Compressor high-voltage electric control system and method

Abstract

The invention discloses a compressor high-voltage electric control system and method. The system comprises a controller and N sections of compressors arranged in sequence. N is an integer greater than or equal to 2; the compressor is used for inflating an air storage device in the compressed air storage system; in the inflation operation process, air of the first N-1 sections of compressors in the N sections of compressors is cooled to the set temperature through the air-water heat exchanger and the water cooler so as to maintain the rated working condition; and the last section of compressor in the N sections of compressors realizes variable-working-condition operation through guide vane adjustment or variable-frequency adjustment. According to the technical scheme provided by the invention, the operation requirements of quick start-stop and quick response of the compressor are met.

Description

Technical Field

[0001] The present invention relates to the technical field of compressed air energy storage, and in particular to a compressor high-voltage electronic control system and method. Background Art

[0002] Compressed air energy storage technology, as a large-scale, long-term energy storage technology with large capacity, long cycle, safety, environmental protection and long life, has become one of the mainstream energy storage technologies in recent years.

[0003] The basic process is that when the power grid is at a low load, the excess electricity is converted into the internal energy and part of the heat energy of compressed air through an air compressor, and the compressed air is stored in a high-pressure sealed container or underground cave; when the power grid is at a peak, the compressed air drives the air turbine to convert the internal energy into electrical energy. The air turbine generator set is a key device in the compressed air energy storage system. When the energy storage system is discharged, the air turbine generator set will expand the stored high-pressure air and convert it into electrical energy.

[0004] The compressor is the core equipment of the compressed air storage system. The compressor high-pressure control should be configured according to the equipment operation needs. Summary of the invention

[0005] The embodiments of the present invention provide a high-voltage electronic control system and method for a compressor to achieve the operation requirements of rapid start and stop and rapid response of the compressor.

[0006] In a first aspect, an embodiment of the present invention provides a compressor high-voltage electric control system, comprising: a controller and N-stage compressors arranged in sequence; N is an integer greater than or equal to 2;

[0007] The compressor is used to inflate the air storage device in the compressed air storage system; during the charging operation, the air of the first N-1 compressors in the N compressors is cooled to the set temperature through the air-water heat exchanger and the water cooler to maintain the rated operating conditions; the last compressor in the N compressors realizes variable operating conditions through guide vane adjustment or frequency conversion adjustment.

[0008] The compressor is used to inflate the air storage device in the compressed air storage system; during the charging operation, the air of the first N-1 compressors in the N compressors is cooled to the set temperature through the air-water heat exchanger and the water cooler to maintain the rated operating conditions; the last compressor in the N compressors realizes variable operating conditions through guide vane adjustment or frequency conversion adjustment.

[0009] In a second aspect, an embodiment of the present invention further provides a compressor high-voltage electronic control method, which is applicable to a compressor high-voltage electronic control system provided by any embodiment of the present invention, wherein the compressor high-voltage electronic control system comprises a controller and N-stage compressors arranged in sequence; N is an integer greater than or equal to 2;

[0010] The compressor high-voltage electronic control method comprises:

[0011] During the charging process of the air storage device in the compressed air storage system, the controller controls the air of the first N-1 compressors in the N compressors to be cooled to a set temperature through the air-water heat exchanger and the water cooler to maintain the rated working condition;

[0012] The controller controls the last compressor of the N-stage compressor to achieve variable operating condition operation through guide vane adjustment or frequency conversion adjustment.

[0013] In the present invention, the compressor high-voltage electronic control system controller and N-stage compressors are arranged in sequence; N is an integer greater than or equal to 2; the compressor is used to inflate the air storage device in the compressed air storage system; during the inflation operation, the air of the first N-1 compressors in the N-stage compressors is cooled to the set temperature through the air-water heat exchanger and the water cooler to maintain the rated operating conditions; the last compressor in the N-stage compressors realizes variable operating conditions through guide vane adjustment or frequency conversion adjustment. In this embodiment, in the process of inflating the air storage device in the compressed air storage system, the first N-1 compressors are adiabatic compression and are always in rated operating conditions. The last compressor is used for variable operating conditions adjustment, and the compressor outlet pressure increases with the increase of the air storage pressure to adapt to the change of outlet pressure during the inflation process. The operating requirements of rapid start and stop and rapid response of the compressor are realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic structural diagram of a compressor high-voltage electronic control system provided by an embodiment of the present invention;

[0015] Figure 2 A schematic structural diagram of a compressed air storage system provided by an embodiment of the present invention;

[0016] Figure 3 A schematic structural diagram of a compressed air storage system provided by an embodiment of the present invention;

[0017] Figure 4 A schematic flow chart of a compressor high-voltage electronic control method provided by an embodiment of the present invention;

[0018] Figure 5 A schematic flow chart of another compressor high-voltage electronic control method provided by an embodiment of the present invention;

[0019] Figure 6 A high voltage control wiring diagram provided for an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0021] As the proportion of renewable energy increases, long-term energy storage becomes a trend of future development. Compressed air energy storage, as a long-term energy storage, has the advantages of large energy storage capacity, high safety, long life, economy and environmental protection. The compressor is the core equipment of the compressed air energy storage system, and the compressor high-pressure control should be configured according to the operation needs of the equipment. In order to achieve the operation requirements of rapid start and stop and rapid response of the compressor, this embodiment develops a new type of high-voltage electronic control design for the compressor.

[0022] like Figure 1 As shown, Figure 1 A schematic diagram of the structure of a compressor high-voltage electronic control system provided by an embodiment of the present invention, Figure 2 A schematic diagram of the structure of a compressed air storage system provided in an embodiment of the present invention. An embodiment of the present invention provides a compressor high-voltage electronic control system, comprising: a controller 11 and N-stage compressors 12 arranged in sequence; N is an integer greater than or equal to 2;

[0023] The compressor 12 is used to inflate the air storage device 21 in the compressed air storage system; during the charging operation, the air of the first N-1 compressors in the N compressors is cooled to the set temperature through the air-water heat exchanger 14 and the water cooler 15 to maintain the rated operating conditions; the last compressor 12 in the N compressors 12 realizes variable operating conditions through guide vane adjustment or frequency conversion adjustment.

[0024] like Figure 2 As shown, the compressed air storage system includes a charging air circuit L1, a discharging air circuit L2, a charging water circuit L3 and a discharging water circuit L4. When the power consumption is low, the motor 13 drives the compressor 12 to suck in the air in the environment and compress it into high-temperature and high-pressure air, which is stored in the air storage device 21, and the electrical energy is converted into internal energy to complete the energy input process; at the same time, the cold water in the cold water storage tank 23 absorbs the heat in the high-temperature and high-pressure air through the air-water heat exchanger 14, and the temperature is increased to form hot water and transmitted to the hot water storage tank 22; during the peak power consumption period, the high-pressure air in the air storage device 21 drives the turbine 24 to work, drives the generator 26 to generate electricity, and the internal energy is converted into mechanical energy, and the mechanical energy is converted into electrical energy, thereby completing the energy output. At the same time, the hot water in the hot water storage tank 22 heats the air output from the air storage device 21 through the heater 25, and the hot water cools down and is transmitted to the cold water storage tank 23 through the water cooler 15.

[0025] refer to Figure 1In this embodiment, the first N-1 compressors in the N-stage compressors use adiabatic compressed air energy storage technology. The adiabatic compressed air energy storage technology uses an air-water heat exchanger 14 and a water cooler 15 to recover the heat generated during the compression process, and use this part of the heat to heat the air entering the inlet of the turbine 24, thereby realizing the exchange of heat during the energy storage and energy release process. And each process is carried out under approximately adiabatic conditions, so that the system efficiency is improved. The compressor 12 inflates the air storage device 21, which is divided into N-stage compressors 12 for compression. The first N-1 compressors 12 are adiabatic compressions. After being cooled to the set temperature by the air-water heat exchanger 14 and the water cooler 15, the next stage of compression is carried out, and the last stage of compression is used for variable operating condition adjustment. During the inflation operation, the compressor outlet pressure increases with the increase of the gas reservoir pressure. The first N-1 stages of compression are always in rated operating condition operation (stable import and export parameters), and the last stage is operated in variable operating condition through guide vane adjustment or frequency conversion adjustment to maintain the first N-1 stages (if N is 4, such as Figure 2 As shown, the compressor of the first three sections operates stably and adapts to the change of outlet pressure during the charging process. In this embodiment, N can take a value greater than or equal to 2, and optionally, N can be 4. This embodiment can realize rapid start and stop of the unit and reduce hardware cost and pipeline design cost.

[0026] In an embodiment of the present invention, a compressor high-voltage electronic control system controller and N compressors are arranged in sequence; N is an integer greater than or equal to 2; the compressor is used to inflate the air storage device in the compressed air storage system; during the inflation operation, the air of the first N-1 compressors in the N compressors is cooled to the set temperature through the air-water heat exchanger and the water cooler to maintain the rated operating conditions; the last compressor in the N compressors realizes variable operating conditions through guide vane adjustment or frequency conversion adjustment. In this embodiment, in the process of inflating the air storage device in the compressed air storage system, the first N-1 compressors are adiabatic compression and are always in rated operating conditions. The last compressor is used for variable operating conditions adjustment, and the compressor outlet pressure increases with the increase of the air storage pressure to adapt to the change of outlet pressure during the inflation process. The operating requirements of the compressor for rapid start and stop and rapid response are realized.

[0027] The above is the core idea of ​​the present invention. The technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. 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.

[0028] Optionally, N=4; the first three compressors among the N-stage compressors can adopt variable frequency soft start and industrial frequency operation mode; the fourth compressor among the N-stage compressors can adopt variable frequency speed regulation operation mode or industrial frequency operation mode. In the high-voltage electronic control design, in order to meet the compressor drive system's start-up, operation, shutdown, and fault protection in a reasonable process, control interlocking points and status feedback points that communicate with the frequency converter and the compressor control system (referred to as controller 11 in this embodiment) are reasonably set in the medium-voltage switch cabinet's opening and closing circuit and the signal alarm circuit. Figure 3 As shown, Figure 3 A schematic diagram of the structure of another compressor high-voltage electronic control system provided in an embodiment of the present invention. The compressor 12 may include multiple sections, and in this embodiment, there are four sections. The one-stage, two-stage, and three-stage compressors in the schematic diagram of the structure of the compressor high-voltage electronic control system adopt variable frequency soft start and industrial frequency operation, and the four-stage compressor motor adopts a variable frequency speed regulation operation mode, and can also be switched to industrial frequency operation. Therefore, the frequency converter 31 needs to meet the variable frequency speed regulation of the motor 13 of the four-stage compressor 12, while selecting the variable frequency soft start of the one-stage compressor motor according to the maximum power, and at the same time meet the use of the motors of the two-stage, three-stage, and four-stage compressors. The electronic control technology solution of this embodiment is applicable to four compressor units for compressed air energy storage devices, and can realize rapid start and stop of the units.

[0029] Continue to refer Figure 3 Optionally, the compressor high-voltage electric control system may also include at least two inverters 31; the controller 11 is connected to the inverter 31 via a connecting line (hard line) or a wireless signal (communication signal); the controller 11 is also used to control the switching between at least two inverters. Optionally, the inverter may include: a first inverter and a second inverter; the controller realizes the mutual standby function between the first inverter and the second inverter through a connecting switch. This project is equipped with a total of 4 compressor motors and one inverter. Among them, the motors of compressors 1# to 3# adopt the mode of variable frequency soft start and industrial frequency operation; the motor of compressor 4# adopts the mode of variable frequency speed regulation, and can also be switched to industrial frequency operation. And the mutual standby function between the two inverters can be realized through a connecting switch.

[0030] Optionally, the compressor high-voltage electric control system may further include: a conversion switch; a controller including a field operation column and a remote compressor controller; when the conversion switch is in a first switch state, the controller starts the local operation mode so that the field operation column starts and stops the compressor; when the conversion switch is in a second switch state, the controller starts the remote operation mode so that the remote compressor controller starts and stops the compressor. Optionally, in the remote operation mode, the field operation column is invalid for the compressor operation. The high-voltage electric control is divided into two working modes: local and remote: first, the local operation mode, the field operation column is provided with a first switch state / second switch state (remote / local) conversion switch, when the conversion switch is turned to the second switch state (local position), the motor start / stop control is in the local operation mode, which is suitable for starting / stopping the compressor on site; second, the remote operation mode, when the conversion switch on the field operation column is turned to the first switch state (remote position), the motor start / stop control is in the remote operation mode, and the compressor is controlled by the start / stop command sent by the remote compressor controller CCS, and the local start compressor operation is invalid at this time.

[0031] Continue to refer Figure 3 The high-voltage electric control system of the compressor includes two major parts: the compressor electric drive chain and the auxiliary low-voltage power supply and distribution system of the unit. Among them, the design part related to the electric drive chain is called high-voltage electric control design, which involves the compressor drive equipment-medium-voltage motor to the electrical equipment at the user's 10kV medium-voltage power supply, such as high-voltage busbars, high-voltage cabinets, transformers, and transformers are electrically connected in sequence. According to the process requirements of the compressor, the unit adopts motor variable frequency speed regulation. The motor inverter starts, and the starting current multiple during the starting process is lower than the rated current. The design part related to the auxiliary low-voltage power supply and distribution of the unit is called low-voltage electric control design, which involves the compressor oil station, lubrication system, medium-voltage motor, and power distribution of low-voltage auxiliary equipment with a voltage level of 380 / 220V (or 220 / 110V) on the compressor, as well as the start-stop control and protection of these equipment.

[0032] Based on the same concept, an embodiment of the present invention further provides a compressor high-voltage electronic control method, which is applicable to a compressor high-voltage electronic control system provided by any embodiment of the present invention. The compressor high-voltage electronic control system includes a controller and N-stage compressors arranged in sequence; N is an integer greater than or equal to 2, Figure 4 A flow chart of a compressor high-voltage electronic control method provided by an embodiment of the present invention is shown in FIG. Figure 4 As shown, the method of this embodiment includes the following steps:

[0033] Step S110, during the charging process of the air storage device in the compressed air storage system, the controller controls the air of the first N-1 compressors in the N compressors to be cooled to a set temperature through an air-water heat exchanger and a water cooler to maintain rated operating conditions.

[0034] Step S120: The controller controls the last compressor of the N-stage compressor to achieve variable operating condition operation through guide vane adjustment or frequency conversion adjustment.

[0035] In an embodiment of the present invention, a compressor high-voltage electronic control system controller and N compressors are arranged in sequence; N is an integer greater than or equal to 2; the compressor is used to inflate the air storage device in the compressed air storage system; during the inflation operation, the air of the first N-1 compressors in the N compressors is cooled to the set temperature through the air-water heat exchanger and the water cooler to maintain the rated operating conditions; the last compressor in the N compressors realizes variable operating conditions through guide vane adjustment or frequency conversion adjustment. In this embodiment, in the process of inflating the air storage device in the compressed air storage system, the first N-1 compressors are adiabatic compression and are always in rated operating conditions. The last compressor is used for variable operating conditions adjustment, and the compressor outlet pressure increases with the increase of the air storage pressure to adapt to the change of outlet pressure during the inflation process. The operating requirements of the compressor for rapid start and stop and rapid response are realized.

[0036] Based on the above embodiments, Figure 5 As shown, Figure 5 A flow chart of another compressor high-voltage electronic control method provided by an embodiment of the present invention is shown in FIG. Figure 5 As shown, the method of this embodiment includes the following steps:

[0037] Step S210, controlling the first N-1 compressors among the N compressors to adopt variable frequency soft start and industrial frequency operation.

[0038] Optionally, controlling the first N-1 compressors among the N compressors to adopt variable frequency soft start may include: the controller issues a command to close the inverter incoming cabinet switch to control the closing of the incoming switch; the inverter is powered on at high voltage; the inverter receives a start command and closes the isolation cabinet switch to start the inverter; the inverter drives the compressor motor to accelerate to the grid frequency; the inverter monitors the grid voltage and the output voltage of the inverter, and controls the error between the output voltage and the grid voltage amplitude within a first threshold range, and controls the error between the output voltage and the grid voltage phase within a second threshold range; the controller issues a command to close the motor industrial frequency cabinet to control the closing of the motor industrial frequency cabinet, so that the variable frequency and industrial frequency simultaneously drive the motor; the inverter detects that the motor industrial frequency cabinet is closed, and simultaneously opens the motor's isolation switch.

[0039] Figure 6This is a high-voltage control wiring diagram provided for an embodiment of the present invention. This project is equipped with a total of 4 compressors and two frequency converters. The motors of compressors 1# to 3# (M1, M2 and M3) adopt variable frequency soft start and industrial frequency operation; the 4# motor (M4) adopts variable frequency speed regulation operation, and can also be switched to industrial frequency operation. And the two frequency converters can be used as backup for each other through a connecting switch. Motors 1#, 2#, and 3# are in variable frequency soft start working mode. Each group of matching frequency converters first converts the motors 1# to 3# into variable frequency soft start and connects them to the grid without disturbance. Taking any one of the motors as an example, the relevant logic is described as follows:

[0040] Step 1: The motor is ready to start, the compressor process and electrical (including the first inverter are ready) meet the starting conditions, and wait for the start command; Step 2: The on-site operation column or CCS issues a command to close the switch of the first inverter incoming cabinet, the incoming switch is closed, the first inverter is powered on at high voltage, the frequency conversion self-test is ready, there is no fault, no alarm, and the ready state is fed back to the CCS; Step 3: The first inverter receives the start command, closes the isolation cabinet switch of the motor, and starts the frequency conversion. The first inverter detects the grid voltage and the inverter output voltage in real time, and drives the motor to accelerate to the grid frequency (50Hz); Step 4: After the motor accelerates to the grid frequency (50Hz), adjust the amplitude and phase of the output voltage of the first inverter so that the frequency, amplitude, and phase of the output voltage of the first inverter are consistent with those of the grid voltage, and the control system detects that the amplitude and phase errors of the two are within the threshold range. Specifically, the error of the amplitude of the output voltage and the grid voltage is controlled to be within the first threshold range, and the error of the phase of the output voltage and the grid voltage is controlled to be within the second threshold range. Afterwards, a command is issued to close the power frequency cabinet of the motor, and the power frequency cabinet is closed. At this time, the motor is driven by both variable frequency and power frequency at the same time.

[0041] Step S220, controlling the last compressor of the N-stage compressor to adopt the variable frequency speed regulation operation mode or the industrial frequency operation mode.

[0042] Controlling the last compressor of the N-stage compressor to adopt variable frequency speed regulation operation mode or industrial frequency operation mode may include: after the start-up of the first N-1 compressors is completed, controlling the last compressor of the N-stage compressor to adopt variable frequency drag or industrial frequency drag. After the start-up of the motors 1# to 3# of each group is completed, the motor 4# adopts the variable frequency drive speed regulation operation, and can also be operated by variable frequency / industrial frequency switching according to process requirements.

[0043] In addition, when the first inverter fails or is under maintenance, the second inverter is started. The second inverter is required to start the four motors in group A. The first three inverters are soft-started and connected to the grid without disturbance, and the fourth motor is operated with variable speed.

[0044] The starting logic is as follows:

[0045] Step 1: The motor is ready to start, the compressor process and electrical (including the second inverter is ready) meet the starting conditions and wait for the start command; Step 2: The on-site operation column or CCS issues a second inverter incoming cabinet switch closing command, the incoming switch is closed, the second inverter is powered on at high voltage, the inverter self-test is ready, there is no fault, no alarm, and the ready state is fed back to the CCS; Step 3: The second inverter receives the start command, closes the isolation cabinet switch of the motor, and starts the frequency conversion. The second inverter detects the grid voltage and the inverter output voltage in real time, and drives the motor to accelerate to the grid frequency (50Hz); Step 4: After the motor accelerates to the grid frequency (50Hz), adjust the amplitude and phase of the inverter output voltage so that the frequency, amplitude, and phase of the output voltage of the second inverter are consistent with those of the grid voltage. The control system detects that the amplitude and phase errors of the two are within the threshold range. Specifically, the error of the amplitude of the output voltage and the grid voltage is controlled to be within the first threshold range, and the error of the phase of the output voltage and the grid voltage is controlled to be within the second threshold range. Afterwards, a command is issued to close the power frequency cabinet of the motor, and the power frequency cabinet is closed. At this time, the motor is driven by both variable frequency and power frequency at the same time.

[0046] It can be seen from the above that the startup process of the second frequency converter is similar to that of the first frequency converter, and the first frequency converter and the second frequency converter are backup devices for each other. In this embodiment, this project is equipped with a total of 4 compressor motors and one frequency converter. Compressors 1#~3# adopt variable frequency soft start and industrial frequency operation; the 4# motor adopts variable frequency speed regulation operation, and can also be switched to industrial frequency operation. And the mutual backup function between the two frequency converters can be realized through the connecting switch. After the startup of motors 1#~3# of each group is completed, the 4# motor adopts the frequency converter to drag and adjust the speed. According to the process requirements, it can also switch between variable frequency / industrial frequency. This embodiment realizes the operating requirements of rapid start and stop and rapid response of the compressor, and improves the working performance of the compressed air storage system.

[0047] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A compressor high-voltage electronic control system, characterized in that: include: A controller and N-stage compressors arranged in sequence; N is an integer greater than or equal to 2; The compressor is used to inflate the air storage device in the compressed air storage system; during the charging operation, the air of the first N-1 compressors in the N compressors is cooled to the set temperature through the air-water heat exchanger and the water cooler to maintain the rated operating conditions; the last compressor in the N compressors realizes variable operating conditions through guide vane adjustment or frequency conversion adjustment.

2. The compressor high-voltage electronic control system according to claim 1, characterized in that: Also includes: Transfer switch; The controller includes a field operation column and a remote compressor controller; When the conversion switch is in the first switch state, the controller starts the local operation mode so that the local operation column can start and stop the compressor; When the conversion switch is in the second switch state, the controller starts the remote operation mode so that the remote compressor controller starts and stops the compressor.

3. The compressor high-voltage electronic control system according to claim 2, characterized in that: In the remote operation mode, the local operation column is ineffective for operating the compressor.

4. The compressor high-voltage electronic control system according to claim 1, characterized in that: N＝4； The first three compressors of the N-stage compressor adopt variable frequency soft start and industrial frequency operation mode; the fourth compressor of the N-stage compressor adopts variable frequency speed regulation operation mode or industrial frequency operation mode.

5. The compressor high-voltage electronic control system according to claim 1, characterized in that: Also includes: At least two frequency converters; the controller is connected to the frequency converter via a connecting wire or a wireless signal; The controller is also used to control the switching operation between the at least two frequency converters.

6. The compressor high-voltage electronic control system according to claim 5, characterized in that: The frequency converter comprises: a first frequency converter and a second frequency converter; The controller realizes the mutual backup function between the first frequency converter and the second frequency converter through a tie switch.

7. A compressor high voltage electronic control method, characterized in that: The compressor high-voltage electronic control system is applicable to any one of claims 1 to 6, wherein the compressor high-voltage electronic control system comprises a controller and N compressors arranged in sequence; N is an integer greater than or equal to 2; The compressor high-voltage electronic control method comprises: During the charging process of the air storage device in the compressed air storage system, the controller controls the air of the first N-1 compressors in the N compressors to be cooled to a set temperature through the air-water heat exchanger and the water cooler to maintain the rated working condition; The controller controls the last compressor of the N-stage compressor to achieve variable operating condition operation through guide vane adjustment or frequency conversion adjustment.

8. The compressor high voltage electronic control method according to claim 7, characterized in that: The compressor high-voltage electronic control method specifically comprises: Control the first N-1 compressors of the N compressors to adopt variable frequency soft start and industrial frequency operation; The last compressor of the N-stage compressor is controlled to adopt a variable frequency speed regulation operation mode or an industrial frequency operation mode.

9. The compressor high voltage electronic control method according to claim 8, characterized in that: Controlling the first N-1 compressors of the N compressors to adopt variable frequency soft start, including: The controller issues a switch closing command for the inverter incoming cabinet to control the incoming switch to close; the inverter is powered on at high voltage; The frequency converter receives a start instruction and closes the isolation cabinet switch to start the frequency converter; The frequency converter drives the motor of the compressor to accelerate to the grid frequency; The frequency converter monitors the grid voltage and the output voltage of the frequency converter, and controls the error between the output voltage and the grid voltage in amplitude to be within a first threshold range, and controls the error between the output voltage and the grid voltage in phase to be within a second threshold range; The controller issues a command to close the motor power frequency cabinet to control the motor power frequency cabinet to close, so that the variable frequency and power frequency drive the motor at the same time; The frequency converter detects that the power frequency cabinet of the motor is closed and opens the isolating switch of the motor at the same time.

10. The compressor high voltage electronic control method according to claim 8, characterized in that: Controlling the last compressor of the N-stage compressor to adopt variable frequency speed regulation operation mode or industrial frequency operation mode, including: After the start-up of the first N-1 compressors is completed, the last compressor of the N compressors is controlled to adopt variable frequency drive or industrial frequency drive.

Images