Rapid discharging method for direct current side of converter

Abstract

The invention relates to a direct-current side rapid discharging technology, and discloses a converter direct-current side rapid discharging method, which comprises the following steps of: during boosting, monitoring a voltage value of a direct-current side capacitor in real time, comparing the voltage value with a preset target voltage, and when the detected capacitor voltage is lower than a set value, adjusting the output of a power supply circuit and increasing a charging current by a control system; on the contrary, when the voltage of the capacitor is close to the set value, the control system can gradually reduce the charging current, so that stable boosting is achieved, and voltage overshoot is avoided. According to the converter direct-current side rapid discharging method, the circuit can be actively disconnected, so that the influence on a power grid is cut off, the problem of direct-current side capacitor discharging existing in an existing APF or SVG hardware power topology is solved, and the converter direct-current side rapid discharging method has very high practical value, so that under the condition that the cost is not increased too much, the direct-current side rapid discharging of the converter is achieved through a local inversion method. And the voltage of the direct current side capacitor can be rapidly reduced, so that the safety of maintenance personnel is protected, and the practicability is very high.

Description

Technical Field

[0001] The invention relates to the technical field of DC side rapid discharge, and in particular to a method for rapid discharge of a DC side of a converter. Background Art

[0002] With the development of the national economy, the number of electrical equipment is increasing, and the harmonics and reactive components in the power system are also increasing. This will not only pollute the power grid, but also lead to instability of electrical equipment. In a three-phase power grid, the DC side capacitor will have a relatively high rectified voltage under the action of the three-phase rectifier bridge. When maintenance personnel shut down the equipment, disconnect the power grid, and maintain the equipment, the DC side capacitor has no discharge device, which causes its voltage to be relatively high, posing a great safety hazard to maintenance personnel. Therefore, it is necessary to effectively discharge the DC side capacitor.

[0003] In addition, the commonly used discharge methods for DC side capacitors on the market now include natural discharge, discharge with a large resistance discharge resistor, and relay-added discharge resistor. Among them, the natural discharge speed is very slow, and it takes about half an hour or more to discharge. The discharge with a large resistance discharge resistor also takes more than 15 minutes. The relay adds a discharge resistor to discharge. Due to the relatively high DC side voltage, the requirements for relays are relatively strict, which increases the economic cost. In addition, a discharge resistor is also required, which invisibly increases the size of the equipment. In addition, there is a problem of DC side capacitor discharge in the existing APF or SVG hardware power topology. Therefore, it is necessary to design a DC side fast discharge method for the converter. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies in the prior art, the present invention provides a method for quickly discharging the DC side of a converter, which has the advantages of quickly reducing the voltage of the DC side capacitor and solves the safety problem caused by the high voltage on the DC side.

[0006] (II) Technical solution

[0007] In order to achieve the above-mentioned purpose of rapidly reducing the voltage problem of the DC side capacitor, the present invention provides the following technical solution: a method for rapidly discharging the DC side of a converter, comprising the following steps:

[0008] S1, the DC side capacitor inside the power grid is boosted to the set voltage value

[0009] When boosting, the voltage value of the DC side capacitor is monitored in real time and compared with the preset target voltage. When it is detected that the capacitor voltage is lower than the set value, the control system will adjust the output of the power circuit, increase the charging current, and speed up the charging speed of the capacitor. Conversely, when the capacitor voltage approaches the set value, the control system will gradually reduce the charging current to achieve a smooth boost and avoid voltage overshoot.

[0010] S2, close relay Breaker1 and allow the device capacitor to charge through the Breaker's soft-start resistor and rectifier bridge

[0011] In the current electrical system operation, the first task is to close the relay Breaker1. This operation will trigger a series of key electrical processes, the most important of which is to create conditions for the charging of the device capacitor. The charging process of the device capacitor needs to be completed through the Breaker's soft-start resistor and the rectifier bridge. The soft-start resistor limits the initial charging current in this process to avoid damage to the device caused by excessive current, ensuring the smoothness and safety of the charging process, while the rectifier bridge is responsible for converting AC power into DC power to provide a suitable charging power source for the device capacitor.

[0012] S3, after the capacitor is charged stably, close the relay Breaker and perform high current output compensation

[0013] Pay close attention to the charging status of the capacitor during the charging process. The charging progress of the capacitor can be understood by observing the voltmeter connected to both ends of the capacitor and the ammeter connected in series in the circuit. As time goes by, the reading of the voltmeter will gradually increase, and the reading of the ammeter will gradually decrease. When the reading of the voltmeter stabilizes at a fixed value and the reading of the ammeter approaches zero, it indicates that the capacitor charging has stabilized.

[0014] Next, find the control switch of the relay breaker. This switch is usually located in the electrical control cabinet. There may be a clear mark next to it. Before operating, you need to confirm again that the capacitor charging has been stable and the surrounding environment is safe without any potential electrical hazards. Then, slowly and steadily turn the control switch of the relay breaker to the closed position;

[0015] After the relay breaker is successfully closed, the system will automatically start the high current output compensation procedure. During this process, the ammeter reading rises rapidly, indicating that the system is outputting a large current to meet the special needs of the load. At this time, pay close attention to the readings of the ammeter and other related instruments to ensure that the high current output compensation process proceeds smoothly and that all parameters are within the normal range.

[0016] S4, disconnect Breaker1 and discharge the DC side capacitor by turning on PWM

[0017] When the equipment is shut down, the PWM pulse is blocked and Breaker1 is disconnected. The PWM is turned on to perform inverter discharge on the DC side capacitor. During the operation of the equipment, the PWM pulse adjusts the frequency and amplitude of the output signal by controlling the pulse width, and accurately controls various operating parameters of the equipment. When the equipment needs to be shut down, the PWM pulse is blocked to cut off the control signal source, so that the related circuits of the equipment lose the pulse drive and gradually stop running. After blocking the PWM pulse, Breaker1 is disconnected in time.

[0018] After completing the above two steps, the next step is to enter the inverter discharge link of the DC side capacitor. The inverter discharge operation of the DC side capacitor is realized by turning on PWM, an effective control method. The PWM technology can accurately control the on and off time of the power switch device, so as to convert the electric energy stored in the DC side capacitor into AC electric energy in a specific way and release it. In this inverter discharge process, it is necessary to continuously monitor the voltage value of the DC side capacitor. As the discharge continues, the voltage of the DC side capacitor will gradually decrease until it reaches the safety voltage standard. Once the voltage of the DC side capacitor reaches the preset safety voltage value, the discharge operation must be stopped in time to ensure the safety and stability of the entire system and avoid equipment damage or other safety hazards caused by excessive discharge.

[0019] S5: Stop discharging and disconnect the Breaker operation after the DC side capacitor reaches the safety voltage

[0020] The voltage across the DC capacitor is monitored in real time through a high-precision voltage sensor. When the DC capacitor reaches a safe voltage, the control system will immediately issue a command to stop discharging and instruct the relay to operate. The relay disconnects the contacts through electromagnetic force, thereby cutting off the discharge circuit. The electronic switch uses the conduction and cutoff characteristics of semiconductor devices to quickly interrupt the current. After the discharge stop operation is completed, the control system will issue a trip command to the circuit breaker. After receiving the command, the operating mechanism inside the circuit breaker separates the contacts of the circuit breaker through mechanical or electromagnetic devices. At the moment the contacts separate, an arc will be generated. In order to extinguish the arc, DC circuit breakers usually use special arc extinguishing devices, such as magnetic arc extinguishing, gas arc extinguishing, etc.

[0021] Preferably, in step S1, during the boost process, the control system will monitor the voltage value of the capacitor in real time and compare it with the set value. If the actual voltage is lower than the set value, the control system will instruct the converter to increase the output power, thereby gradually increasing the voltage of the capacitor. This process requires precise control algorithms and fast response mechanisms to ensure that the voltage can reach the set value smoothly and quickly, while avoiding the occurrence of unsafe situations such as overvoltage or overcurrent.

[0022] Preferably, in step S2, during the charging process, the current will pass through a rectifier bridge, the function of which is to convert alternating current into direct current to ensure that the capacitor can be charged stably. The rectifier bridge is usually composed of multiple diodes, which are connected in a specific way to achieve unidirectional flow of current.

[0023] Preferably, in step S3, the voltage and current of the capacitor and other key parameters of the system should be continuously monitored. Once an abnormality or fault is found, protective measures should be taken immediately, such as disconnecting the relay, reducing the output voltage, etc., to avoid damage to the system and equipment.

[0024] Preferably, in step S4, Breaker1, as a key switching element in the circuit, is responsible for controlling the on and off of the circuit. Disconnecting Breaker1 in time can further ensure that the circuit is in an open circuit state, preventing the current from continuing to flow disorderly after the equipment is shut down, thereby avoiding possible electrical safety hazards such as short circuit, overload, etc.

[0025] Preferably, in step S5, when the voltage of the DC side capacitor gradually decreases until it reaches a safe voltage, stopping the discharge operation is an inevitable requirement to ensure that the entire system is in a stable and safe state, because if the discharge continues, the capacitor voltage may be too low, which may not only affect the normal operation of other devices connected to it, but also may damage the performance and life of the capacitor itself.

[0026] Preferably, in step S5, Breaker serves as a protection and control element in the circuit, and disconnecting it can effectively cut off the circuit connection. This can prevent the current from flowing back into the DC side capacitor that has stopped discharging due to certain unexpected factors, such as interference signals in the circuit, misoperation of other equipment, etc. during the subsequent system operation, thereby avoiding possible overcharging or other abnormal conditions, thereby further ensuring the safety and reliability of the entire circuit system.

[0027] Preferably, in step S5, in the process of disconnecting the circuit breaker, the inductance element in the circuit also needs to be taken into consideration. When the current is suddenly interrupted, the inductance will generate a back electromotive force, which may cause an overvoltage. In order to suppress this overvoltage, some protection elements are usually connected in parallel at both ends of the circuit breaker, such as metal oxide arresters or resistor-capacitor absorption devices. These protection elements can be quickly turned on when an overvoltage occurs, limiting the overvoltage within a certain range, thereby protecting the safety of the equipment.

[0028] (III) Beneficial effects

[0029] Compared with the prior art, the present invention provides a method for fast discharging of the DC side of a converter, which has the following beneficial effects:

[0030] 1. The DC side fast discharge method of the converter can reduce the DC side capacitor voltage to a safe voltage without increasing power consumption through the APF or SVG DC side capacitor fast discharge method, thereby solving the safety problem caused by the high DC side voltage. In addition, in the event of equipment failure, the circuit can be actively disconnected to cut off the impact on the power grid, solving the DC side capacitor discharge problem existing in the existing APF or SVG hardware power topology, and having high practical value. Therefore, without increasing too much cost, the DC side capacitor voltage can be quickly reduced through the local inversion method, thereby protecting the safety of maintenance personnel, and having high practicality.

[0031] 2. The fast discharge method of the DC side of the converter, by turning on PWM, uses the inverter circuit to convert the DC power stored in the DC side capacitor into AC power, and releases it to the external circuit. This process can not only safely and effectively consume the remaining electric energy in the capacitor, but also ensure that the DC side capacitor is in a safe low-power state before the next startup of the equipment, creating good conditions for the normal operation of the equipment again. The entire operation process is closely linked and interlocking, aiming to ensure the safety, reliability and overall performance of the equipment during the shutdown process. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Embodiment 1:

[0035] A method for rapidly discharging a DC side of a converter comprises the following steps:

[0036] S1, the DC side capacitor inside the power grid is boosted to the set voltage value

[0037] When boosting, the voltage value of the DC side capacitor is monitored in real time and compared with the preset target voltage. When it is detected that the capacitor voltage is lower than the set value, the control system will adjust the output of the power circuit, increase the charging current, and speed up the charging speed of the capacitor. Conversely, when the capacitor voltage approaches the set value, the control system will gradually reduce the charging current to achieve a smooth boost and avoid voltage overshoot.

[0038] S2, close relay Breaker1 and allow the device capacitor to charge through the Breaker's soft-start resistor and rectifier bridge

[0039] In the current electrical system operation, the first task is to close the relay Breaker1. This operation will trigger a series of key electrical processes, the most important of which is to create conditions for the charging of the device capacitor. The charging process of the device capacitor needs to be completed through the Breaker's soft-start resistor and the rectifier bridge. The soft-start resistor limits the initial charging current in this process to avoid damage to the device caused by excessive current, ensuring the smoothness and safety of the charging process, while the rectifier bridge is responsible for converting AC power into DC power to provide a suitable charging power source for the device capacitor.

[0040] S3, after the capacitor is charged stably, close the relay Breaker and perform high current output compensation

[0041] Pay close attention to the charging status of the capacitor during the charging process. The charging progress of the capacitor can be understood by observing the voltmeter connected to both ends of the capacitor and the ammeter connected in series in the circuit. As time goes by, the reading of the voltmeter will gradually increase, and the reading of the ammeter will gradually decrease. When the reading of the voltmeter stabilizes at a fixed value and the reading of the ammeter approaches zero, it indicates that the capacitor charging has stabilized.

[0042] Next, find the control switch of the relay breaker. This switch is usually located in the electrical control cabinet. There may be a clear mark next to it. Before operating, you need to confirm again that the capacitor charging has been stable and the surrounding environment is safe without any potential electrical hazards. Then, slowly and steadily turn the control switch of the relay breaker to the closed position;

[0043] After the relay breaker is successfully closed, the system will automatically start the high current output compensation procedure. During this process, the ammeter reading rises rapidly, indicating that the system is outputting a large current to meet the special needs of the load. At this time, pay close attention to the readings of the ammeter and other related instruments to ensure that the high current output compensation process proceeds smoothly and that all parameters are within the normal range.

[0044] S4, disconnect Breaker1 and discharge the DC side capacitor by turning on PWM

[0045] When the equipment is shut down, the PWM pulse is blocked and Breaker1 is disconnected. The PWM is turned on to perform inverter discharge on the DC side capacitor. During the operation of the equipment, the PWM pulse adjusts the frequency and amplitude of the output signal by controlling the pulse width, and accurately controls various operating parameters of the equipment. When the equipment needs to be shut down, the PWM pulse is blocked to cut off the control signal source, so that the related circuits of the equipment lose the pulse drive and gradually stop running. After blocking the PWM pulse, Breaker1 is disconnected in time.

[0046] After completing the above two steps, the next step is to enter the inverter discharge link of the DC side capacitor. The inverter discharge operation of the DC side capacitor is realized by turning on PWM, an effective control method. The PWM technology can accurately control the on and off time of the power switch device, so as to convert the electric energy stored in the DC side capacitor into AC electric energy in a specific way and release it. In this inverter discharge process, it is necessary to continuously monitor the voltage value of the DC side capacitor. As the discharge continues, the voltage of the DC side capacitor will gradually decrease until it reaches the safety voltage standard. Once the voltage of the DC side capacitor reaches the preset safety voltage value, the discharge operation must be stopped in time to ensure the safety and stability of the entire system and avoid equipment damage or other safety hazards caused by excessive discharge.

[0047] S5: Stop discharging and disconnect the Breaker operation after the DC side capacitor reaches the safety voltage

[0048] The voltage across the DC capacitor is monitored in real time through a high-precision voltage sensor. When the DC capacitor reaches a safe voltage, the control system will immediately issue a command to stop discharging and instruct the relay to operate. The relay disconnects the contacts through electromagnetic force, thereby cutting off the discharge circuit. The electronic switch uses the conduction and cutoff characteristics of semiconductor devices to quickly interrupt the current. After the discharge stop operation is completed, the control system will issue a trip command to the circuit breaker. After receiving the command, the operating mechanism inside the circuit breaker separates the contacts of the circuit breaker through mechanical or electromagnetic devices. At the moment the contacts separate, an arc will be generated. In order to extinguish the arc, DC circuit breakers usually use special arc extinguishing devices, such as magnetic arc extinguishing, gas arc extinguishing, etc.

[0049] Embodiment 2:

[0050] A method for rapidly discharging a DC side of a converter comprises the following steps:

[0051] S1, the DC side capacitor inside the power grid is boosted to the set voltage value

[0052] When boosting, the voltage value of the DC side capacitor is monitored in real time and compared with the preset target voltage. When it is detected that the capacitor voltage is lower than the set value, the control system will adjust the output of the power circuit, increase the charging current, and speed up the charging speed of the capacitor. Conversely, when the capacitor voltage approaches the set value, the control system will gradually reduce the charging current to achieve a smooth boost and avoid voltage overshoot.

[0053] S2, close relay Breaker1 and allow the device capacitor to charge through the Breaker's soft-start resistor and rectifier bridge

[0054] In the current electrical system operation, the first task is to close the relay Breaker1. This operation will trigger a series of key electrical processes, the most important of which is to create conditions for the charging of the device capacitor. The charging process of the device capacitor needs to be completed through the Breaker's soft-start resistor and the rectifier bridge. The soft-start resistor limits the initial charging current in this process to avoid damage to the device caused by excessive current, ensuring the smoothness and safety of the charging process, while the rectifier bridge is responsible for converting AC power into DC power to provide a suitable charging power source for the device capacitor.

[0055] S3, after the capacitor is charged stably, close the relay Breaker and perform high current output compensation

[0056] Pay close attention to the charging status of the capacitor during the charging process. The charging progress of the capacitor can be understood by observing the voltmeter connected to both ends of the capacitor and the ammeter connected in series in the circuit. As time goes by, the reading of the voltmeter will gradually increase, and the reading of the ammeter will gradually decrease. When the reading of the voltmeter stabilizes at a fixed value and the reading of the ammeter approaches zero, it indicates that the capacitor charging has stabilized.

[0057] Next, find the control switch of the relay breaker. This switch is usually located in the electrical control cabinet. There may be a clear mark next to it. Before operating, you need to confirm again that the capacitor charging has been stable and the surrounding environment is safe without any potential electrical hazards. Then, slowly and steadily turn the control switch of the relay breaker to the closed position;

[0058] After the relay breaker is successfully closed, the system will automatically start the high current output compensation procedure. During this process, the ammeter reading rises rapidly, indicating that the system is outputting a large current to meet the special needs of the load. At this time, pay close attention to the readings of the ammeter and other related instruments to ensure that the high current output compensation process proceeds smoothly and that all parameters are within the normal range.

[0059] S4, disconnect Breaker1 and discharge the DC side capacitor by turning on PWM

[0060] When the equipment is shut down, the PWM pulse is blocked and Breaker1 is disconnected. The PWM is turned on to perform inverter discharge on the DC side capacitor. During the operation of the equipment, the PWM pulse adjusts the frequency and amplitude of the output signal by controlling the pulse width, and accurately controls various operating parameters of the equipment. When the equipment needs to be shut down, the PWM pulse is blocked to cut off the control signal source, so that the related circuits of the equipment lose the pulse drive and gradually stop running. After blocking the PWM pulse, Breaker1 is disconnected in time.

[0061] After completing the above two steps, the next step is to enter the inverter discharge link of the DC side capacitor. The inverter discharge operation of the DC side capacitor is realized by turning on PWM, an effective control method. The PWM technology can accurately control the on and off time of the power switch device, so as to convert the electric energy stored in the DC side capacitor into AC electric energy in a specific way and release it. In this inverter discharge process, it is necessary to continuously monitor the voltage value of the DC side capacitor. As the discharge continues, the voltage of the DC side capacitor will gradually decrease until it reaches the safety voltage standard. Once the voltage of the DC side capacitor reaches the preset safety voltage value, the discharge operation must be stopped in time to ensure the safety and stability of the entire system and avoid equipment damage or other safety hazards caused by excessive discharge.

[0062] S5: Stop discharging and disconnect the Breaker operation after the DC side capacitor reaches the safety voltage

[0063] The voltage across the DC capacitor is monitored in real time by a high-precision voltage sensor. When the DC capacitor reaches a safe voltage, the control system will immediately issue a command to stop discharging and command the relay to operate. The relay disconnects the contacts through electromagnetic force, thereby cutting off the discharge circuit. The electronic switch uses the conduction and cutoff characteristics of semiconductor devices to quickly interrupt the current. After the discharge stop operation is completed, the control system will issue a trip command to the circuit breaker. After receiving the command, the operating mechanism inside the circuit breaker separates the contacts of the circuit breaker through mechanical or electromagnetic devices. At the moment when the contacts are separated, an arc will be generated. In order to extinguish the arc, DC circuit breakers usually use special arc extinguishing devices, such as magnetic arc extinguishing, gas arc extinguishing, etc.

[0064] Specifically, in step S1, during the boost process, the control system will monitor the voltage value of the capacitor in real time and compare it with the set value. If the actual voltage is lower than the set value, the control system will instruct the converter to increase the output power, thereby gradually increasing the voltage of the capacitor. This process requires precise control algorithms and fast response mechanisms to ensure that the voltage can reach the set value smoothly and quickly, while avoiding unsafe situations such as overvoltage or overcurrent.

[0065] Specifically, in step S2, during the charging process, the current will pass through a rectifier bridge, which converts AC power into DC power to ensure that the capacitor can be stably charged. The rectifier bridge is usually composed of multiple diodes, which are connected in a specific way to achieve unidirectional current flow;

[0066] Specifically, in step S3, the voltage and current of the capacitor and other key parameters of the system should be continuously monitored. Once an abnormality or failure is found, protective measures should be taken immediately, such as disconnecting the relay, reducing the output voltage, etc., to avoid damage to the system and equipment;

[0067] Specifically, in step S4, Breaker1, as a key switch element in the circuit, is responsible for controlling the on and off of the circuit. Disconnecting Breaker1 in time can further ensure that the circuit is in an open circuit state, preventing the current from continuing to flow disorderly after the equipment is shut down, thereby avoiding possible electrical safety hazards, such as short circuit, overload, etc.;

[0068] Specifically, in step S5, when the voltage of the DC side capacitor gradually decreases until it reaches a safe voltage, stopping the discharge operation is an inevitable requirement to ensure that the entire system is in a stable and safe state, because if the discharge continues, the capacitor voltage may be too low, which may not only affect the normal operation of other devices connected to it, but also may damage the performance and life of the capacitor itself;

[0069] Specifically, in step S5, Breaker is a protection and control element in the circuit. Disconnecting it can effectively cut off the circuit connection. This can prevent the current from flowing back into the DC side capacitor that has stopped discharging due to some unexpected factors such as interference signals in the circuit, misoperation of other equipment, etc. during the subsequent system operation, thereby avoiding possible overcharging or other abnormal conditions, thereby further ensuring the safety and reliability of the entire circuit system.

[0070] Specifically, in step S5, when disconnecting the circuit breaker, the inductor components in the circuit also need to be considered. When the current is suddenly interrupted, the inductor will generate a back electromotive force, which may cause overvoltage. In order to suppress this overvoltage, some protection components are usually connected in parallel at both ends of the circuit breaker, such as metal oxide arresters or resistor-capacitor absorption devices. These protection components can be quickly turned on when overvoltage occurs, limit the overvoltage to a certain range, and protect the safety of the equipment.

[0071] During operation, first close relay Breaker1, and the device capacitor is charged through the soft-start resistor and rectifier bridge of Breaker. After reaching steady state, close Breaker again to compensate for large current output. When the device is shut down, first block the PWM pulse, then disconnect Breaker1, and then turn on PWM to perform inverter discharge on the DC side capacitor. When the DC side capacitor reaches a safe voltage, the discharge stops, and finally disconnect Breaker to complete the shutdown action.

[0072] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for rapid discharge of a DC side of a converter, characterized in that: The following steps are involved: S1, the DC side capacitor inside the power grid is boosted to the set voltage value When boosting, the voltage value of the DC side capacitor is monitored in real time and compared with the preset target voltage. When it is detected that the capacitor voltage is lower than the set value, the control system will adjust the output of the power circuit, increase the charging current, and speed up the charging speed of the capacitor. Conversely, when the capacitor voltage approaches the set value, the control system will gradually reduce the charging current to achieve a smooth boost and avoid voltage overshoot. S2, close relay Breaker1 and allow the device capacitor to charge through the Breaker's soft-start resistor and rectifier bridge In the current electrical system operation, the first task is to close the relay Breaker1. This operation will trigger a series of key electrical processes, the most important of which is to create conditions for the charging of the device capacitor. The charging process of the device capacitor needs to be completed through the Breaker's soft-start resistor and the rectifier bridge. The soft-start resistor limits the initial charging current in this process to avoid damage to the device caused by excessive current, ensuring the smoothness and safety of the charging process, while the rectifier bridge is responsible for converting AC power into DC power to provide a suitable charging power source for the device capacitor. S3, after the capacitor is charged stably, close the relay Breaker and perform high current output compensation Pay close attention to the charging status of the capacitor during the charging process. The charging progress of the capacitor can be understood by observing the voltmeter connected to both ends of the capacitor and the ammeter connected in series in the circuit. As time goes by, the reading of the voltmeter will gradually increase, and the reading of the ammeter will gradually decrease. When the reading of the voltmeter stabilizes at a fixed value and the reading of the ammeter approaches zero, it indicates that the capacitor charging has stabilized. Next, find the control switch of the relay breaker. This switch is usually located in the electrical control cabinet. There may be a clear mark next to it. Before operating, you need to confirm again that the capacitor charging has been stable and the surrounding environment is safe without any potential electrical hazards. Then, slowly and steadily turn the control switch of the relay breaker to the closed position; After the relay breaker is successfully closed, the system will automatically start the high current output compensation procedure. During this process, the ammeter reading rises rapidly, indicating that the system is outputting a large current to meet the special needs of the load. At this time, pay close attention to the readings of the ammeter and other related instruments to ensure that the high current output compensation process proceeds smoothly and that all parameters are within the normal range. S4, disconnect Breaker1 and discharge the DC side capacitor by turning on PWM When the equipment is shut down, the PWM pulse is blocked and Breaker1 is disconnected. The PWM is turned on to perform inverter discharge on the DC side capacitor. During the operation of the equipment, the PWM pulse adjusts the frequency and amplitude of the output signal by controlling the pulse width, and accurately controls various operating parameters of the equipment. When the equipment needs to be shut down, the PWM pulse is blocked to cut off the control signal source, so that the related circuits of the equipment lose the pulse drive and gradually stop running. After blocking the PWM pulse, Breaker1 is disconnected in time. After completing the above two steps, the next step is to enter the inverter discharge link of the DC side capacitor. The inverter discharge operation of the DC side capacitor is realized by turning on PWM, an effective control method. The PWM technology can accurately control the on and off time of the power switch device, so as to convert the electric energy stored in the DC side capacitor into AC electric energy in a specific way and release it. In this inverter discharge process, it is necessary to continuously monitor the voltage value of the DC side capacitor. As the discharge continues, the voltage of the DC side capacitor will gradually decrease until it reaches the safety voltage standard. Once the voltage of the DC side capacitor reaches the preset safety voltage value, the discharge operation must be stopped in time to ensure the safety and stability of the entire system and avoid equipment damage or other safety hazards caused by excessive discharge. S5: Stop discharging and disconnect the Breaker operation after the DC side capacitor reaches the safety voltage The voltage across the DC capacitor is monitored in real time through a high-precision voltage sensor. When the DC capacitor reaches a safe voltage, the control system will immediately issue a command to stop discharging and instruct the relay to operate. The relay disconnects the contacts through electromagnetic force, thereby cutting off the discharge circuit. The electronic switch uses the conduction and cutoff characteristics of semiconductor devices to quickly interrupt the current. After the discharge stop operation is completed, the control system will issue a trip command to the circuit breaker. After receiving the command, the operating mechanism inside the circuit breaker separates the contacts of the circuit breaker through mechanical or electromagnetic devices. At the moment the contacts separate, an arc will be generated. In order to extinguish the arc, DC circuit breakers usually use special arc extinguishing devices, such as magnetic arc extinguishing, gas arc extinguishing, etc.

2. A method for rapid discharge of a DC side of a converter according to claim 1, characterized in that: In step S1, during the boost process, the control system will monitor the voltage value of the capacitor in real time and compare it with the set value. If the actual voltage is lower than the set value, the control system will instruct the converter to increase the output power, thereby gradually increasing the voltage of the capacitor. This process requires precise control algorithms and fast response mechanisms to ensure that the voltage can reach the set value smoothly and quickly, while avoiding unsafe situations such as overvoltage or overcurrent.

3. A method for rapid discharge of a DC side of a converter according to claim 1, characterized in that: In step S2, during the charging process, the current will pass through a rectifier bridge, which converts alternating current into direct current to ensure that the capacitor can be stably charged. The rectifier bridge is usually composed of multiple diodes, which are connected in a specific way to achieve unidirectional flow of current.

4. A method for rapid discharge of a DC side of a converter according to claim 1, characterized in that: In step S3, the voltage and current of the capacitor and other key parameters of the system should be continuously monitored. Once an abnormality or fault is found, protective measures should be taken immediately, such as disconnecting the relay, reducing the output voltage, etc., to avoid damage to the system and equipment.

5. A method for rapid discharge of a DC side of a converter according to claim 1, characterized in that: In step S4, Breaker1, as a key switch element in the circuit, is responsible for controlling the on and off of the circuit. Disconnecting Breaker1 in time can further ensure that the circuit is in an open circuit state, preventing the current from continuing to flow disorderly after the equipment is shut down, thereby avoiding possible electrical safety hazards such as short circuit, overload, etc.

6. A method for rapid discharge of a DC side of a converter according to claim 1, characterized in that: In step S5, when the voltage of the DC side capacitor gradually decreases until it reaches a safe voltage, stopping the discharge operation is an inevitable requirement to ensure that the entire system is in a stable and safe state. If the discharge continues, the capacitor voltage may be too low, which may not only affect the normal operation of other devices connected to it, but also may damage the performance and life of the capacitor itself.

7. A method for rapid discharge of a DC side of a converter according to claim 1, characterized in that: In step S5, Breaker acts as a protection and control element in the circuit. Disconnecting it can effectively cut off the circuit connection. This can prevent the current from flowing back into the DC side capacitor that has stopped discharging due to certain unexpected factors such as interference signals in the circuit, misoperation of other equipment, etc. during the subsequent system operation, thereby avoiding possible overcharging or other abnormal conditions, thereby further ensuring the safety and reliability of the entire circuit system.

8. A method for rapid discharge of a DC side of a converter according to claim 1, characterized in that: In step S5, when disconnecting the circuit breaker, the inductance element in the circuit also needs to be considered. When the current is suddenly interrupted, the inductance will generate a back electromotive force, which may cause overvoltage. In order to suppress this overvoltage, some protection elements are usually connected in parallel at both ends of the circuit breaker, such as metal oxide arresters or resistor-capacitor absorption devices. These protection elements can be quickly turned on when overvoltage occurs, limit the overvoltage to a certain range, and protect the safety of the equipment.

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