CN118523602A - High-voltage precharge control method for power unit cascade frequency converter - Google Patents
High-voltage precharge control method for power unit cascade frequency converter Download PDFInfo
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- CN118523602A CN118523602A CN202410618465.7A CN202410618465A CN118523602A CN 118523602 A CN118523602 A CN 118523602A CN 202410618465 A CN202410618465 A CN 202410618465A CN 118523602 A CN118523602 A CN 118523602A
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- 238000000034 method Methods 0.000 title claims abstract description 31
- 238000010586 diagram Methods 0.000 description 11
- 238000004891 communication Methods 0.000 description 7
- 230000006870 function Effects 0.000 description 7
- 238000004590 computer program Methods 0.000 description 5
- 238000012986 modification Methods 0.000 description 2
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- 239000013307 optical fiber Substances 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
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- 238000001514 detection method Methods 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0006—Arrangements for supplying an adequate voltage to the control circuit of converters
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
Abstract
The invention relates to the technical field of frequency converter precharge control, and discloses a high-voltage precharge control method for a power unit cascade frequency converter. After a power supply in the frequency converter is started, determining whether to precharge the frequency converter or not according to the system state and the state of each power unit by utilizing a programmable logic controller in the frequency converter; when the high-voltage outlet cabinet circuit breaker is allowed to be switched on after the precharge is started, a programmable logic controller in a frequency converter is used for controlling a first intermediate relay in a switching-on control loop of the vacuum circuit breaker in the high-voltage outlet cabinet to be switched on, so that the switching-on of the high-voltage outlet cabinet circuit breaker is completed; and (3) controlling the disconnection of a pre-charging vacuum contactor connected into the outlet cabinet by using a normally closed auxiliary contact of the high-voltage outlet cabinet circuit breaker, so as to complete high-voltage pre-charging. The invention avoids the expansion of faults and even damage to the frying machine caused by faults found in the pre-charging process of the frequency converter, and improves the quality and reliability of the frequency converter.
Description
Technical Field
The invention relates to the technical field of frequency converter precharge control, in particular to a high-voltage precharge control method for a power unit cascade frequency converter.
Background
The frequency converter pre-charging mode mainly comprises three modes: the high-voltage side is precharged, the low-voltage side is precharged and a special precharge device is arranged, the first two types of the precharge devices are basically used for precharging the frequency converter through a pre-stage transformer, and the 3rd type of the precharge device is used for precharging the frequency converter, such as a step-up transformer, a current-limiting resistor, a rectifying module, an auxiliary control loop and the like. The traditional pre-charging mode is basically that once the pre-charging starting bus voltage reaches the target voltage, the main power is directly switched on to send the main power, the main power is disconnected after the main power is powered on in one step after the main power is failed, the PLC and the main board controller cannot timely terminate the main power to power on even if the main power detects and reports the failure in the pre-charging process, and the main power does not have a current limiting resistor, so that the frequency converter is possibly expanded in failure, and the frequency converter is damaged or even fried.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a high-voltage precharge control method for a power unit cascade frequency converter.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
A high-voltage precharge control method for a power unit cascade frequency converter comprises the following steps:
After the power supply in the frequency converter is started, determining whether to allow the frequency converter to be precharged or not according to the system state and the state of each power unit by utilizing a programmable logic controller in the frequency converter;
when the frequency converter is allowed to be precharged, a programmable logic controller in the frequency converter is used for controlling a first intermediate relay in a switching-on control loop of a vacuum circuit breaker in the high-voltage outlet cabinet to be closed, so that switching-on of the circuit breaker of the high-voltage outlet cabinet is completed;
and (3) controlling the disconnection of a pre-charging vacuum contactor connected into the outlet cabinet by using a normally closed auxiliary contact of the high-voltage outlet cabinet circuit breaker, so as to complete high-voltage pre-charging.
Preferably, determining whether to allow pre-charging of the frequency converter based on the system state and the state of each power cell using a programmable logic controller within the frequency converter comprises the steps of:
comparing the acquired signals of the current sensor and the voltage sensor with corresponding set thresholds by utilizing a programmable logic controller in the frequency converter according to the digital input signal state; if the set threshold value is exceeded, the frequency converter fails; otherwise, the frequency converter has no fault;
detecting whether a heartbeat signal sent by a main board controller is received or not by using a programmable logic controller in the frequency converter; if yes, the frequency converter has no fault; otherwise, the frequency converter fails;
detecting whether a feedback signal sent by a power unit is received or not by using a main board controller in the frequency converter; if yes, the frequency converter has no fault; otherwise, the frequency converter fails;
When the frequency converter has no fault, comparing the voltage value of the direct current bus with a set voltage target value by utilizing a programmable logic controller in the frequency converter; if the voltage value of the direct current bus reaches the set voltage target value, allowing the high-voltage outlet cabinet circuit breaker to be switched on; otherwise, the high-voltage outlet cabinet circuit breaker is not allowed to be switched on.
Preferably, the method further comprises the following steps:
When the frequency converter fails, a programmable logic controller in the frequency converter is utilized to control the second intermediate relay in the switching-off control loop of the high-voltage outlet cabinet circuit breaker to be attracted.
Preferably, the auxiliary contact string of the second intermediate relay is connected into a switching control loop of the high-voltage outlet cabinet circuit breaker and the pre-charging vacuum contactor.
Preferably, the method further comprises the following steps:
when the frequency converter is not allowed to be precharged, a programmable logic controller in the frequency converter is utilized to control a third intermediate relay in a switching-off control loop of the circuit breaker of the high-voltage outlet cabinet to be disconnected.
Preferably, the auxiliary contact string of the third intermediate relay is connected into the switching control circuit of the pre-charging vacuum contactor.
Preferably, the method further comprises the following steps:
The state of the pre-charging vacuum contactor and the state of the high-voltage outlet cabinet circuit breaker are detected in real time by using a programmable logic controller in the frequency converter, and when the pre-charging vacuum contactor and the high-voltage outlet cabinet circuit breaker are opened, the high-voltage inlet cabinet circuit breaker only has the condition of allowing closing, and the auxiliary contact of the fourth intermediate relay is controlled to be closed by using the programmable logic controller in the frequency converter, so that the high-voltage inlet cabinet is allowed to be electrified.
Preferably, the auxiliary contact string of the first intermediate relay is connected into a closing control circuit of the vacuum circuit breaker in the high-voltage outlet cabinet.
Preferably, a time relay is connected in a closing control loop of the vacuum circuit breaker in the high-voltage outlet cabinet.
Preferably, the time relay starts timing after the vacuum contactor is started to be attracted during the precharge, and the auxiliary contact of the time relay is closed after the set precharge time is reached, so that the high-voltage outlet cabinet circuit breaker is controlled to be closed.
The invention has the following beneficial effects:
The invention avoids the expansion of faults and even damage to the frying machine caused by faults found in the pre-charging process of the frequency converter, and simultaneously prevents the pre-charging resistor from being burnt out when the circuit breaker of the outlet cabinet is not switched on to the pre-charging resistor for a long time in the pre-charging state, thereby improving the quality and reliability of the frequency converter.
Drawings
FIG. 1 is a flow chart of a method for controlling high voltage precharge of a cascaded frequency converter of a power cell;
FIG. 2 is a logic diagram of a high voltage precharge control method for a power cell cascaded inverter;
FIG. 3 is a schematic diagram of a high voltage precharge control architecture for a power cell cascaded inverter;
Fig. 4 is a schematic diagram of a first intermediate relay for controlling the switching-on permission of a high-voltage outlet cabinet circuit breaker;
Fig. 5 is a schematic diagram of a high voltage outlet cabinet controlled vacuum contactor.
Detailed Description
The following description of the embodiments of the present invention is provided to facilitate understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and all the inventions which make use of the inventive concept are protected by the spirit and scope of the present invention as defined and defined in the appended claims to those skilled in the art.
As shown in fig. 1 and 2, an embodiment of the present invention provides a high voltage precharge control method for a power unit cascaded frequency converter, which includes steps S1 to S3 as follows:
S1, after a power supply in a frequency converter is started, determining whether to allow the frequency converter to be precharged or not by using a programmable logic controller in the frequency converter according to a system state and a state of each power unit;
s2, when the frequency converter is allowed to be precharged, a programmable logic controller in the frequency converter is used for controlling a first intermediate relay in a switching-on control loop of a vacuum circuit breaker in the high-voltage outlet cabinet to be closed, and switching-on of the circuit breaker of the high-voltage outlet cabinet is completed;
And S3, controlling the pre-charging vacuum contactor connected into the outlet cabinet to be disconnected by utilizing the normally closed auxiliary contact of the high-voltage outlet cabinet circuit breaker, and completing high-voltage pre-charging.
In an alternative embodiment of the present invention, the high voltage precharge control structure for the power unit cascade inverter of the present embodiment is shown in fig. 3, and includes a high voltage incoming line cabinet, a precharge vacuum contactor, a precharge resistor, a phase-shifting transformer and an inverter power cabinet which are sequentially connected, and high voltage outgoing line cabinet circuit breakers are connected in parallel at both ends of the precharge vacuum contactor and the precharge resistor; the variable frequency power cabinet comprises a plurality of power units and a frequency converter control cabinet, wherein a Programmable Logic Controller (PLC) is arranged in the frequency converter control cabinet, and the programmable logic controller is used for respectively collecting states of a high-voltage incoming line cabinet circuit breaker, a pre-charging vacuum contactor, a high-voltage outgoing line cabinet circuit breaker and the power units.
In an alternative embodiment of the present invention, the present embodiment uses a programmable logic controller within the frequency converter to determine whether to allow pre-charging of the frequency converter based on the system status and the status of each power cell, comprising the steps of:
comparing the acquired signals of the current sensor and the voltage sensor with corresponding set thresholds by utilizing a programmable logic controller in the frequency converter according to the digital input signal state; if the set threshold value is exceeded, the frequency converter fails; otherwise, the frequency converter has no fault;
detecting whether a heartbeat signal sent by a main board controller is received or not by using a programmable logic controller in the frequency converter; if yes, the frequency converter has no fault; otherwise, the frequency converter fails;
detecting whether a feedback signal sent by a power unit is received or not by using a main board controller in the frequency converter; if yes, the frequency converter has no fault; otherwise, the frequency converter fails;
When the frequency converter has no fault, comparing the voltage value of the direct current bus with a set voltage target value by utilizing a programmable logic controller in the frequency converter; if the voltage value of the direct current bus reaches the set voltage target value, allowing the high-voltage outlet cabinet circuit breaker to be switched on; otherwise, the high-voltage outlet cabinet circuit breaker is not allowed to be switched on.
Specifically, the transformer and the frequency converter are precharged simultaneously through the high-voltage side precharge resistor, the PLC in the frequency converter can determine whether to allow the high-voltage outlet cabinet circuit breaker to be switched on according to the voltage value of the precharged direct-current bus and the state of each power unit after the precharge is started, the high-voltage outlet cabinet circuit breaker is allowed to be switched on after the frequency converter has no faults and the voltage value of the precharged bus reaches a target value, the normally closed auxiliary contact string of the outlet cabinet circuit breaker is connected into the control coil of the precharge vacuum contactor, the precharge vacuum contactor is disconnected after the switch-on of the outlet cabinet is successful, the continuity of the whole precharge and electrifying processes is good, and formal main power is not needed to be supplied after the switch-off after the precharge is completed.
The judging method for the faults of the frequency converter comprises the following steps: the PLC and the main board controller can detect whether the variable frequency system has faults in real time on line after being electrified, the PLC can compare signal data acquired by the DI state, current, voltage sensor and the like of an input signal with a threshold value set in a program to further judge whether the faults exist, and communication between the main board controller and the PLC can detect whether a 'heartbeat' exists in real time to judge whether the communication is normal or not; and the main board controller and the power unit are communicated in real time through optical fibers, whether the optical fiber communication is normal or not is judged through whether feedback exists, and the faults detected by the PLC and the faults detected by the main board controller are reported through the PLC.
When the switch-on condition of the circuit breaker of the outlet cabinet is not met, the first intermediate relay KA11 controlled by the PLC can not be output, and then the circuit breaker of the high-voltage outlet cabinet can not be switched on.
As shown in fig. 4, in this embodiment, by adding a first intermediate relay KA11 for controlling the switching-on of the high-voltage outlet cabinet circuit breaker in the frequency converter, a normally open auxiliary contact string of the first intermediate relay KA11 is connected to a switching-on control loop of the vacuum circuit breaker in the high-voltage outlet cabinet, after the setting time of the time relay KT is up, an auxiliary contact of the time relay KT is closed, a PLC in the frequency converter is utilized to control the first intermediate relay KA11, whether the switching-on permission condition is met by controlling the high-voltage outlet cabinet circuit breaker through the auxiliary contact of the first intermediate relay KA11, the normally open auxiliary contact of the first intermediate relay KA11 is closed when the switching-on permission condition is met, and the switching-on coil of the vacuum circuit breaker is electrified to be switched on.
In an alternative embodiment of the present invention, the present embodiment further comprises the steps of:
When the frequency converter fails, a programmable logic controller in the frequency converter is utilized to control the second intermediate relay in the switching-off control loop of the high-voltage outlet cabinet circuit breaker to be attracted.
The auxiliary contact string of the second intermediate relay is connected into the switching-off control loop of the high-voltage outlet cabinet circuit breaker and the pre-charging vacuum contactor.
Specifically, when the switch-on condition of the circuit breaker of the outlet cabinet is not met, the PLC can send an instruction for enabling the pre-charging vacuum contactor KM1 to be disconnected, and the second intermediate relay KA7 is controlled to disconnect the pre-charging vacuum contactor KM1, so that the pre-charging resistor is prevented from being burnt out when the circuit breaker of the outlet cabinet is not switched on and the pre-charging resistor is in a pre-charging state for a long time.
In an alternative embodiment of the present invention, the present embodiment further comprises the steps of:
when the frequency converter is not allowed to be precharged, a programmable logic controller in the frequency converter is utilized to control a third intermediate relay in a switching-off control loop of the circuit breaker of the high-voltage outlet cabinet to be disconnected.
The auxiliary contact string of the third intermediate relay is connected into a brake separating control loop of the pre-charging vacuum contactor.
Specifically, in this embodiment, when a failure is detected after the PLC is powered on, the third intermediate relay KA12 outputs an instruction that the precharge is not allowed, and the precharge cannot be performed normally.
As shown in fig. 5, in this embodiment, two intermediate relays KA7 and KA12 are added to the frequency converter, auxiliary contact strings of KA7 and KA12 are connected to a switching control loop of a pre-charging contactor and a vacuum circuit breaker in the high-voltage outlet cabinet, the intermediate relays KA7 and KA12 are controlled by a PLC in the frequency converter, and switching of the circuit breaker of the high-voltage outlet cabinet and whether pre-charging is allowed or not are controlled by auxiliary contacts of the intermediate relays KA7 and KA 12.
The normally closed auxiliary contact of the high-voltage outlet cabinet circuit breaker is connected into the control coil of the pre-charging vacuum contactor in series, and after the outlet cabinet circuit breaker is successfully switched on, the normally closed auxiliary contact of the high-voltage outlet cabinet circuit breaker becomes a normally open contact, so that the control coil power supply of the pre-charging vacuum contactor is disconnected, and the pre-charging vacuum contactor is disconnected to complete the pre-charging function.
In an alternative embodiment of the present invention, the present embodiment further comprises the steps of:
The state of the pre-charging vacuum contactor, the state of the high-voltage outlet cabinet circuit breaker and the state of the upper-level high-voltage inlet cabinet circuit breaker are detected in real time by utilizing a programmable logic controller in the frequency converter, when the pre-charging vacuum contactor and the high-voltage outlet cabinet circuit breaker are opened, the high-voltage inlet cabinet circuit breaker only has the condition of allowing closing, and the auxiliary contact of the fourth intermediate relay KA1 is connected into a closing coil control loop of the high-voltage inlet cabinet circuit breaker in series, and the auxiliary contact of the fourth intermediate relay KA1 is controlled to be closed by utilizing the programmable logic controller in the frequency converter, so that the high-voltage inlet cabinet is allowed to be electrified.
Specifically, the PLC in the embodiment can detect the states of the vacuum contactor, the outgoing line cabinet circuit breaker and the upper-level incoming line cabinet circuit breaker in real time, and the incoming line cabinet circuit breaker cannot be electrified under the condition that the outgoing line cabinet circuit breaker or the vacuum contactor is not disconnected, and meanwhile, the circuit breaker has a voltage-loss tripping function, so that the safety of the whole frequency conversion system is ensured.
In an alternative embodiment of the invention, the embodiment switches in a time relay in a switching-on control loop of a vacuum circuit breaker in a high-voltage outlet cabinet.
The time relay starts timing after the vacuum contactor is started to be attracted during pre-charging, and the auxiliary contact of the time relay is closed after the pre-charging time is set, so that the high-voltage outlet cabinet circuit breaker is controlled to be closed.
According to the embodiment, before pre-charging, the frequency converter is powered on through a UPS (uninterrupted Power supply) to provide a control power supply for the PLC and the mainboard controller, after the power-on, the frequency converter can establish communication with the mainboard controller to automatically detect whether faults exist, the mainboard controller can judge whether faults exist according to a control program, the faults can be reported under the condition that the communication with the PLC is normal, the communication faults can be reported when the communication is abnormal, the PLC can display a sudden stop state when a sudden stop button is shot, pre-charging can be started when the faults and the sudden stop are not caused, the PLC in the frequency converter can start to pre-charge the frequency converter according to whether the busbar voltage value after pre-charging detected by the voltage detection module reaches 85% of rated busbar voltage or not and whether each power unit has faults and whether other faults are reported by the PLC or not, the high-voltage outgoing cabinet circuit breaker is allowed to be switched on or not is determined according to the control program, the auxiliary contact strings of the high-voltage outgoing cabinet circuit breaker are connected into a control coil of the pre-charging cabinet after the frequency converter has no faults and the busbar voltage value after the pre-charging reaches a target value, and the pre-charging function is successfully completed, and the pre-charging process is completed; and the time of precharge can be controlled by a time relay KT in the high-voltage outlet cabinet, as shown in the schematic diagram of the vacuum contactor controlled by the high-voltage outlet cabinet, after a closing button of the high-voltage outlet cabinet is pressed down, a contactor KM coil is controlled to be electrified, auxiliary contacts of KM connected in parallel at two ends of the closing button are closed, self-locking is formed, and the fact that the following time relay KT coil is electrified all the time and normally clocks is ensured. When the switch-on condition of the circuit breaker of the outlet cabinet is not met, the PLC can send a command for enabling the vacuum contactor to be disconnected, and the vacuum contactor is disconnected through the intermediate relay, so that the phenomenon that the precharge resistor is burnt out when the circuit breaker of the outlet cabinet is not switched on and the precharge resistor is in a precharge state for a long time is prevented.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The principles and embodiments of the present invention have been described in detail with reference to specific examples, which are provided to facilitate understanding of the method and core ideas of the present invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.
Those of ordinary skill in the art will recognize that the embodiments described herein are for the purpose of aiding the reader in understanding the principles of the present invention and should be understood that the scope of the invention is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific modifications and combinations from the teachings of the present disclosure without departing from the spirit thereof, and such modifications and combinations remain within the scope of the present disclosure.
Claims (10)
1. The high-voltage precharge control method for the power unit cascade frequency converter is characterized by comprising the following steps of:
After the power supply in the frequency converter is started, determining whether to allow the frequency converter to be precharged or not according to the system state and the state of each power unit by utilizing a programmable logic controller in the frequency converter;
when the frequency converter is allowed to be precharged, a programmable logic controller in the frequency converter is used for controlling a first intermediate relay in a switching-on control loop of a vacuum circuit breaker in the high-voltage outlet cabinet to be closed, so that switching-on of the circuit breaker of the high-voltage outlet cabinet is completed;
and (3) controlling the disconnection of a pre-charging vacuum contactor connected into the outlet cabinet by using a normally closed auxiliary contact of the high-voltage outlet cabinet circuit breaker, so as to complete high-voltage pre-charging.
2. The method of claim 1, wherein the step of determining whether to allow the pre-charging of the inverter based on the system state and the state of each power cell by using a programmable logic controller in the inverter comprises the steps of:
comparing the acquired signals of the current sensor and the voltage sensor with corresponding set thresholds by utilizing a programmable logic controller in the frequency converter according to the digital input signal state; if the set threshold value is exceeded, the frequency converter fails; otherwise, the frequency converter has no fault;
detecting whether a heartbeat signal sent by a main board controller is received or not by using a programmable logic controller in the frequency converter; if yes, the frequency converter has no fault; otherwise, the frequency converter fails;
detecting whether a feedback signal sent by a power unit is received or not by using a main board controller in the frequency converter; if yes, the frequency converter has no fault; otherwise, the frequency converter fails;
When the frequency converter has no fault, comparing the voltage value of the direct current bus with a set voltage target value by utilizing a programmable logic controller in the frequency converter; if the voltage value of the direct current bus reaches the set voltage target value, allowing the high-voltage outlet cabinet circuit breaker to be switched on; otherwise, the high-voltage outlet cabinet circuit breaker is not allowed to be switched on.
3. The method for controlling high voltage precharge of a power cell cascaded inverter of claim 2, further comprising the steps of:
When the frequency converter fails, a programmable logic controller in the frequency converter is utilized to control the second intermediate relay in the switching-off control loop of the high-voltage outlet cabinet circuit breaker to be attracted.
4. A method of controlling high voltage precharge of a cascaded inverter for a power cell as claimed in claim 3 wherein the auxiliary contact string of the second intermediate relay is connected to the switching control loop of the high voltage outlet tank circuit breaker and the precharge vacuum contactor.
5. The method for controlling high voltage precharge of a power cell cascaded inverter of claim 1, further comprising the steps of:
when the frequency converter is not allowed to be precharged, a programmable logic controller in the frequency converter is utilized to control a third intermediate relay in a switching-off control loop of the circuit breaker of the high-voltage outlet cabinet to be disconnected.
6. The method of claim 5, wherein the auxiliary contact string of the third intermediate relay is connected to the switching control loop of the pre-charging vacuum contactor.
7. The method for controlling high voltage precharge of a power cell cascaded inverter of claim 1, further comprising the steps of:
The state of the pre-charging vacuum contactor and the state of the high-voltage outlet cabinet circuit breaker are detected in real time by using a programmable logic controller in the frequency converter, and when the pre-charging vacuum contactor and the high-voltage outlet cabinet circuit breaker are opened, the high-voltage inlet cabinet circuit breaker only has the condition of allowing closing, and the auxiliary contact of the fourth intermediate relay is controlled to be closed by using the programmable logic controller in the frequency converter, so that the high-voltage inlet cabinet is allowed to be electrified.
8. The method for high voltage precharge control of a power cell cascaded inverter of claim 1, wherein the auxiliary contact string of the first intermediate relay is connected into a closing control loop of a vacuum circuit breaker in a high voltage outlet cabinet.
9. The method for controlling high voltage precharge of a cascaded frequency converter of a power cell according to claim 8, wherein a time relay is connected in a closing control loop of a vacuum circuit breaker in a high voltage outlet cabinet.
10. The method for controlling high voltage pre-charge for a power unit cascade inverter according to claim 9, wherein the time relay starts timing at the same time after the pre-charge starts the vacuum contactor to be closed, and the auxiliary contact of the time relay is closed after the pre-charge time is set, so as to control the high voltage outlet cabinet circuit breaker to be closed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410618465.7A CN118523602A (en) | 2024-05-17 | 2024-05-17 | High-voltage precharge control method for power unit cascade frequency converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410618465.7A CN118523602A (en) | 2024-05-17 | 2024-05-17 | High-voltage precharge control method for power unit cascade frequency converter |
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| CN118523602A true CN118523602A (en) | 2024-08-20 |
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| CN202410618465.7A Pending CN118523602A (en) | 2024-05-17 | 2024-05-17 | High-voltage precharge control method for power unit cascade frequency converter |
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- 2024-05-17 CN CN202410618465.7A patent/CN118523602A/en active Pending
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