second end of the first voltage divider resistor and the first end of the second voltage divider resistor are connected to the control end of the second power switch, the first end of the second power switch and the second end of the second voltage divider resistor are connected to the negative end of the input power supply, and the second end of the second power switch is connected to the control end of the first power switch.

[0014] Optionally, the switching output circuit of the power distribution terminal further includes an isolation power supply; the input terminal of the isolation power supply is connected to the first power supply terminal, the output terminal of the isolation power supply is connected to the second power supply terminal, the ground terminal of the isolation power supply is connected to the negative terminal of the input power supply, and the isolation power supply is used to convert the voltage provided by the first power supply terminal into the voltage provided by the second power supply terminal.

[0015] Optionally, the switching output circuit of the power distribution terminal also includes a feedback unit;

[0016] The input terminal of the feedback unit is connected to the output terminal of the optocoupler unit or the first terminal of the photodetector of the first optocoupler. The ground terminal of the feedback unit is connected to the negative terminal of the input power supply. The output terminal of the feedback unit is used to output a feedback signal. The feedback unit is used to generate the feedback signal based on the signal output by the optocoupler unit or the first optocoupler.

[0017] Optionally, the feedback unit includes a third optocoupler, a third current-limiting resistor, a third pull-up resistor, and a fourth current-limiting resistor;

[0018] The first end of the third current-limiting resistor is connected to the output end of the optocoupler unit or the first end of the photodetector of the first optocoupler; the second end of the third current-limiting resistor is connected to the first end of the emitter of the third optocoupler; the second end of the emitter of the third optocoupler is connected to the negative end of the input power supply; the first end of the photodetector of the third optocoupler is connected to the first power supply terminal through the third pull-up resistor, and outputs the feedback signal after passing through the fourth current-limiting resistor; the second end of the photodetector of the third optocoupler is grounded.

[0019] Optionally, the feedback unit further includes a first freewheeling diode;

[0020] The anode of the first freewheeling diode is connected to the second terminal of the light emitter of the third optocoupler, and the cathode of the first freewheeling diode is connected to the negative terminal of the input power supply.

[0021] Optionally, the feedback unit further includes a second freewheeling diode;

[0022] The anode of the second freewheeling diode is connected to the second end of the light emitter of the third optocoupler, and the cathode of the second freewheeling diode is connected to the first end of the light emitter of the third optocoupler.

[0023] The technical solution of this utility model embodiment directly connects a first power switch transistor in series on the branch between the first normally open contact and the input power supply, and on the branch between the second normally open contact and the input power supply. The control unit controls the first power switch transistor to conduct after the first normally open contact or the second normally open contact closes, and to turn off before the first normally open contact or the second normally open contact opens. This ensures that no current flows when the first normally open contact or the second normally open contact operates, avoiding arcing when the first normally open contact or the second normally open contact opens, and achieving lossless recovery of the distribution terminal's opening and closing output circuit. It eliminates the contact sticking problem caused by insufficient contact breaking capacity due to a primary switch malfunction during the opening and closing process of the distribution terminal's opening and closing relays. Simultaneously, it significantly reduces the parameter performance requirements of the opening and closing relays, lowering costs in high-voltage application scenarios. Attached Figure Description

[0024] Figure 1 A schematic diagram of the opening and closing output circuit of a power distribution terminal provided for an embodiment of this utility model;

[0025] Figure 2 A schematic diagram of the opening and closing output circuit of another power distribution terminal provided in this embodiment of the present utility model;

[0026] Figure 3 A schematic diagram of the opening and closing output circuit of another power distribution terminal provided in this embodiment of the present utility model;

[0027] Figure 4 A schematic diagram of the opening and closing output circuit of another power distribution terminal provided in this embodiment of the present utility model;

[0028] Figure 5 A schematic diagram of the opening and closing output circuit of another power distribution terminal provided in this embodiment of the present utility model. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0030] Figure 1 This is a schematic diagram of the opening and closing output circuit of a power distribution terminal provided for an embodiment of this utility model. (See diagram below.) Figure 1 As shown, the switching output circuit of the power distribution terminal includes a first power switch Q1, a control circuit unit 110, a switching relay, and a closing relay. The first terminal of the first power switch Q1 is connected to the positive terminal KM+ of the input power supply, and the second terminal of the first power switch Q1 is connected to the first terminal of the first normally open contact RFZ of the switching relay and the first terminal of the second normally open contact RHZ of the closing relay. The second terminal of the first normally open contact RFZ is connected to the switching coil of the primary switch, and the second terminal of the second normally open contact RHZ is connected to the closing coil of the primary switch. The control terminal of the first power switch Q1 is connected to the output terminal of the control circuit unit 110. The input terminal of the control circuit unit 110 is used to input the control signal DO-YZ. The control circuit unit 110 is used to control the first power switch Q1 to conduct after the switching relay and / or the closing relay are powered on, and to turn off before the switching relay and / or the closing relay are de-energized, according to the control signal DO-YZ.

[0031] Specifically, the distribution terminal can be a feeder terminal unit (FTU), a substation terminal unit (DTU), or a transformer terminal unit (TTU). The first power switch Q1 can be a P-type MOSFET or a P-type IGBT. The first power switch Q1 and the first normally open contact RFZ are connected in series between the input power supply and the primary switch opening coil, and the first power switch Q1 and the second normally open contact RHZ are connected in series between the input power supply and the primary switch closing coil. The control circuit unit 110 is used to control the first power switch Q1 to turn on or off according to the control signal DO-YZ. During the remote control or protection control process of the distribution terminal opening and closing output circuit, the opening relay and closing relay can be energized first, that is, the first normally open contact RFZ or the second normally open contact RHZ is closed. At this time, the first power switch Q1 is in the off state, and the current provided by the positive terminal KM+ of the input power supply cannot be transmitted to the first normally open contact RFZ and the second normally open contact RHZ, so that the first normally open contact RFZ or the second normally open contact RHZ has no overcurrent risk. Then, the control circuit unit 110 controls the first power switch Q1 to conduct according to the control signal DO-YZ, so that the current provided by the positive terminal KM+ of the input power supply is transmitted to the primary switch tripping coil, controlling the primary switch tripping coil to be energized, realizing the safe operation of the primary switch. After the power distribution terminal completes the tripping and closing operation output, the control circuit unit 110 controls the first power switch Q1 to turn off according to the control signal DO-YZ. Since the first power switch Q1 is turned off by its own PN junction undervoltage, there is no risk of arcing of the relay physical contacts. At this time, the current provided by the positive terminal KM+ of the input power supply cannot be transmitted to the first normally open contact RFZ and the second normally open contact RHZ, and then the tripping relay and the closing relay are de-energized, so that no current flows when the first normally open contact RFZ and the second normally open contact RHZ are disconnected, avoiding the arcing of the first normally open contact RFZ and the second normally open contact RHZ when disconnected, realizing the lossless recovery of the power distribution terminal tripping and closing output circuit. It eliminates the contact sticking problem caused by insufficient contact breaking capacity of the opening and closing relays in the power distribution terminal during the opening and closing process due to a primary switch malfunction. At the same time, it can significantly reduce the parameter performance requirements of the opening and closing relays, and even use signal relays with corresponding current carrying capacity to achieve high voltage DC output control. It is especially valuable in DC 48V and above application scenarios.

[0032] The technical solution of this embodiment connects a first power switch directly in series with the first normally open contact and the input power supply branch, and with the second normally open contact and the input power supply branch. The control unit controls the first power switch to conduct after the first or second normally open contact closes and to turn off before the first or second normally open contact opens. This ensures that no current flows when the first or second normally open contact operates, avoiding arcing when the first or second normally open contact breaks, and achieving lossless recovery of the distribution terminal's opening and closing output circuit. It eliminates the contact sticking problem caused by insufficient contact breaking capacity due to a primary switch malfunction during the opening and closing process of the distribution terminal's opening and closing relays. Simultaneously, it significantly reduces the parameter performance requirements of the opening and closing relays, lowering costs in high-voltage applications.

[0033] Figure 2 This is a schematic diagram of another power distribution terminal's opening and closing output circuit provided as an embodiment of the present utility model. (See diagram below.) Figure 2 As shown, the control circuit unit 110 includes a first optocoupler U1, a first current-limiting resistor Rs1, and a first pull-up resistor Rt1. The first end of the emitter of the first optocoupler U1 is connected to the first power supply terminal V1 through the first pull-up resistor Rt1. The second end of the emitter of the first optocoupler U1 is used to input the control signal DO-YZ. The first current-limiting resistor Rs1 is connected between the second end of the emitter of the first optocoupler U1 and the first power supply terminal V1. The first end of the receiver of the first optocoupler U1 is connected to the control terminal of the first power switch Q1. The second end of the receiver of the first optocoupler U1 is connected to the negative terminal KM- of the input power supply.

[0034] Specifically, the first optocoupler U1 can be a Darlington-type isolated optocoupler. In this case, the secondary side of the first optocoupler U1 has a high current-carrying capacity, allowing the control signal DO-YZ to directly control the conduction or cutoff of the first power switch Q1 through the first optocoupler U1, achieving no-current operation of the first normally open contact RFZ and the second normally open contact RHZ. For example, the first power switch Q1 is a P-type transistor, and the power supplied by the first power supply terminal V1 can be the power supply of the distribution terminal's low-voltage system. When controlling the closing of the distribution terminal's circuit breaker outlet, the control signal DO-YZ is first kept at a high level. The voltage difference across the emitter (primary side) of the first optocoupler U1 prevents it from emitting light, meaning the first optocoupler U1 cannot control the first power switch Q1 to conduct. Then, the closing relay is activated, causing the second normally open contact RHZ to close, preventing the second normally open contact RHZ from being energized. After the second normally open contact RHZ completes its operation, the control signal DO-YZ goes low. The voltage difference across the emitter of the first optocoupler U1 causes it to emit light, thus conducting across the receiver of the first optocoupler U1. At this time, the control terminal potential of the first power switch Q1 is pulled down to the negative terminal KM- of the input power supply, ensuring that the difference between the potential at the first terminal of the first power switch Q1 and the potential at the control terminal satisfies the conduction condition of the first power switch Q1, allowing it to conduct. The voltage provided by the positive terminal KM+ of the input power supply can then be transmitted to the primary switch closing coil through the first power switch Q1 and the second normally open contact RHZ, controlling the closing of the distribution terminal's opening and closing output. After the distribution terminal's opening and closing output completes the closing action, the control signal DO-YZ can be made high, controlling the first power switch Q1 to turn off through the first optocoupler U1, preventing the current at the positive terminal KM+ of the input power supply from being transmitted to the second normally open contact RHZ. Then, the closing relay is de-energized, causing the second normally open contact RHZ to open, thereby avoiding the arcing situation when the second normally open contact RHZ is disconnected, and realizing the lossless recovery of the opening and closing output circuit of the power distribution terminal.

[0035] Similarly, when controlling the opening and closing of the distribution terminal's circuit breaker, the control signal DO-YZ can be kept high to turn off the first power switch Q1. Then, the opening relay is activated, closing the first normally open contact RFZ. After the first normally open contact RFZ has closed, the control signal DO-YZ is set low to turn on the first power switch Q1. At this time, the voltage provided by the positive terminal KM+ of the input power supply can be transmitted to the primary switch's opening coil through the first power switch Q1 and the first normally open contact RFZ, controlling the opening of the distribution terminal's circuit breaker. After the distribution terminal's circuit breaker completes the opening action, the control signal DO-YZ can be set high to turn off the first power switch Q1. Then, the opening relay is de-energized, causing the first normally open contact RFZ to open. This avoids arcing when the first normally open contact RFZ opens, achieving lossless recovery of the distribution terminal's circuit breaker's output circuit.

[0036] Continue to refer to Figure 2 A first resistor R1 is connected between the control terminal and the first terminal of the first power switch Q1, so that when the two ends of the photodetector (secondary side) of the first optocoupler U1 are turned on, there is a voltage difference between the control terminal and the first terminal of the first power switch Q1. At this time, the conduction condition of the first power switch Q1 is: (v1 / rt1)×β1>km / r1, and km-vu2>vDGq1; where v1 is the voltage provided by the first power supply terminal V1, rt1 is the resistance value of the first pull-up resistor Rt1; β1 is the current transfer ratio (CTR) of the first optocoupler U1, km is the voltage provided by the input power supply, r1 is the resistance value of the first resistor R1, vu2 is the voltage across the photodetector of the first optocoupler U1, and vDGq1 is the threshold voltage of the first power switch Q1.

[0037] Figure 3 This is a schematic diagram of another power distribution terminal's opening and closing output circuit provided as an embodiment of the present utility model. (See diagram below.) Figure 3 As shown, the control circuit unit 110 includes an optocoupler unit 111 and a switch control unit 112. The input terminal of the optocoupler unit 111 is used to input the control signal DO-YZ, and the output terminal of the optocoupler unit 111 is connected to the control terminal of the switch control unit 112. The first terminal of the switch control unit 112 is connected to the negative terminal KM- of the input power supply, and the second terminal of the switch control unit 112 is connected to the control terminal of the first power switch Q1. The optocoupler unit 111 is used to control the potential of the control terminal of the switch control unit 112 according to the control signal DO-YZ. The switch control unit 112 is used to control the connection state between the negative terminal KM- of the input power supply and the control terminal of the first power switch Q1 according to its control terminal potential.

[0038] Specifically, when the control terminal potential of the switch control unit 112 is at an effective level, the first and second terminals of the switch control unit 112 are connected, making the negative terminal KM- of the input power supply and the control terminal of the first power switch Q1 connected. This ensures that the voltage difference between the control terminal potential and the first terminal potential of the first power switch Q1 satisfies the conduction condition of the first power switch Q1, and the first power switch Q1 conducts. When the control terminal potential of the switch control unit 112 is at an ineffective level, the first and second terminals of the switch control unit 112 are turned off, and the negative terminal KM- of the input power supply and the control terminal of the first power switch Q1 are disconnected. The voltage difference between the control terminal potential and the first terminal potential of the first power switch Q1 cannot satisfy the conduction condition of the first power switch Q1, and the first power switch Q1 is turned off. For example, the effective level of the control terminal potential of the switch control unit 112 can be a high level. When the control signal DO-YZ is high, the optocoupler unit 111 controls the control terminal of the switch control unit 112 to be low according to the control signal DO-YZ. The switch control unit 112, due to the low level of the control terminal, cannot connect the negative terminal KM- of the input power supply to the control terminal of the power switch Q1, thus turning the first power switch Q1 off. When the control signal DO-YZ is low, the optocoupler unit 111 controls the control terminal of the switch control unit 112 to be high according to the control signal DO-YZ. The switch control unit 112, due to the high level of the control terminal, connects the negative terminal KM- of the input power supply to the control terminal of the power switch Q1, thus turning the first power switch Q1 on.

[0039] Continue to refer to Figure 3 The optocoupler unit 111 includes a second optocoupler U2, a second current-limiting resistor Rs2, a second pull-up resistor Rt2, and a filter capacitor C1. The first end of the emitter of the second optocoupler U2 is connected to the first power supply terminal V1 through the second pull-up resistor Rt2. The second end of the emitter of the second optocoupler U2 is used to input control signals DO-YZ. The second current-limiting resistor Rs2 is connected between the second end of the emitter of the second optocoupler U2 and the first power supply terminal V1. The first end of the receiver of the second optocoupler U2 and the first terminal of the filter capacitor C1 are connected to the second power supply terminal V2. The second end of the receiver of the second optocoupler U2 and the second terminal of the filter capacitor C1 are connected to the control terminal of the switch control unit 112.

[0040] Specifically, when the control signal DO-YZ is high, the voltage difference across the emitter (primary side) of the second optocoupler U2 prevents it from emitting light, thus disconnecting the receiver (secondary side) of the second optocoupler U2. The high-level signal provided by the second power supply V2 cannot be transmitted to the control terminal of the switch control unit 112, causing the first and second terminals of the switch control unit 112 to be disconnected. Consequently, the negative terminal KM- of the input power supply and the control terminal of the first power switch Q1 are disconnected, and the first power switch Q1 is off. When the control signal DO-YZ is low, the voltage difference across the emitter of the second optocoupler U2 causes it to emit light, thus conducting the receiver of the second optocoupler U2. The high-level signal provided by the second power supply terminal V2 is transmitted to the control terminal of the switch control unit 112, enhancing the driving capability of the control signals DO-YZ. This connects the first and second terminals of the switch control unit 112, connecting the negative terminal KM- of the input power supply to the control terminal of the first power switch Q1. This ensures that the voltage difference between the control terminal potential and the first terminal potential of the first power switch Q1 satisfies the conduction condition of Q1, thus turning on Q1. The filter capacitor C1 filters the high-level signal provided by the second power supply terminal V2, ensuring its voltage stability and consequently guaranteeing the connectivity stability of the switch control unit 112.

[0041] Continue to refer to Figure 3 The switch control unit 112 includes a first voltage divider resistor R11, a second voltage divider resistor R12, and a second power switch Q2. The first end of the first voltage divider resistor R11 is connected to the output end of the optocoupler unit 111, the second end of the first voltage divider resistor R11 and the first end of the second voltage divider resistor R12 are connected to the control end of the second power switch Q2, the first end of the second power switch Q2 and the second end of the second voltage divider resistor R12 are connected to the negative terminal KM- of the input power supply, and the second end of the second power switch Q2 is connected to the control end of the first power switch Q1.

[0042] Specifically, when the control signal DO-YZ is low, the current on the emitter of the second optocoupler U2 is v1 / rt2, causing the emitter of the second optocoupler U2 to emit light, and the two ends of the receiver of the second optocoupler U2 to conduct; where v1 is the voltage provided by the first power supply terminal V1, and rt2 is the resistance value of the second pull-up resistor Rt2. At this time, the voltage provided by the second power supply terminal V2 is transmitted to the first end of the first voltage divider resistor R11. The first voltage divider resistor R11 and the second voltage divider resistor R12 divide the voltage, controlling the second power switch Q2 to conduct. The potential of the control terminal of the first power switch Q1 is pulled down to the potential provided by the negative terminal KM- of the input power supply. The positive terminal KM+ of the input power supply forms an electrical circuit through the first resistor R1 and the negative terminal KM- of the input power supply. A voltage drop is formed between the first terminal and the control terminal of the first power switch Q1. When the voltage difference between the first terminal and the control terminal of the first power switch Q1 meets the conduction condition of the first power switch Q1, the first power switch Q1 conducts. For example, the conduction condition of the first power switch Q1 is: (v1 / rt2)×β2>v2 / (r11+r12), and v2×r12 / (r11+r12)>vDGq2; at the same time, the current Icq2 at the second terminal of the second power switch Q2>km / r1, and km-vDGq1>vDGq2. Wherein, v1 is the voltage provided by the first power supply terminal V1, rt2 is the resistance value of the second pull-up resistor Rt2, r11 is the resistance value of the first voltage divider resistor R11, r12 is the resistance value of the second voltage divider resistor R12, β2 is the current transfer ratio (CTR) of the second optocoupler U2, v2 is the voltage provided by the second power supply terminal V2, vDGq2 is the threshold voltage of the second power switch Q2, Icq2 is the current at the second terminal of the second power switch Q2, km is the voltage provided by the input power supply, r1 is the resistance value of the first resistor R1, and vDGq1 is the threshold voltage of the first power switch Q1.

[0043] When the control signal DO-YZ is high, the current in the emitter of the second optocoupler U2 disappears, and the two ends of the receiver of the second optocoupler U2 are disconnected. At this time, the voltage at the control terminal of the second power switch Q2 disappears, making the first and second terminals of the second power switch Q2 disconnected. Therefore, the voltage at the first terminal and the control terminal of the first power switch Q1 are equal, and the first power switch Q1 is turned off.

[0044] Continue to refer to Figure 3The power distribution terminal circuit also includes an isolation power supply 120; the input terminal of the isolation power supply 120 is connected to the first power supply terminal V1, the output terminal of the isolation power supply 120 is connected to the second power supply terminal V2, and the ground terminal of the isolation power supply 120 is connected to the negative terminal KM- of the input power supply. The isolation power supply 120 is used to convert the voltage provided by the first power supply terminal V1 into the voltage provided by the second power supply terminal V2.

[0045] Specifically, the ground terminal of the isolation power supply 120 is connected to the negative terminal KM- of the input power supply, which enables the isolation power supply 120 and the input power supply to share a common ground. This allows the voltage provided by the second power supply terminal V2 to be relative to the voltage of the first terminal of the second power switch Q2. The voltage provided by the second power supply terminal V2 is divided by the first voltage divider resistor R11 and the second voltage divider resistor R12, which satisfies the conduction condition of the second power switch Q2.

[0046] Figure 4 This is a schematic diagram of another power distribution terminal's opening and closing output circuit provided as an embodiment of the present utility model. (See diagram below.) Figure 4 As shown, the power distribution terminal's opening and closing output circuit also includes a feedback unit 130; the input terminal of the feedback unit 130 is connected to the output terminal of the optocoupler unit 111 or the first end of the photodetector of the first optocoupler U1, the ground terminal of the feedback unit 130 is connected to the negative terminal KM- of the input power supply, and the output terminal of the feedback unit 130 is used to output a feedback signal YZFJ; the feedback unit 130 is used to form a feedback signal YZFJ based on the signal output by the optocoupler unit 111 or the first optocoupler U1.

[0047] Specifically, Figure 4 The example shows that the first input terminal of the feedback unit 130 is connected to the output terminal of the optocoupler unit 111, allowing it to receive the voltage value output by the optocoupler unit 111. The ground terminal of the feedback unit 130 is connected to the negative terminal KM- of the input power supply, ensuring that the voltage received by the feedback unit 130 is relative to the voltage at the first terminal of the switch control unit 112, thus guaranteeing the accuracy of the voltage received by the feedback unit 130. When the control signal DO-YZ is high, the voltage value output by the optocoupler unit 111 is an invalid level (e.g., ...). Figure 3 When the control signal DO-YZ is at a low level, the feedback unit 130 outputs a first-level feedback signal YZFJ based on the optocoupler unit 111, which is used to characterize that the control signal DO-YZ is at a high level. When the control signal DO-YZ is at a low level, the voltage value output by the optocoupler unit 111 is at an effective level (e.g., low level). Figure 3When the signal is at a high level (as indicated by the high level in the image), the feedback unit 130 outputs a second-level feedback signal YZFJ based on the optocoupler unit 111, which is used to characterize the control signal DO-YZ as low. The feedback signal YZFJ can be output to the control unit of the power distribution terminal, so that the control unit can determine the state of the control signal DO-YZ based on the level of the feedback signal YZFJ.

[0048] For example, the feedback unit 130 includes a third optocoupler U3, a third current-limiting resistor Rs3, a third pull-up resistor Rt3, and a fourth current-limiting resistor Rs4; the first end of the third current-limiting resistor Rs3 is connected to the output terminal of the optocoupler unit 111 or the first end of the photodetector of the first optocoupler U1, the second end of the third current-limiting resistor Rs3 is connected to the first end of the emitter of the third optocoupler U3, and the second end of the emitter of the third optocoupler U3 is connected to the negative terminal KM- of the input power supply; the first end of the photodetector of the third optocoupler U3 is connected to the first power supply terminal V1 through the third pull-up resistor Rt3, and outputs the feedback signal YZFJ after passing through the fourth current-limiting resistor Rs4; the second end of the photodetector of the third optocoupler U3 is grounded to GND.

[0049] Specifically, when the control signal DO-YZ is high, the voltage output of optocoupler unit 111 can be low. The current in the emitter of the third optocoupler U3 is insufficient to make it emit light, and the two ends of the receiver of the third optocoupler U3 are disconnected. Therefore, the potential of the first end of the receiver of the third optocoupler U3 is pulled up to a high level through the third pull-up resistor Rt3, i.e., the feedback signal YZFJ is high. When the control signal DO-YZ is low, the voltage output of optocoupler unit 111 can be high. The current in the emitter of the third optocoupler U3 makes it emit light, and the two ends of the receiver of the third optocoupler U3 are connected. Therefore, the potential of the first end of the receiver of the third optocoupler U3 drops to the potential of ground GND, i.e., the feedback signal YZFJ is low. Thus, the feedback collection of the control signal DO-YZ can be achieved through the feedback signal YZFJ, facilitating the logic control of the power distribution terminal.

[0050] Continue to refer to Figure 4 The feedback unit 130 also includes a first freewheeling diode D1; the anode of the first freewheeling diode D1 is connected to the second terminal of the light emitter of the third optocoupler U3, and the cathode of the first freewheeling diode D1 is connected to the negative terminal KM- of the input power supply.

[0051] Specifically, the negative terminal KM- of the input power supply is the external voltage. When the external voltage is unstable (including electrostatic discharge in the external environment and voltage surges), the external voltage should be prevented from affecting the voltage of the second power supply terminal V2.

[0052] Continue to refer to Figure 4The feedback unit 130 also includes a second freewheeling diode D2; the anode of the second freewheeling diode D2 is connected to the second end of the light emitter of the third optocoupler U3, and the cathode of the second freewheeling diode D2 is connected to the first end of the light emitter of the third optocoupler U3.

[0053] Specifically, the second freewheeling diode D2 is connected to both ends of the emitter of the third optocoupler U3. When there is a reverse voltage across the emitter of the third optocoupler U3, this reverse voltage can be discharged through the second freewheeling diode D2, thereby preventing damage to the third optocoupler U3 and improving its reliability.

[0054] It should be noted that, Figure 4 This is merely an example illustration showing the input of feedback unit 130 connected to the output of optocoupler unit 111. Figure 5 This is a schematic diagram of another power distribution terminal's opening and closing output circuit provided as an embodiment of the present utility model. (See diagram below.) Figure 5 As shown, the input terminal of the feedback unit 130 can also be connected to the output terminal of the first optocoupler U1. In this case, a feedback signal YZFJ can be formed based on the voltage output by the first optocoupler U1. When the control signal DO-YZ is high, the voltage output by the first optocoupler U1 can be high, and the current in the emitter of the third optocoupler U3 causes it to emit light. The two ends of the receiver of the third optocoupler U3 are connected, so the potential of the first end of the receiver of the third optocoupler U3 drops to ground (GND), meaning the feedback signal YZFJ is low. When the control signal DO-YZ is low, the voltage output by the first optocoupler U1 can be low, and the current in the emitter of the third optocoupler U3 is insufficient to cause it to emit light. The two ends of the receiver of the third optocoupler U3 are disconnected, so the potential of the first end of the receiver of the third optocoupler U3 is pulled up to a high level through the third pull-up resistor Rt3, meaning the feedback signal YZFJ is high. Thus, the feedback collection of the control signal DO-YZ can be achieved through the feedback signal YZFJ, facilitating the logic control of the power distribution terminal. At this time, the state of the control signal DO-YZ fed back by the feedback signal YZFJ is... Figure 4 The feedback control signals DO-YZ have opposite states, but the principle is similar.

[0055] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A power distribution terminal opening and closing outlet circuit, characterized by, It includes a first power switch, a control circuit unit, a tripping relay, and a closing relay; The first terminal of the first power switch is connected to the positive terminal of the input power supply. The second terminal of the first power switch is connected to the first terminal of the first normally open contact of the trip relay and the first terminal of the second normally open contact of the closing relay. The second terminal of the first normally open contact is connected to the trip coil of the primary switch, and the second terminal of the second normally open contact is connected to the closing coil of the primary switch. The control terminal of the first power switch is connected to the output terminal of the control circuit unit. The input terminal of the control circuit unit is used to input control signals. The control circuit unit is used to control the first power switch to conduct after the trip relay and / or the closing relay are powered on, and to turn off before the trip relay and / or the closing relay are de-energized, according to the control signals.

2. The distribution terminal switching output circuit according to claim 1, characterized in that, The control circuit unit includes a first optocoupler, a first current-limiting resistor, and a first pull-up resistor; The first end of the emitter of the first optocoupler is connected to the first power supply terminal through the first pull-up resistor. The second end of the emitter of the first optocoupler is used to input the control signal. The first current-limiting resistor is connected between the second end of the emitter of the first optocoupler and the first power supply terminal. The first end of the receiver of the first optocoupler is connected to the control terminal of the first power switch. The second end of the receiver of the first optocoupler is connected to the negative terminal of the input power supply.

3. The power distribution terminal opening and closing outlet circuit according to claim 1, characterized in that, The control circuit unit includes an optocoupler unit and a switch control unit; The input terminal of the optocoupler unit is used to input the control signal, and the output terminal of the optocoupler unit is connected to the control terminal of the switch control unit. The first terminal of the switch control unit is connected to the negative terminal of the input power supply, and the second terminal of the switch control unit is connected to the control terminal of the first power switch. The optocoupler unit is used to control the potential of the control terminal of the switch control unit according to the control signal, and the switch control unit is used to control the connection state between the negative terminal of the input power supply and the control terminal of the first power switch according to its control terminal potential.

4. A power distribution terminal opening and closing outlet circuit according to claim 3, characterized in that, The optocoupler unit includes a second optocoupler, a second current-limiting resistor, a second pull-up resistor, and a filter capacitor; The first end of the emitter of the second optocoupler is connected to the first power supply terminal through the second pull-up resistor. The second end of the emitter of the second optocoupler is used to input the control signal. The second current-limiting resistor is connected between the second end of the emitter of the second optocoupler and the first power supply terminal. The first end of the receiver of the second optocoupler and the first terminal of the filter capacitor are connected to the second power supply terminal. The second end of the receiver of the second optocoupler and the second terminal of the filter capacitor are connected to the control terminal of the switch control unit.

5. A power distribution terminal opening and closing outlet circuit according to claim 4, characterized in that, The switch control unit includes a first voltage divider resistor, a second voltage divider resistor, and a second power switch transistor; The first end of the first voltage divider resistor is connected to the output end of the optocoupler unit, the second end of the first voltage divider resistor and the first end of the second voltage divider resistor are connected to the control end of the second power switch, the first end of the second power switch and the second end of the second voltage divider resistor are connected to the negative end of the input power supply, and the second end of the second power switch is connected to the control end of the first power switch.

6. A power distribution terminal opening and closing outlet circuit according to claim 5, characterized in that, It also includes an isolated power supply; the input terminal of the isolated power supply is connected to the first power supply terminal, the output terminal of the isolated power supply is connected to the second power supply terminal, and the ground terminal of the isolated power supply is connected to the negative terminal of the input power supply. The isolated power supply is used to convert the voltage provided by the first power supply terminal into the voltage provided by the second power supply terminal.

7. Power distribution terminal opening and closing outlet circuit according to any of claims 2-6, characterized in that, It also includes a feedback unit; The input terminal of the feedback unit is connected to the output terminal of the optocoupler unit or the first terminal of the photodetector of the first optocoupler; the ground terminal of the feedback unit is connected to the negative terminal of the input power supply; and the output terminal of the feedback unit is used to output a feedback signal. The feedback unit is used to generate the feedback signal based on the signal output by the optocoupler unit or the first optocoupler.

8. A power distribution terminal opening and closing outlet circuit according to claim 7, characterized in that, The feedback unit includes a third optocoupler, a third current-limiting resistor, a third pull-up resistor, and a fourth current-limiting resistor; The first end of the third current-limiting resistor is connected to the output end of the optocoupler unit or the first end of the photodetector of the first optocoupler; the second end of the third current-limiting resistor is connected to the first end of the emitter of the third optocoupler; the second end of the emitter of the third optocoupler is connected to the negative end of the input power supply; the first end of the photodetector of the third optocoupler is connected to the first power supply terminal through the third pull-up resistor, and outputs the feedback signal after passing through the fourth current-limiting resistor; the second end of the photodetector of the third optocoupler is grounded.

9. A power distribution terminal opening and closing outlet circuit according to claim 8, characterized in that, The feedback unit further includes a first freewheeling diode; The anode of the first freewheeling diode is connected to the second terminal of the light emitter of the third optocoupler, and the cathode of the first freewheeling diode is connected to the negative terminal of the input power supply.

10. The power distribution terminal opening and closing outlet circuit according to claim 8, characterized in that, The feedback unit also includes a second freewheeling diode; The anode of the second freewheeling diode is connected to the second end of the light emitter of the third optocoupler, and the cathode of the second freewheeling diode is connected to the first end of the light emitter of the third optocoupler.

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