High-voltage transfer cabinet and high-voltage transfer method between a power supply device and an inverter

Abstract

The present invention discloses a high-voltage transfer cabinet and a high-voltage transfer method between a power supply device and an inverter, belonging to the field of high-power power electronics technology. The high-voltage transfer cabinet of the present invention is provided with a channel connecting the power supply device and the inverter; the channel includes a pre-charge circuit, a main circuit breaker circuit connected in parallel with the pre-charge circuit, a discharge circuit, a voltage sensor, a current sensor, and an alarm device. The high-voltage transfer method of the present invention uses the high-voltage transfer cabinet for transfer, including closing the pre-charge contactor for pre-charging; when the voltages on the input side and the output side of the high-voltage transfer cabinet are less than a first set value, closing the main circuit breaker of the channel for charging. The present invention realizes the switching of the charge and discharge circuits of the inverter and the power supply path management under multiple application scenarios, and can release the excess voltage of the charging device at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-power power electronics, and particularly relates to a high-voltage transfer cabinet and a high-voltage transfer method between a power supply device and an inverter. Background Art

[0002] Due to the rapid economic development, high-voltage inverters are widely used in fields such as aviation, military, rail transit, and photovoltaic power generation. In this situation, it is urgent to improve the production efficiency of inverters and shorten the stock preparation cycle. The transfer cabinets used in the prior art have complex wiring when the voltage level is relatively high; and a large number of insulating partitions are used, making the cabinet structure very complex, and it is very inconvenient to use and maintain during the test process. Therefore, it is particularly crucial to simplify the wiring method inside the cabinet while ensuring the insulation withstand voltage level, and to facilitate the use and maintenance during the inverter test in multiple application scenarios. Summary of the Invention

[0003] The object of the present invention is to provide a high-voltage transfer cabinet and a high-voltage transfer method between a power supply device and an inverter, which can realize the switching of the charge and discharge circuits of the inverter and the power supply path management in multiple application scenarios, and can release the excess voltage of the charging device at the same time.

[0004] Specifically, on the one hand, the present invention provides a high-voltage transfer cabinet between a power supply device and an inverter, which is provided with a channel connecting the power supply device and the inverter; the channel includes:

[0005] A pre-charge circuit for preventing the charging current from exceeding the current upper limit that the inverter can withstand when charging the inverter;

[0006] A main circuit breaker circuit in parallel with the pre-charge circuit, on which a main circuit breaker is provided, and when the main circuit breaker is closed, the power supply device charges the inverter;

[0007] A discharge circuit, on which a discharge output circuit breaker and a discharge resistor are provided, and when the discharge output circuit breaker is closed, the channel discharges;

[0008] A voltage sensor for detecting the voltage on the input side and / or output side of the high-voltage transfer cabinet;

[0009] A current sensor for detecting the charging current when charging the inverter;

[0010] An alarm device for generating and displaying an alarm when an abnormality occurs during the operation process.

[0011] Furthermore, the pre-charge circuit includes a series-connected pre-charge contactor and a pre-charge resistor.

[0012] Furthermore, the voltage sensor includes a first voltage sensor for detecting the positive and negative voltages on the input side; a second voltage sensor for detecting the positive voltage and the middle voltage on the input side; and a third voltage sensor for detecting the positive and negative voltages on the output side.

[0013] Furthermore, an isolation contactor is provided between the middle terminal on the input side and the middle terminal on the output side of the channel; there are two channels, and a parallel connection contactor is connected in parallel between the two channels; the parallel output of the two channels is realized by closing the isolation contactor and the parallel connection contactor.

[0014] Furthermore, the high-voltage transfer cabinet between the power supply device and the inverter further includes an emergency stop button. When the emergency stop button is pressed, the main circuit breaker and the pre-charge contactor in the closed state are immediately tripped.

[0015] Furthermore, the high-voltage transfer cabinet between the power supply device and the inverter further includes a controller for collecting voltage and current data and the working states of each pre-charge contactor, main circuit breaker switch, isolation contactor, and parallel connection contactor, and controlling and protecting the charging process of the inverter in combination with the parameter limits set on the controller.

[0016] On the other hand, the present invention provides a high-voltage transfer method between a power supply device and an inverter, which uses the high-voltage transfer cabinet between the power supply device and the inverter for transfer, including:

[0017] Closing the pre-charge contactor to perform pre-charging;

[0018] When the voltages on the input side and the output side of the high-voltage transfer cabinet are less than the first set value, closing the main circuit breaker of the channel to perform charging.

[0019] Furthermore, the high-voltage transfer method between the power supply device and the inverter includes the following steps:

[0020] The controller sends a disconnection command to the main circuit breaker, discharge output circuit breaker, isolation contactor, pre-charge contactor, and parallel connection contactor according to the set power supply mode to make them in the disconnected state;

[0021] After the controller receives the pre-charge start signal generated when the pre-charge button is pressed, it sends a closing command for the pre-charge contactor to perform pre-charging;

[0022] During the pre-charging process, the controller performs protection judgment, that is, if after a specified time of pre-charging, if the output side voltage value is not within the set range, the controller generates an alarm, disconnects the pre-charge contactor, and the operation process ends;

[0023] The controller makes a judgment based on the voltage values between the positive and negative poles on the input side and the output side of the high-voltage transfer cabinet. If the voltages between the positive and negative poles on the input side and the output side of both channels are less than the second set value, the controller sends a closing command for the main circuit breaker to close the main circuit breaker for charging. If the input side and output side voltages are still not less than the second set value when the preset pre-charging time ends, the controller generates an alarm and sends a tripping command for the pre-charging contactor to trip the pre-charging contactor.

[0024] The controller receives the closing result signal of the main circuit breaker and judges whether the main circuit breaker has been effectively closed. If the controller receives this signal within the specified time, it is judged that the main circuit breaker has been effectively closed. If the controller does not receive this signal within the specified time, an alarm is generated, the pre-charging contactor and the main circuit breaker are tripped, and the operation process ends.

[0025] After the main circuit breaker has been closed for 1S, the controller sends a tripping command for the pre-charging contactor to the pre-charging contactor to end the pre-charging process.

[0026] Furthermore, after the controller receives the pre-charging start signal generated when the pre-charging button is pressed, it also judges the voltage detected in real time on the input side of the high-voltage transfer cabinet, including:

[0027] According to the voltage detected in real time by the voltage sensor on the input side of the high-voltage transfer cabinet, it is judged whether the voltage difference between the positive and negative poles of the two channels is less than or equal to the third set value. If it is greater than the third set value, pre-charging cannot be performed, an alarm is generated, and the operation process ends. If it is less than or equal to the third set value, the controller sends a closing command for the pre-charging contactor for pre-charging.

[0028] Furthermore, the high-voltage transfer method between the power supply device and the inverter includes the following steps:

[0029] The controller sends a disconnection command to the main circuit breaker, the discharge output circuit breaker, the isolation contactor, the pre-charging contactor, and the parallel connection contactor according to the set power supply mode to make them in the disconnected state.

[0030] The controller sends a closing command to the parallel connection contactor to close it.

[0031] After the controller receives the pre-charging start signal generated when the pre-charging button is pressed, it calculates the voltage difference between the positive pole and the midpoint on the input side of the high-voltage transfer cabinet and the voltage difference between the midpoint and the negative pole, and judges whether the difference is less than or equal to the fourth set value. If it is greater than the fourth set value, pre-charging cannot be performed, an alarm is generated, and the operation process ends. If it is less than or equal to the fourth set value, the next step is carried out.

[0032] The controller sends a closing command to the isolation contactor to close it.

[0033] The controller sends a closing command to the pre-charge contactor for pre-charging;

[0034] During the pre-charging process, the controller performs protection judgment, that is, if after a specified time of pre-charging, if the output-side voltage value is not within the set range, the controller generates an alarm, disconnects the pre-charge contactor, and the operation process ends;

[0035] The controller makes a judgment based on the voltage values between the positive and negative poles of the input side and the output side of the high-voltage transfer cabinet. When the voltage between the positive and negative poles of the input side and the output side is less than the fifth set value, the controller sends a closing command to the main circuit breaker to close the main circuit breaker for charging; if the voltage between the positive and negative poles of the input side and the output side is still not less than the fifth set value when the preset pre-charging time ends, the controller generates an alarm and sends a tripping command to the pre-charge contactor to trip the pre-charge contactor;

[0036] The controller receives the closing result signal of the main circuit breaker and judges whether the main circuit breaker has been effectively closed. If the controller receives this signal within the specified time, it is judged that the main circuit breaker has been effectively closed; if the controller does not receive this signal within the specified time, an alarm is generated, and the pre-charge contactor and the main circuit breaker are tripped, and the operation process ends;

[0037] After the main circuit breaker is closed for 1S, the controller sends a tripping command to the pre-charge contactor to trip it and end the pre-charging process.

[0038] The beneficial effects of the high-voltage transfer cabinet and the high-voltage transfer method between the power supply device and the inverter of the present invention are as follows:

[0039] The present invention is applicable to the testing of single-voltage power supply type inverters, dual-voltage power supply type inverters and similar devices, and can realize the switching of the charge and discharge loop and the power supply path management between the charging device and the inverter; the dual-channel parallel output function can be realized through contactor control. When the controller is used to conveniently and reliably realize the switching of the charge and discharge loop and the power supply path management between the charging device and the inverter in multiple application scenarios, manual switching is not required during the testing process of the inverter device, and the operation safety factor is improved.

[0040] A pre-charge loop is added, and the inverter device is pre-charged through the pre-charge loop, avoiding the generation of a large charging current when the voltage difference between the input end and the output end of the high-voltage transfer cabinet is large, exceeding the current upper limit that the inverter can withstand, thereby better protecting the inverter device.

[0041] After the testing of the inverter device is completed, the excess voltage of the charging device can be released through the discharge loop to ensure the safety of personnel and equipment in subsequent operations. Description of the Drawings

[0042] Figure 1 It is the electrical principle schematic diagram of Embodiment 1 of the present invention.

[0043] Figure 2 It is the operation flow chart of Embodiment 1 of the present invention (Scenario 1).

[0044] Figure 3 It is the operation flow chart of Embodiment 1 of the present invention (Scenario 2).

[0045] Figure 4 It is the operation flow chart of Embodiment 1 of the present invention (Scenario 3).

[0046] Figure 5 It is the schematic diagram of the PLC control system of Embodiment 2 of the present invention.

[0047] Figure 6 It is the PLC control flow chart of Embodiment 2 of the present invention (Scenario 1).

[0048] Figure 7 It is the PLC control flow chart of Embodiment 2 of the present invention (Scenario 2).

[0049] Figure 8 It is the PLC control flow chart of Embodiment 2 of the present invention (Scenario 3). Detailed implementation manners

[0050] The present invention will be further described in detail below in conjunction with the embodiments and with reference to the accompanying drawings.

[0051] Embodiment 1:

[0052] An embodiment of the present invention is a high-voltage transfer cabinet between a power supply device and an inverter. As Figure 1As shown, the high-voltage transfer cabinet between the power supply device and the inverter provides two channels (Channel 1 and Channel 2) for connecting the power supply device. The P1, O1, and N1 terminals on the input side of Channel 1 are respectively connected to the corresponding P, O, and N terminals of the power supply device through cables, and the P1’, O1’, and N1’ terminals on the output side are connected to the P, O, and N terminals on the input side of the inverter through cables; the P2, O2, and N2 terminals on the input side of Channel 2 are respectively connected to the corresponding P, O, and N terminals of the power supply device through cables, and the P2’, O2’, and N2’ terminals on the output side are connected to the P, O, and N terminals on the input side of the inverter through cables. Channel 1 includes a pre-charge circuit 1 and a main breaker circuit 1 in parallel therewith. Among them, the pre-charge circuit 1 consists of pre-charge contactors KM1, KM2, pre-charge resistors R1, R2; a main breaker QF1 of Channel 1 is provided on the main breaker circuit 1, and an isolation contactor QS1 is provided between the O1 terminal and the O1’ terminal, and QS1 is disconnected when powering a single-voltage supply inverter. Channel 2 includes a pre-charge circuit 2 and a main breaker circuit 2 in parallel therewith. Among them, the pre-charge circuit 2 consists of pre-charge contactors KM3, KM4, pre-charge resistors R3, R4, a main breaker QF2 of Channel 2 is provided on the main breaker circuit 2, and an isolation contactor QS2 is provided between the O2 terminal and the O2’ terminal. QS1 and QS2 are disconnected when powering a single-voltage supply inverter.

[0053] Parallel connection contactors QS3, QS4, and QS5 are connected in parallel between Channel 1 and Channel 2. By closing the isolation contactors QS1, QS2 and the parallel connection contactors QS3, QS4, and QS5, the parallel output of Channel 1 and Channel 2 is realized.

[0054] On the main breaker circuit of Channel 1, a discharge circuit 1 is provided between the power supply device and the pre-charge circuit, including a discharge output breaker QF3 and a discharge resistor R5. The P and N terminals of the discharge circuit 1 are connected to the P and N terminals of the main breaker circuit 1 through cables. At any time when needed, the discharge of Channel 1 can be realized by closing the discharge output breaker QF3. On the main breaker circuit of Channel 2, a discharge circuit 2 is provided between the power supply device and the pre-charge circuit, including a discharge output breaker QF4 and a discharge resistor R6. The P and N terminals of the discharge circuit 2 are connected to the P and N terminals of the main breaker circuit 2 through cables. At any time when needed, the discharge of Channel 2 can be realized by closing the discharge output breaker QF4.

[0055] At the input end of the 1st channel of the high-voltage transfer cabinet, there are voltage sensors V11 and V12 for detecting the input-side voltage of the 1st channel of the high-voltage transfer cabinet, and a current sensor A1 for detecting the input current of the 1st channel; at the output end, there is a voltage sensor V13 for detecting the output-side voltage of the 1st channel of the high-voltage transfer cabinet. At the input end of the 2nd channel of the high-voltage transfer cabinet, there are voltage sensors V21 and V22 for detecting the input-side voltage of the 2nd channel of the high-voltage transfer cabinet, and a current sensor A2 for detecting the input current of the 2nd channel; at the output end, there is a voltage sensor V23 for detecting the output-side voltage of the 2nd channel of the high-voltage transfer cabinet. Through these voltage sensors and current sensors, the voltage and current data on the input side and output side of the high-voltage transfer cabinet are collected in real time, and the voltage and current values are displayed through the digital display on the high-voltage transfer cabinet.

[0056] To avoid a large charging current exceeding the current upper limit that the inverter can withstand when the voltage difference between the input end and the output end of the high-voltage transfer cabinet is large, a pre-charge circuit is added to pre-charge the inverter equipment through the pre-charge circuit. A pre-charge resistor is set on the pre-charge circuit so that the charging current will not be too large during the pre-charge process. When the voltage difference between the input side and the output side of the high-voltage transfer cabinet is less than a specific value (such as 5V) or the pre-charge time is greater than a specific value (such as 40S), the main circuit breaker is closed. At the same time, the pre-charge contactor is separated, and the voltage is output from the output end of the high-voltage transfer cabinet to the inverter to realize the charging function of the power supply equipment to the inverter.

[0057] The 1st channel and the 2nd channel of the high-voltage transfer cabinet in this embodiment can supply power to different inverters respectively (hereinafter referred to as Scenario 1); they can also be output from the 1st channel and the 2nd channel to different voltage segments of the same inverter and be connected in parallel on the inverter (hereinafter referred to as Scenario 2); they can also be connected in parallel on the high-voltage transfer cabinet and then output to the same inverter (hereinafter referred to as Scenario 3).

[0058] For Scenario 1, taking the 1st channel as an example below, it is explained how the power supply equipment supplies power to the inverter through a single channel of the high-voltage transfer cabinet. The operation process of charging the inverter using a single channel of the above high-voltage transfer cabinet is as Figure 2 shown.

[0059] The first step: Confirm that the main circuit breaker QF1, the discharge output circuit breaker QF3, the isolation contactor QS1, the pre-charge contactors KM1, KM2, the parallel connection contactors QS3, QS4, and QS5 are in the off state.

[0060] The second step: Close the pre-charge contactors KM1 and KM2 to perform pre-charging. At this time, the other contactors are in the off state.

[0061] During the pre-charging process, protection judgment is carried out. That is, if after the pre-charging passes the specified time and the output side voltage value is not within the set range, the alarm indicator light of the high-voltage transfer cabinet will turn on. At this time, the pre-charging contactor KM1 is disconnected and the operation process ends. For example, when the pre-charging is completed for 1S, it is detected whether the output side voltage value (i.e., the voltage value detected by the voltage sensor V13) is 200V±20V; when the pre-charging is completed for 2S, it is detected whether the output side voltage value is 800V±20V; when the pre-charging is completed for 3S, it is detected whether the output side voltage value is 1200V±20V; when the pre-charging is completed for 4S, it is detected whether the output side voltage value is 2100V±20V; the specific detection time and the corresponding voltage threshold for generating an alarm can be set according to actual needs. This protection judgment is only made once during the pre-charging process and will not be made again after the main circuit breaker is closed.

[0062] Step 3: Judge according to the input side and output side voltage values (i.e., the detected voltage difference between the voltage sensors V13 and V11) displayed on the digital display meter on the high-voltage transfer cabinet. When the input side and output side voltages are less than 5V, close the No. 1 main circuit breaker QF1 to start charging.

[0063] Step 4: Judge whether the main circuit breaker has been effectively closed according to the closing indicator light. If the closing indicator light is normal, proceed to the next step; otherwise, the alarm indicator light will turn on after 15S and the operation process ends.

[0064] Step 5: Open the pre-charging contactor to end the pre-charging process.

[0065] For Scenario 2, the operation process of charging the inverter using the above high-voltage transfer cabinet is as Figure 3 shown.

[0066] Step 1: Confirm that the main circuit breakers QF1 and QF2, the discharge output circuit breakers QF3 and QF4, the isolation contactors QS1 and QS2, the pre-charging contactors KM1, KM2, KM3, and KM4, and the parallel connection contactors QS3, QS4, and QS5 are in the off state.

[0067] Step 2: Judge according to the detected voltage values of the input side voltage sensors V11 and V21 displayed on the digital display meter on the high-voltage transfer cabinet whether the difference between them (i.e., the difference between the voltage between P1 and N1 and the voltage between P2 and N2) is less than or equal to 50V. If it is greater than 50V, pre-charging cannot be carried out, the alarm indicator light will turn on, and the operation process ends; if it is less than or equal to 50V, proceed to the next step.

[0068] Step 3: Close the pre-charging contactors KM1, KM2, KM3, and KM4 to start pre-charging. At this time, the other contactors are in the off state.

[0069] During the pre-charging process, protection judgment is carried out. That is, if after a specified time of pre-charging, the output-side voltage value is not within the set range, the alarm indicator light of the high-voltage transfer cabinet will turn on. At this time, the pre-charging contactors KM1, KM2, KM3, and KM4 will be disconnected, and the operation process ends. For example, when the pre-charging is completed for 1 s, it is detected whether the output-side voltage value (i.e., the voltage values detected by the voltage sensors V13 and V23) is 200 V ± 20 V; when the pre-charging is completed for 2 s, it is detected whether the output-side voltage value is 800 V ± 20 V; when the pre-charging is completed for 3 s, it is detected whether the output-side voltage value is 1200 V ± 20 V; when the pre-charging is completed for 4 s, it is detected whether the output-side voltage value is 2100 V ± 20 V; the specific detection time and the corresponding voltage threshold for generating an alarm can be set according to actual needs. This protection judgment is only made once during the pre-charging process and is not made again after the main circuit breaker is closed.

[0070] Step 4: Make a judgment based on the input-side and output-side voltage values (i.e., the detected voltage differences between the voltage sensors V13 and V11, and the detected voltage differences between the voltage sensors V23 and V21) displayed on the digital display meter on the high-voltage transfer cabinet. When the input-side and output-side voltages of both channels are less than 5 V, close the main circuit breakers QF1 and QF2 to start charging.

[0071] Step 5: Judge whether the main circuit breaker has been effectively closed according to the closing indicator light. If the closing indicator light is normal, proceed to the next step; otherwise, the alarm indicator light will turn on after 15 s, and the operation process ends.

[0072] Step 6: Open the pre-charging contactors to end the pre-charging process.

[0073] For Scenario 3, the power supply device supplies power to the inverter through the parallel connection of Channel 1 and Channel 2 of the high-voltage transfer cabinet. The operation process of charging the inverter using the above high-voltage transfer cabinet is as Figure 4 shown

[0074] Step 1: Confirm that the main circuit breakers QF1 and QF2, the discharge output circuit breakers QF3 and QF4, the isolation contactors QS1 and QS2, the pre-charging contactors KM1, KM2, KM3, KM4, and the parallel connection contactors QS3, QS4, and QS5 are in the off state.

[0075] Step 2: Close the parallel connection contactors QS3, QS4, and QS5.

[0076] Step 3: Calculate the difference between the detected voltage values of the input-side voltage sensors V11 and V12 (|V12 - V11|) shown on the digital display meter of the high-voltage transfer cabinet, and determine whether the difference between |V12 - V11| and V12 (i.e., the voltage difference between P1 and O1 and the voltage difference between O1 and N1) is less than or equal to 30V. If it is greater than 30V, pre-charging cannot be performed, the alarm indicator light will turn on, and the operation process ends; if it is less than or equal to 30V, proceed to the next step.

[0077] Step 4: Close the isolation contactors QS1 and QS2.

[0078] Step 5: Close the pre-charging contactors KM1, KM2, KM3, and KM4 to perform pre-charging.

[0079] During the pre-charging process, perform protection judgment. That is, if after a specified time of pre-charging, the output-side voltage value is not within the set range, the alarm indicator light of the high-voltage transfer cabinet will turn on. At this time, disconnect the pre-charging contactors KM1, KM2, KM3, and KM4, and the operation process ends. For example, when pre-charging is completed for 1S, check whether the output-side voltage value (i.e., the voltage value detected by the voltage sensor V13 or V23) is 200V ± 20V; when pre-charging is completed for 2S, check whether the output-side voltage value is 800V ± 20V; when pre-charging is completed for 3S, check whether the output-side voltage value is 1200V ± 20V; when pre-charging is completed for 4S, check whether the output-side voltage value is 2100V ± 20V; the specific detection time and the corresponding voltage threshold for generating an alarm can be set according to actual needs. This protection judgment is only made once during the pre-charging process and will not be made again after the main circuit breaker is closed.

[0080] Step 6: Judge according to the input-side and output-side voltage values (i.e., the detected voltage difference between the voltage sensors V13 and V11 or the detected voltage difference between the voltage sensors V23 and V21) shown on the digital display meter of the high-voltage transfer cabinet. When the input-side and output-side voltages are less than 5V, close the main circuit breakers QF1 and QF2 to perform charging.

[0081] Step 7: Judge whether the main circuit breakers QF1 and QF2 have been effectively closed according to the closing indicator light. If the closing indicator light is normal, proceed to the next step; otherwise, the alarm indicator light will turn on after 15S, and the operation process ends.

[0082] Step 8: Open the pre-charging contactors KM1, KM2, KM3, and KM4 to end the pre-charging process.

[0083] During the test process of the inverter equipment, large voltages and large currents pass through. When an abnormal situation occurs, the main circuit breaker and the pre-charging contactor in the closed state can be immediately opened by pressing the emergency stop button to cut off the charging equipment and protect the safety of the inverter equipment.

[0084] After the inverter device test is completed, through the discharge circuit, the excess voltage of the charging device can be released to ensure the safety of personnel and equipment in subsequent operations.

[0085] Both the front and rear doors of the high-voltage transfer cabinet can be opened, and the door panels on both the left and right sides of the cabinet are detachable for convenient internal maintenance. Heat dissipation vents are provided on the door panels on both the left and right sides of the cabinet, which can effectively dissipate heat from the cabinet. When a large current short circuit occurs, an effective pressure relief channel can be formed to ensure safety.

[0086] To ensure that the cabinet does not malfunction due to cabinet shaking when high voltage and high current pass through, the cabinet can be fixed to the ground.

[0087] Embodiment 2:

[0088] Another embodiment of the present invention, different from Embodiment 1, includes a monitoring system on the basis of Embodiment 1, providing an intelligent automated protection function. According to the power demand of the system inverter device for the power supply, automatic / manual, parallel / branch switching of the power supply is realized through the human-machine interface, and its application scenario is the same as that of Embodiment 1.

[0089] As Figure 5 shown, the monitoring system of this embodiment includes a PLC, a voltage sensor, and a current sensor. The PLC collects voltage, current data and the working states of each pre-charging contactor, main circuit breaker switch, isolation contactor, and parallel connection contactor in real time through the voltage sensor and the current sensor, transmits the relevant information to the upper computer, and receives the instructions of the upper computer. Combining with the parameter limits set on the PLC, the operating conditions can be comprehensively judged to realize the automatic control and protection of the high-voltage transfer cabinet by the monitoring system. It can be understood that a remote control function can also be provided to remotely monitor the high-voltage transfer cabinet through the network. A pre-start button, an emergency stop button, and a discharge button are also provided on the high-voltage transfer cabinet. The pre-start button is used to start the pre-charging process, the emergency stop button is used to trip each circuit breaker and contactor in an emergency, and the discharge button is used to close the discharge output circuit breaker QF4 at any time when needed to realize the discharge of the channel. It can be understood that the PLC can be implemented by other controllers such as a single-chip microcomputer, DCS, and FCS to realize the corresponding functions.

[0090] For Scenario 1, taking Channel 1 as an example below, it is described how the power supply device supplies power to the inverter through a single channel of the high-voltage transfer cabinet. The operation process of charging the inverter using the above high-voltage transfer cabinet with an automated protection function is as Figure 6 shown.

[0091] Step 1: After setting the power supply mode of Scenario 1 through the host computer, the PLC sends out disconnection commands to the main circuit breaker QF1, discharge output circuit breaker QF3, isolation contactor QS1, pre-charge contactors KM1, KM2, parallel connection contactors QS3, QS4, and QS5 to make them in the disconnected state.

[0092] Step 2: Manually press the pre-charge button. After the PLC receives the corresponding pre-charge start signal, it closes the pre-charge contactors KM1 and KM2 for pre-charging. At this time, except for the emergency stop button and the discharge button, other buttons are invalid.

[0093] The closing result signal of the pre-charge contactor is fed back to the PLC. If the PLC does not receive this signal within 1S, the PLC generates an alarm and the operation process ends.

[0094] During the pre-charge process, the PLC conducts protection judgment, that is, if after a specified time of pre-charging, the output side voltage value is not within the set range, the PLC generates an alarm, disconnects the pre-charge contactors KM1 and KM2, and the operation process ends. For example, when the pre-charge is completed in 1S, it is detected whether the output side voltage value (i.e., the voltage value detected by the voltage sensor V13) is 200V±20V; when the pre-charge is completed in 2S, it is detected whether the output side voltage value is 800V±20V; when the pre-charge is completed in 3S, it is detected whether the output side voltage value is 1200V±20V; when the pre-charge is completed in 4S, it is detected whether the output side voltage value is 2100V±20V; the specific detection time and the corresponding voltage threshold for generating an alarm can be set according to actual needs. This protection judgment is only made once during the pre-charge process and is not made again after the main circuit breaker is closed.

[0095] Step 3: The PLC makes a judgment based on the voltage values of the input side and output side of the high-voltage transfer cabinet (i.e., the voltage difference detected by the voltage sensors V13 and V11 in real time). When the input side and output side voltages are less than 5V, the PLC sends a closing command for the No. 1 main circuit breaker to make the No. 1 main circuit breaker QF1 close for charging. If the input side and output side voltages are still not less than 5V when the preset pre-charge time ends, the PLC generates an alarm and sends a disconnection command for the pre-charge contactor to make the pre-charge contactors KM1 and KM2 open, and the operation process ends. Only when the input side and output side voltages are less than 5V, manually pressing the main circuit breaker closing button is effective, otherwise the main circuit breaker button is invalid.

[0096] Step 4: The PLC receives the closing result signal of the main circuit breaker and judges whether the main circuit breaker has been effectively closed. If this signal is received within the specified time (such as 15S), it is judged that the main circuit breaker has been effectively closed; if this signal is not received within 15S, an alarm is generated and the operation process ends.

[0097] Step 5: After the main circuit breaker is effectively closed for 1 s, the PLC sends a tripping command for the pre-charging contactor to the pre-charging contactor, ending the pre-charging process.

[0098] Step 6: The PLC receives the tripping result signal of the pre-charging contactor. If this signal is obtained within the specified time (such as 15 s), it is determined that the pre-charging contactor has been effectively tripped and the pre-charging process ends; if this signal is not obtained within 15 s, an alarm is generated.

[0099] For Scenario 2, the operation process of charging the inverter using the above high-voltage transfer cabinet is as Figure 7 shown.

[0100] Step 1: After setting the power supply mode of Scenario 2 through the host computer, the PLC sends a disconnection command to the main circuit breakers QF1 and QF2, the discharge output circuit breakers QF3 and QF4, the isolation contactors QS1 and QS2, the pre-charging contactors KM1, KM2, KM3, and KM4, and the paralleling contactors QS3, QS4, and QS5 to make them in the disconnected state.

[0101] Step 2: Manually press the pre-charging button. After the PLC receives the corresponding pre-charging start signal, it continuously detects the voltages of the voltage sensors V11 and V21 on the input side of the high-voltage transfer cabinet in real time and determines whether the difference between the two (i.e., the difference between the voltages between P1 and N1 and between P2 and N2) is less than or equal to 50 V. If it is greater than 50 V, pre-charging cannot be performed and an alarm is generated, ending the operation process; if it is less than or equal to 50 V, proceed to the next step. After manually pressing the pre-charging button, all buttons are invalid except for the emergency stop button and the discharge button.

[0102] Step 3: The PLC sends a closing command to the pre-charging contactors KM1, KM2, KM3, and KM4 for pre-charging. At this time, the other contactors are in the open state.

[0103] The closing result signal of the pre-charging contactor is fed back to the PLC. If the PLC does not receive this signal within 1 s, the PLC generates an alarm and the operation process ends.

[0104] During the pre-charging process, the PLC performs protection judgment. That is, if after a specified time of pre-charging, the output-side voltage value is not within the set range, the PLC generates an alarm, disconnects the pre-charging contactors KM1, KM2, KM3, and KM4, and the operation process ends. For example, when the pre-charging is completed for 1 s, it is detected whether the output-side voltage value (i.e., the voltage values detected by the voltage sensors V13 and V23) is 200V ± 20V; when the pre-charging is completed for 2 s, it is detected whether the output-side voltage value is 800V ± 20V; when the pre-charging is completed for 3 s, it is detected whether the output-side voltage value is 1200V ± 20V; when the pre-charging is completed for 4 s, it is detected whether the output-side voltage value is 2100V ± 20V; the specific detection time and the corresponding voltage threshold for generating an alarm can be set according to actual needs. This protection judgment is only made once during the pre-charging process and is not made again after the main circuit breaker is closed.

[0105] Fourth step: The PLC makes a judgment based on the input-side and output-side voltage values of the high-voltage transfer cabinet (i.e., the detected voltage difference between the voltage sensors V13 and V11, and the detected voltage difference between the voltage sensors V23 and V21). If the input-side and output-side voltages of both channels are less than 5V, the PLC sends a main circuit breaker closing command to close the main circuit breakers QF1 and QF2 for charging; if the input-side and output-side voltages are still not less than 5V when the preset pre-charging time ends, the PLC generates an alarm and sends a pre-charging contactor opening command to open the pre-charging contactors KM1, KM2, KM3, and KM4. Only when the input-side and output-side voltages are less than 5V, pressing the main circuit breaker closing button manually is effective, otherwise the main circuit breaker button is ineffective.

[0106] Fifth step: The PLC receives the main circuit breaker closing result signal and judges whether the main circuit breaker has been effectively closed. If the PLC receives this signal within the specified time (such as 15 s), it is judged that the main circuit breaker has been effectively closed; if the PLC does not receive this signal within 15 s, an alarm is generated, the pre-charging contactors KM1, KM2, KM3, and KM4 are opened, and the main circuit breakers QF1 and QF2 are opened, and the operation process ends.

[0107] Sixth step: 1 s after the main circuit breaker is closed, the PLC sends a pre-charging contactor opening command to the pre-charging contactor to end the pre-charging process.

[0108] Seventh step: The PLC receives the pre-charging contactor opening result signal. If the signal is received within the specified time (such as 15 s), it is judged that the pre-charging contactor has been effectively opened and the pre-charging process ends; if the signal is not received within 15 s, an alarm is generated.

[0109] For Scenario 3, the power supply device supplies power to the inverter through the parallel connection of Channel 1 and Channel 2 of the high-voltage transfer cabinet. The operation process of charging the inverter using the above high-voltage transfer cabinet is asFigure 8 as shown

[0110] Step 1: After setting the power supply mode of Scenario 3 through the host computer, the PLC sends disconnection commands to the main circuit breakers QF1 and QF2, the discharge output circuit breakers QF3 and QF4, the isolation contactors QS1 and QS2, the pre-charge contactors KM1, KM2, KM3, and KM4, and the paralleling contactors QS3, QS4, and QS5 to make them in the disconnected state.

[0111] Step 2: The PLC sends closing commands to the paralleling contactors QS3, QS4, and QS5 to make them closed.

[0112] Step 3: Manually press the pre-charge button. After the PLC receives the corresponding pre-charge start signal, it detects the voltage in real time according to the voltage sensors V11 and V12 on the input side of the high-voltage transfer cabinet, calculates the difference between the two (|V12 - V11|), and determines whether the difference between |V12 - V11| and V12 (i.e., the voltage difference between P1 and O1 and the voltage difference between O1 and N1) is less than or equal to 30V. If it is greater than 30V, pre-charging cannot be performed, an alarm is generated, and the operation process ends; if it is less than or equal to 30V, the next step is carried out. After manually pressing the pre-charge button, except for the emergency stop button and the discharge button, other buttons are invalid.

[0113] Step 4: The PLC sends closing commands to the isolation contactors QS1 and QS2 to make them closed.

[0114] The closing result signal of the isolation contactor is fed back to the PLC. If the PLC does not receive this signal within 1S, the PLC generates an alarm and the operation process ends.

[0115] Step 5: The PLC sends closing commands to the pre-charge contactors KM1, KM2, KM3, and KM4 for pre-charging.

[0116] The closing result signal of the pre-charge contactor is fed back to the PLC. If the PLC does not receive this signal within 1S, the PLC generates an alarm and the operation process ends.

[0117] During the pre-charging process, the PLC performs protection judgment. That is, if after a specified time of pre-charging, the output-side voltage value is not within the set range, the PLC generates an alarm and disconnects the pre-charging contactors KM1, KM2, KM3, and KM4, and the operation process ends. For example, when the pre-charging is completed in 1 s, it is detected whether the output-side voltage value (i.e., the voltage value detected by the voltage sensor V13 or V23) is 200 V ± 20 V; when the pre-charging is completed in 2 s, it is detected whether the output-side voltage value is 800 V ± 20 V; when the pre-charging is completed in 3 s, it is detected whether the output-side voltage value is 1200 V ± 20 V; when the pre-charging is completed in 4 s, it is detected whether the output-side voltage value is 2100 V ± 20 V; the specific detection time and the corresponding voltage threshold for generating an alarm can be set according to actual needs. This protection judgment is only made once during the pre-charging process and is not made again after the main circuit breaker is closed.

[0118] Step 6: The PLC makes a judgment based on the input-side and output-side voltage values of the high-voltage transfer cabinet (i.e., the difference in the detected voltages of the voltage sensors V13 and V11 or the difference in the detected voltages of the voltage sensors V23 and V21). When the input-side and output-side voltages are less than 5 V, the PLC sends a main circuit breaker closing instruction to make the main circuit breakers QF1 and QF2 close for charging; if the input-side and output-side voltages are still not less than 5 V when the preset pre-charging time ends, the PLC generates an alarm and sends a pre-charging contactor opening instruction to make the pre-charging contactors KM1, KM2, KM3, and KM4 open. Only when the input-side and output-side voltages are less than 5 V, pressing the main circuit breaker closing button manually is effective, otherwise the main circuit breaker closing button is ineffective.

[0119] Step 7: The PLC receives the main circuit breaker closing result signal and judges whether the main circuit breakers QF1 and QF2 have been effectively closed. If the PLC receives this signal within the specified time (such as 15 s), it is judged that the main circuit breaker has been effectively closed; if the PLC does not receive this signal within 15 s, an alarm is generated, the pre-charging contactors KM1, KM2, KM3, and KM4 are opened, and the main circuit breakers QF1 and QF2 are opened, and the operation process ends.

[0120] Step 8: 1 s after the main circuit breaker is closed, the PLC sends a tripping instruction to the pre-charging contactor to make it trip and ends the pre-charging process.

[0121] Step 9: The PLC receives the pre-charging contactor tripping result signal. If it receives this signal within the specified time (such as 15 s), it is judged that the pre-charging contactor has been effectively tripped and the pre-charging process ends; if it does not receive this signal within 15 s, an alarm is generated.

[0122] During the testing process of the inverter device, high voltage and large current pass through. When an abnormal situation occurs, the host computer can send an emergency stop control instruction to the PLC to immediately trip the main circuit breaker and pre-charge contactor in the closed state, cut off the charging device, and protect the safety of the inverter device.

[0123] After the testing of the inverter device is completed, the redundant voltage of the charging device can be released through the discharge circuit to ensure the safety of personnel and equipment in subsequent operations.

[0124] The high-voltage transfer cabinet in this embodiment not only undertakes the on-off in power distribution, but also has functions such as measurement, control, protection, and communication. It is also a bridge connecting primary electrical equipment and secondary intelligent control and protection equipment. Preset parameter values can be set according to the characteristics of the large-capacity DC power system itself and the complex working conditions of the application scenarios, focusing on important performance indicators such as the main frame structure strength of the switch cabinet, electrical insulation, temperature rise of the main and bypass busbars, protection level, electromagnetic compatibility, short-circuit breaking capacity, and the intelligence and standardization of the digital monitoring and protection system.

[0125] The present invention is applicable to the testing of single-voltage power supply type inverters, dual-voltage power supply type inverters, and similar devices, and can realize the switching of the charge-discharge circuit and the power supply path management between the charging device and the inverter; the dual-channel parallel output function can be achieved through contactor control. When using the PLC to conveniently and reliably realize the switching of the charge-discharge circuit and the power supply path management between the charging device and the inverter in multiple application scenarios, manual switching is not required during the testing process of the inverter device, improving the operation safety factor.

[0126] Although the present invention has been disclosed above with preferred embodiments, the embodiments are not used to limit the present invention. Any equivalent changes or modifications made without departing from the spirit and scope of the present invention also belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the content defined by the claims of this application.

Claims

1. A high-voltage transfer method between a power supply device and an inverter, which uses a high-voltage transfer cabinet between the power supply device and the inverter for transfer. The high-voltage transfer cabinet between the power supply device and the inverter is provided with a channel connecting the power supply device and the inverter; the channel includes: A pre-charge circuit, which is used to prevent the charging current from exceeding the current upper limit that the inverter can withstand when charging the inverter; A main circuit breaker circuit connected in parallel with the pre-charge circuit, on which a main circuit breaker is provided. When the main circuit breaker is closed, the power supply device charges the inverter; A discharge circuit, on which a discharge output circuit breaker and a discharge resistor are provided. When the discharge output circuit breaker is closed, the channel discharges; A voltage sensor, which is used to detect the voltage on the input side and / or output side of the high-voltage transfer cabinet; A current sensor, which is used to detect the charging current when charging the inverter; An alarm device, which is used to generate and display an alarm when an abnormality occurs during the operation process; It further includes a controller, which is used to collect voltage and current data and the working states of each pre-charge contactor, main circuit breaker switch, isolation contactor, and parallel connection contactor, and combine the parameter limits set on the controller to control and protect the charging process of the inverter; It is characterized in that the high-voltage transfer method between the power supply device and the inverter includes the following steps: The controller sends a disconnection command to the main circuit breaker, discharge output circuit breaker, isolation contactor, pre-charge contactor, and parallel connection contactor according to the set power supply mode, so that they are in a disconnected state; After the controller receives the pre-charge start signal generated when the pre-charge button is pressed, it sends a closing command to the pre-charge contactor to perform pre-charging; During the pre-charging process, the controller performs a protection judgment, that is, if after a specified time of pre-charging, if the output side voltage value is not within the set range, the controller generates an alarm, disconnects the pre-charge contactor, and the operation process ends; The controller judges according to the voltage values between the positive and negative poles of the input side and output side of the channel connecting the power supply device and the inverter in the high-voltage transfer cabinet. If the difference between the voltages between the positive and negative poles of the input side and output side of the two channels connecting the power supply device and the inverter is less than the second set value, the controller sends a closing command to the main circuit breaker to make the main circuit breaker close and charge; if the difference between the input side and output side voltages of the channel connecting the power supply device and the inverter is still not less than the second set value when the preset pre-charging time ends, the controller generates an alarm and sends a disconnection command to the pre-charge contactor to make the pre-charge contactor disconnect; The controller receives the main circuit breaker closing result signal and judges whether the main circuit breaker has been effectively closed. If the controller gets this signal within the specified time, it is judged that the main circuit breaker has been effectively closed; if the controller does not get this signal within the specified time, an alarm is generated, and the pre-charge contactor and the main circuit breaker are disconnected, and the operation process ends; After the main circuit breaker is closed for 1 S, the controller sends a disconnection command to the pre-charge contactor to the pre-charge contactor to end the pre-charging process.

2. The high-voltage transfer method between a power supply device and an inverter according to claim 1, characterized in that After the controller receives the pre-charge start signal generated when the pre-charge button is pressed, it also judges the real-time detected voltage on the input side of the high-voltage transfer cabinet, including: According to the voltage detected by the voltage sensor on the input side of the high-voltage transfer cabinet, determine whether the voltage difference between the positive and negative voltages of the two channels is less than or equal to the third set value. If it is greater than the third set value, pre-charging cannot be performed, an alarm is generated, and the operation process ends; if it is less than or equal to the third set value, the controller sends a closing command to the pre-charging contactor to perform pre-charging.

3. The high-voltage transfer method between the power supply device and the inverter according to claim 1, characterized in that, It includes the following steps: The controller sends a disconnection command to the main circuit breaker, discharge output circuit breaker, isolation contactor, pre-charging contactor, and parallel connection contactor according to the set power supply mode to make them in the disconnected state; The controller sends a closing command to the parallel connection contactor to make it close; After the controller receives the pre-charging start signal generated when the pre-charging button is pressed, calculate the voltage difference between the positive electrode and the midpoint on the input side of the high-voltage transfer cabinet and the voltage difference between the midpoint and the negative electrode, and determine whether the difference is less than or equal to the fourth set value. If it is greater than the fourth set value, pre-charging cannot be performed, an alarm is generated, and the operation process ends; if it is less than or equal to the fourth set value, proceed to the next step; The controller sends a closing command to the isolation contactor to make it close; The controller sends a closing command to the pre-charging contactor to perform pre-charging; During the pre-charging process, the controller performs protection judgment, that is, if after a specified time of pre-charging, if the output side voltage value is not within the set range, the controller generates an alarm, disconnects the pre-charging contactor, and the operation process ends; The controller makes a judgment based on the voltage values between the positive and negative electrodes on the input side and output side of the high-voltage transfer cabinet. When the voltage between the positive and negative electrodes on the input side and output side is less than the fifth set value, the controller sends a closing command to the main circuit breaker to make the main circuit breaker close for charging; if the voltage between the positive and negative electrodes on the input side and output side is still not less than the fifth set value when the preset pre-charging time ends, the controller generates an alarm and sends a tripping command to the pre-charging contactor to make the pre-charging contactor trip; The controller receives the closing result signal of the main circuit breaker and judges whether the main circuit breaker has been effectively closed. If the controller receives this signal within the specified time, it is judged that the main circuit breaker has been effectively closed; if the controller does not receive this signal within the specified time, an alarm is generated, and the pre-charging contactor and the main circuit breaker are tripped, and the operation process ends; 1 s after the main circuit breaker is closed, the controller sends a tripping command to the pre-charging contactor to make it trip, ending the pre-charging process.

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