A solid-state circuit breaker and a power-off processing method thereof

Abstract

A solid-state circuit breaker and a power-off processing method thereof, comprising a mechanical switch, a control circuit, a power electronic device and a power supply unit, wherein the mechanical switch comprises a contact mechanism and a control coil for driving the contact mechanism, the contact mechanism comprises a main contact and an auxiliary contact, the main contact and the power supply unit are connected to the input end of the circuit breaker, the power electronic device is connected in series between the main contact and the output end of the circuit breaker, the power supply unit is connected to the control circuit for supplying power to the control circuit, the auxiliary contact and the control coil are respectively connected to the control circuit, the power electronic device is connected to the control circuit, the control circuit drives the mechanical switch and the power electronic device to operate after receiving a control signal, the control circuit has a memory unit, after the power supply of the control circuit is interrupted and restored, the control circuit drives the mechanical switch and the power electronic device by reading the control signal in the memory unit. The present application overcomes the defect that the solid-state circuit breaker needs to be reclosed from the outside after power failure, and the operation is convenient.

Description

Technical Field

[0001] The present invention relates to the field of circuit breakers, and in particular to a solid-state circuit breaker and a power-off processing method thereof. Background Art

[0002] Solid-state circuit breakers are increasingly used in flexible AC transmission systems due to their fast switching, reliability, and repeatability. They are also used in conjunction with other devices to greatly improve the stability and reliability of power systems. Existing solid-state circuit breakers cannot be completely separated from mechanical switches. Usually, solid-state circuit breakers need to be equipped with mechanical switches as electrical isolation. By disconnecting the mechanical switch, leakage current can be avoided in power electronic devices. However, solid-state circuit breakers usually draw power from the main circuit. When the main circuit loses power, the electromagnetic mechanical switch in the solid-state circuit breaker will also be disconnected. At this time, if power needs to be turned on again, the outside world needs to re-close the switch, which is extremely inconvenient. Summary of the invention

[0003] The object of the present invention is to overcome the defects of the prior art and provide a solid-state circuit breaker which does not need to be reclosed after power failure and a power failure processing method thereof.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A solid-state circuit breaker comprises a mechanical switch, a control circuit, a power electronic device and a power supply unit, wherein the mechanical switch comprises a contact mechanism and a control coil for driving the contact mechanism to move, the contact mechanism comprises a main contact and at least one auxiliary contact that moves synchronously with the main contact, one end of the main contact and one end of the power supply unit are connected to an input end of the circuit breaker, the power electronic device is connected in series to a main line between the other end of the main contact and an output end of the circuit breaker, the other end of the power supply unit is connected to the control circuit for supplying power to the control circuit, the auxiliary contact is connected to the control circuit for feeding back the action state of the contact mechanism, the control coil is connected to the control circuit and moves the contact mechanism under the drive of the control circuit, the power electronic device is connected to the control circuit, and drives the mechanical switch and the power electronic device to move after the control circuit receives a control signal;

[0006] The control circuit has a memory unit. After the power supply of the control circuit is interrupted and restored, the control circuit drives the mechanical switch and the power electronic device by reading the control signal before the power supply is interrupted in the memory unit.

[0007] Preferably, it further comprises a current detection unit, wherein the current detection unit is connected between the mechanical switch and the power electronic device, and the current detection unit is connected to the control circuit for transmitting the current signal to the control circuit.

[0008] Preferably, the control circuit is also connected to a human-machine interface, and the human-machine interface is used to send a control signal for controlling the opening and closing of the circuit breaker to the control circuit.

[0009] Preferably, the control circuit is further connected to a communication unit, which is connected to an external host computer, and is used to transmit a control signal generated by the host computer for controlling the opening and closing of the circuit breaker to the control circuit.

[0010] Preferably, the control circuit is further connected to a DIP switch, and the DIP switch transmits a control signal for controlling the opening and closing of the circuit breaker to the control circuit.

[0011] A method for processing power failure of a solid-state circuit breaker, comprising the solid-state circuit breaker as described above, wherein when the control circuit is powered normally, the control circuit receives a control signal for controlling the opening and closing of the circuit breaker, and stores the control signal in a memory unit of the control circuit, and the control circuit drives a mechanical switch and a power electronic device to operate according to the control signal;

[0012] After the power supply to the control circuit is interrupted and then restored to normal, the control circuit reads the control signal stored in the memory unit for the last time before the power failure. When the control signal read by the control circuit is a closing command, the control circuit drives the mechanical switch and the power electronic device to operate respectively; when the control signal read by the control circuit is an opening command, the control circuit does not drive the mechanical switch and the power electronic device to operate.

[0013] Furthermore, when the control circuit is normally powered and the solid-state circuit breaker is in an open state, after the control circuit obtains a closing command by receiving or reading a memory unit, the control circuit first drives the contact mechanism of the mechanical switch to close, and then drives the power electronic device to close;

[0014] When the control circuit is powered normally and the solid-state circuit breaker is in the open state, after the control circuit obtains the opening command by reading the memory unit, the control circuit does not drive the power electronic device or the mechanical switch to operate;

[0015] When the control circuit is powered normally and the solid-state circuit breaker is in the closed state, after the control circuit receives the opening command, the control circuit first drives the power electronic device to close and then drives the contact mechanism of the mechanical switch to open, and the auxiliary contact opens earlier than the main contact.

[0016] Furthermore, when the control circuit drives the contact mechanism to close, the main contact of the contact mechanism closes before the auxiliary contact, and after the auxiliary contact closes, it feeds back to the control circuit that the contact mechanism is in a closed state; when the control circuit drives the contact mechanism to open, the auxiliary contact of the contact mechanism opens before the main contact.

[0017] Furthermore, the control signal received and stored by the control circuit includes a closing command, which may come from a human-machine interface connected to the control circuit, or the closing command may be transmitted by a communication unit connected to the control circuit, or the closing command may come from a dip switch connected to the control circuit.

[0018] Furthermore, the control signal received and stored by the control circuit includes a trip command, which may come from a human-machine interface connected to the control circuit, or the trip command may be transmitted by a communication unit connected to the control circuit, or the trip command may come from a dip switch connected to the control circuit, or the trip command may come from a short-circuit protection mechanism or an overload protection mechanism of a solid-state circuit breaker.

[0019] A solid-state circuit breaker and a power-off processing method thereof of the present invention are provided with a memory unit for recording the opening and closing control signal of the circuit breaker in the control circuit. After the power supply of the control circuit is interrupted and then restored, the control circuit obtains the control signal of the circuit breaker before the power failure in the memory unit, and drives the mechanical switch and the power electronic device to operate respectively according to the control signal, thereby overcoming the defect of needing to reclose the circuit breaker from an external operation after power failure, and the operation is convenient.

[0020] In addition, the power supply unit and the mechanical switch are both connected to the input end of the circuit breaker, and the power supply unit supplies power to the control circuit without being controlled by the mechanical switch or the power electronic appliance.

[0021] In addition, the control circuit can be controlled through a human-machine interface, or controlled by an external host computer through a communication unit, or controlled by a dip switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of a solid-state circuit breaker of the present invention;

[0023] Figure 2 It is a schematic diagram of a first embodiment of a solid-state circuit breaker of the present invention. DETAILED DESCRIPTION

[0024] The following is combined with Figure 1-2 The given embodiments further illustrate the specific implementation of a solid-state circuit breaker and a power-off processing method thereof of the present invention. A solid-state circuit breaker and a power-off processing method thereof of the present invention are not limited to the description of the following embodiments.

[0025] A solid-state circuit breaker comprises a mechanical switch, a control circuit, a power electronic device and a power supply unit, wherein the mechanical switch comprises a contact mechanism and a control coil for driving the contact mechanism to move, the contact mechanism comprises a main contact and at least one auxiliary contact that moves synchronously with the main contact, one end of the main contact and one end of the power supply unit are connected to the input end of the circuit breaker, the power electronic device is connected in series to a main line between the other end of the main contact and the output end of the circuit breaker, the other end of the power supply unit is connected to the control circuit for supplying power to the control circuit, the auxiliary contact is connected to the control circuit for feeding back the action state of the contact mechanism, the control coil is connected to the control circuit and drives the contact mechanism to move when driven by the control circuit, the power electronic device is connected to the control circuit, and drives the mechanical switch and the power electronic device to move after the control circuit receives a control signal;

[0026] The control circuit has a memory unit. After the power supply of the control circuit is interrupted and restored, the control circuit drives the mechanical switch and the power electronic device by reading the control signal before the power supply is interrupted in the memory unit.

[0027] When the control circuit is powered normally, the control circuit receives a control signal for controlling the opening and closing of the circuit breaker, and stores the control signal in a memory unit of the control circuit. The control circuit drives the mechanical switch and the power electronic device to operate according to the control signal.

[0028] After the power supply to the control circuit is interrupted and then restored to normal, the control circuit reads the control signal stored in the memory unit for the last time before the power failure. When the control signal read by the control circuit is a closing command, the control circuit drives the mechanical switch and the power electronic device to operate respectively; when the control signal read by the control circuit is an opening command, the control circuit does not drive the mechanical switch and the power electronic device to operate.

[0029] A solid-state circuit breaker and a power-off processing method thereof of the present invention are provided with a memory unit for recording the opening and closing control signal of the circuit breaker in the control circuit. After the power supply of the control circuit is interrupted and then restored, the control circuit obtains the control signal of the circuit breaker before the power failure in the memory unit, and drives the mechanical switch and the power electronic device to operate respectively according to the control signal, thereby overcoming the defect of needing to reclose the circuit breaker from an external operation after power failure, and the operation is convenient.

[0030] Combination Figure 1-2A solid-state circuit breaker and a method for handling power failure thereof are provided. A solid-state circuit breaker includes a mechanical switch, a control circuit, a power electronic device and a power supply unit. The mechanical switch includes a contact mechanism and a control coil that drives the contact mechanism to operate. The contact mechanism includes a main contact and at least one auxiliary contact that operates synchronously with the main contact. One end of the main contact and one end of the power supply unit are connected to the input end of the circuit breaker. The power electronic device is connected in series on the main line between the other end of the main contact and the output end of the circuit breaker. The other end of the power supply unit is connected to the control circuit to supply power to the control circuit. The power supply unit is connected upstream of the mechanical switch and the power electronic device and will not be affected by the closing or disconnection of the mechanical switch and the power electronic device. The auxiliary contact is connected to the control circuit to feedback the operating state of the contact mechanism. The control coil is connected to the control circuit and operates the contact mechanism under the drive of the control circuit. The power electronic device is connected to the control circuit to drive the mechanical switch and the power electronic device to operate after the control circuit receives the control signal. Preferably, Figure 2 As shown, a current detection unit is also connected in series between the mechanical switch and the power electronic device. The current detection unit is connected to the control circuit and is used to transmit the current signal to the control circuit. The control circuit reads the current state of the circuit breaker line through the current detection unit, that is, whether an overload or short circuit occurs in the circuit of the circuit breaker, and performs protection processing when an overload or short circuit occurs, and shuts down the power electronic device and the mechanical switch.

[0031] When the control circuit is powered normally, the control circuit receives a control signal for controlling the opening and closing of the circuit breaker, and stores the control signal in a memory unit of the control circuit. The control circuit drives the mechanical switch and the power electronic device to operate according to the control signal.

[0032] After the power supply to the control circuit is interrupted and then restored to normal, the control circuit reads the control signal stored in the memory unit for the last time before the power failure. When the control signal read by the control circuit is a closing command, the control circuit drives the mechanical switch and the power electronic device to operate respectively; when the control signal read by the control circuit is an opening command, the control circuit does not drive the mechanical switch and the power electronic device to operate.

[0033] The control circuit includes a single-chip computer or a microprocessor MCU, which is connected to a control coil, a power electronic device and an auxiliary contact. The memory unit is a memory, which can be an EPROM or other storage unit. The memory unit is an independent memory, or a storage space built into the single-chip computer. When the control circuit is powered normally, it can be written into the memory unit through a human-machine interface or remotely. When the control circuit is powered on again after a power interruption, the control circuit first reads the data in the internal memory and then performs a corresponding operation. This operation can be a closing action or a maintaining of an opening state. The power electronic device can be a power electronic device switch such as an IGBT power tube, a MOSFET power tube, an NPN power tube, or a thyristor.

[0034] In practical applications, the normal power supply state of the control circuit includes two situations: always being in the normal power supply state and restoring the normal power supply after the power supply is interrupted. The working state of the solid-state circuit breaker includes the closed state and the open state. However, after the power supply of the control circuit is interrupted, the mechanical switch and the power electronic device will be in the open state.

[0035] When the control circuit is always in a normal power supply state and the solid-state circuit breaker is in an open state, when the control circuit obtains a closing command by receiving a control signal, the control circuit first drives the mechanical switch to close, and then drives the power electronic device to close; when the power supply of the control circuit is interrupted and restored to normal, and the solid-state circuit breaker is in an open state, when the control circuit obtains a closing command by reading a control signal stored in a memory unit, the control circuit first drives the mechanical switch to close, and then drives the power electronic device to close; when the power supply of the control circuit is interrupted and restored to normal, and the solid-state circuit breaker is in an open state, when the control circuit obtains an opening command by reading a control signal stored in a memory unit, the control circuit has no drive on the power electronic device and the mechanical switch, so that the mechanical switch and the power electronic device are in a disconnected state.

[0036] When the control circuit is always in a normal power supply state and the circuit breaker is in a closed state, when the control circuit obtains a trip command by receiving a control signal, the control circuit first drives the power electronic device to disconnect, and then drives the mechanical switch to disconnect.

[0037] In this embodiment, the mechanical switch is preferably as follows: Figure 1-2As shown, it includes main contacts and auxiliary contacts that act synchronously. The control circuit drives the contact mechanism of the mechanical switch to act synchronously through the control coil, but the main contacts and the auxiliary contacts will not reach the closed or disconnected state at the same time. When the control circuit drives the control coil to make the contact mechanism act, the main contact closes before the auxiliary contact. After the auxiliary contact is closed, the control circuit is fed back that the contact mechanism is in the closed state; when the control circuit drives the contact mechanism to disconnect, the auxiliary contact of the contact mechanism disconnects before the main contact. In this way, when the control circuit detects that the auxiliary contact is closed, the main contact must be in the closed state. When the control circuit detects that the auxiliary contact is in the disconnected state, the main contact must be in the process of disconnecting. At this time, the power electronic device is driven to close by the control circuit. Since the speed of the power electronic device is faster than that of the mechanical structure, the power electronic device can quickly shut down the main circuit. Compared with the existing solid-state circuit breaker that realizes the shutoff of the main line through mechanical switch action, the shutoff speed of this application is significantly faster.

[0038] A contact mechanism capable of realizing the above process is provided, wherein the main contact and the auxiliary contact have the same total stroke, the opening distance of the main contact is smaller than that of the auxiliary contact, and the overtravel of the main contact is larger than that of the auxiliary contact, so that when the contact mechanism is synchronously actuated, the main contact is closed before the auxiliary contact, and the auxiliary contact is opened before the main contact. For example, the main contact and the auxiliary contact are synchronously triggered, the opening distance of the main contact is 1 mm, the overtravel is 2 mm, and the total stroke is 3 mm, and the opening distance of the auxiliary contact is 2 mm, the overtravel is 1 mm, and the total stroke is 3 mm. During the closing process, when the main contact moves to 1mm, the main contact is closed. At this time, the auxiliary contact also moves 1mm, but the auxiliary contact is not closed yet. When the main contact and the auxiliary contact both move to the 2.1mm-3mm position, the main contact and the auxiliary contact are both closed, and the closing action is completed; when the auxiliary contact is closed, the main contact is also closed, and the closing action is completed; during the disconnection process, when the return distance of the main contact and the auxiliary contact is between 1.1-1.9mm, the auxiliary contact has been disconnected, and the main contact is in a closed state. When the return distance of the main contact and the auxiliary contact is at 2.1mm-3mm, the main contact and the auxiliary contact are both in a disconnected state. It should be noted that the overtravel, opening distance and total stroke length of the above-mentioned main contact and auxiliary contact are only examples, and the actual length needs to be designed according to needs.

[0039] In this embodiment, the control signal received and stored by the control circuit may come from a device connected to the control circuit for driving the control circuit, or may come from a solid-state circuit breaker. Figure 2As shown, a communication unit is connected to the control circuit, and the communication unit can enable an external host computer to input a control signal of opening and closing to the control circuit through a wired connection or a wireless connection. A software control unit can also be connected to the control circuit. In this embodiment, the software control unit is a human-machine interface, and the control signal of opening and closing is output to the control circuit by operating the human-machine interface. Of course, a hardware device can also be used to replace the human-machine interface, for example, a dial switch is used to replace the human-machine interface to send a control signal of opening and closing to the control circuit. In addition, the human-machine interface, the communication unit and the dial switch are also provided with fault protection functions such as overcurrent, short circuit, overvoltage and undervoltage, and also have a function of whether to reclose after power failure. When a short circuit or overload fault occurs in the solid-state circuit breaker, the short-circuit protection mechanism or overload protection mechanism of the solid-state circuit breaker sends a switch-off command to the control circuit, and the control circuit first drives the power electronic device to disconnect, and then drives the mechanical switch to disconnect.

[0040] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A solid-state circuit breaker, characterized in that: It comprises a mechanical switch, a control circuit, a power electronic device and a power supply unit. The mechanical switch comprises a contact mechanism and a control coil for driving the contact mechanism to move. The contact mechanism comprises a main contact and at least one auxiliary contact that moves synchronously with the main contact. One end of the main contact and one end of the power supply unit are connected to the input end of the circuit breaker. The power electronic device is connected in series to a main line between the other end of the main contact and the output end of the circuit breaker. The other end of the power supply unit is connected to the control circuit for supplying power to the control circuit. The auxiliary contact is connected to the control circuit for feeding back the action state of the contact mechanism. The control coil is connected to the control circuit and drives the contact mechanism to move under the drive of the control circuit. The power electronic device is connected to the control circuit and drives the mechanical switch and the power electronic device to move after the control circuit receives the control signal. The control circuit has a memory unit. After the power supply of the control circuit is interrupted and restored, the control circuit drives the mechanical switch and the power electronic device by reading the control signal before the power supply is interrupted in the memory unit.

2. A solid-state circuit breaker according to claim 1, characterized in that: The invention also includes a current detection unit, which is connected between the mechanical switch and the power electronic device, and is connected to the control circuit for transmitting a current signal to the control circuit.

3. A solid-state circuit breaker according to claim 1, characterized in that: The control circuit is also connected to a human-machine interface, and the human-machine interface is used to send a control signal for controlling the opening and closing of the circuit breaker to the control circuit.

4. A solid-state circuit breaker according to claim 1, characterized in that: The control circuit is also connected to a communication unit, which is connected to an external host computer. The communication unit is used to transmit a control signal generated by the host computer for controlling the opening and closing of the circuit breaker to the control circuit.

5. A solid-state circuit breaker according to claim 1, characterized in that: The control circuit is also connected to a dial switch, and the dial switch transmits a control signal for controlling the opening and closing of the circuit breaker to the control circuit.

6. A method for processing power failure of a solid-state circuit breaker, characterized in that: A solid-state circuit breaker according to any one of claims 1 to 5, wherein when the control circuit is powered normally, the control circuit receives a control signal for controlling the opening and closing of the circuit breaker, and stores the control signal in a memory unit of the control circuit, and the control circuit drives the mechanical switch and the power electronic device to operate according to the control signal; After the power supply to the control circuit is interrupted and then restored to normal, the control circuit reads the control signal stored in the memory unit for the last time before the power failure. When the control signal read by the control circuit is a closing command, the control circuit drives the mechanical switch and the power electronic device to operate respectively; when the control signal read by the control circuit is an opening command, the control circuit does not drive the mechanical switch and the power electronic device to operate.

7. A method for processing power failure of a solid-state circuit breaker according to claim 6, characterized in that: When the control circuit is powered normally and the solid-state circuit breaker is in the open state, after the control circuit obtains the closing command by receiving or reading the memory unit, the control circuit first drives the contact mechanism of the mechanical switch to close, and then drives the power electronic device to close; When the control circuit is powered normally and the solid-state circuit breaker is in the open state, after the control circuit obtains the opening command by reading the memory unit, the control circuit does not drive the power electronic device or the mechanical switch to operate; When the control circuit is powered normally and the solid-state circuit breaker is in the closed state, after the control circuit receives the opening command, the control circuit first drives the power electronic device to close and then drives the contact mechanism of the mechanical switch to open, and the auxiliary contact opens earlier than the main contact.

8. A method for processing power failure of a solid-state circuit breaker according to claim 7, characterized in that: When the control circuit drives the contact mechanism to close, the main contact of the contact mechanism closes before the auxiliary contact, and after the auxiliary contact closes, it feeds back to the control circuit that the contact mechanism is in a closed state; When the control circuit drives the contact mechanism to open, the auxiliary contacts of the contact mechanism open before the main contacts.

9. A method for processing power failure of a solid-state circuit breaker according to claim 6 or 7, characterized in that: The control signal received and stored by the control circuit includes a closing command, which may come from a human-machine interface connected to the control circuit, or the closing command may be transmitted by a communication unit connected to the control circuit, or the closing command may come from a dial switch connected to the control circuit.

10. A method for processing power failure of a solid-state circuit breaker according to claim 6 or 7, characterized in that: The control signal received and stored by the control circuit includes a trip command, which may come from a human-machine interface connected to the control circuit, or the trip command may be transmitted by a communication unit connected to the control circuit, or the trip command may come from a dip switch connected to the control circuit, or the trip command may come from a short-circuit protection mechanism or an overload protection mechanism of a solid-state circuit breaker.

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