Comprehensive test bench and test method for large marine pod power system

Abstract

The invention discloses a comprehensive test bench and test method for a large-scale marine pod power system. The test bench includes a transformer module, a drive module, a loading module, a control and monitoring station and a circulating water system. The drive module includes a first drive unit and a second drive unit. The output end of a three-winding rectifier transformer is connected to the input end of the first drive unit. The output end of the first drive unit is connected to a large-scale marine pod motor being tested in the loading module through a switch wiring cabinet. The drive units include a frequency converter, a voltage transformer, a current transformer and a brake resistor cabinet respectively. The control and monitoring station includes an industrial computer, a PLC controller, a car clock and an AVL controller. The circulating water system includes a water supply unit, a cooling unit and a circulating water pool. The test method includes a startup step A and a shutdown step B. The invention can realize three functions of energy feedback, energy storage and energy reuse, with significant energy-saving effect, and improves the test efficiency of large-scale marine pod motors.

Description

Technical Field

[0001] The invention relates to a test device for a ship propulsion system, in particular to a comprehensive test bench and test method for a large-scale ship pod motor (N≥10MW), belonging to the technical field of ship electric propulsion systems. Background Art

[0002] Water transportation includes inland waterway transportation, coastal and ocean shipping, and undertakes more than 80% of the world's material transportation. With the development of ship power technology, automation, intelligence and low carbonization have become the current development hotspots. The integrated electric propulsion system has the advantages of wide speed regulation range, easy forward and reverse rotation, small size, flexible layout, and no harmful gas emissions. It has become the representative of today's advanced ship power system. However, most of the current ship electric propulsion systems are mainly monopolized by foreign countries, or the core equipment relies on foreign imports. Large-scale marine pod motors lack corresponding performance test verification platforms. Even if the core equipment is independently developed, there is still a lack of test verification, and product performance optimization and upgrading cannot be achieved. The development of related technologies is slow. Summary of the invention

[0003] The purpose of the present invention is to provide a comprehensive test bench and test method for a large-scale marine pod power system, which can realize the performance test of large-scale marine pod motors with voltage levels ranging from 6.6kV, 11kV, and 13.8kV and power ranges below 11MW.

[0004] The present invention is achieved through the following technical solutions:

[0005] A comprehensive test bench for a large marine pod power system, comprising a transformer module, a drive module, a loading module, a control and monitoring station and a circulating water system, wherein the transformer module comprises two sets of high-voltage switches, a pre-magnetic transformer and a three-winding rectifier transformer, the output power of a three-phase switch control cabinet A is connected to the star winding input end of the three-winding rectifier transformer through the high-voltage switch and the pre-magnetic transformer in sequence, and the output power of a three-phase switch control cabinet B is connected to the delta winding input end of the three-winding rectifier transformer through the high-voltage switch;

[0006] The drive module includes a first drive unit and a second drive unit, the output end of the three-winding rectifier transformer is connected to the input end of the first drive unit, and the output end of the first drive unit is connected to the large marine pod motor being tested in the loading module through a switch wiring cabinet;

[0007] The shaft of the tested large-scale marine pod motor is connected to the first output shaft of the shaft-holding generator of the loading module through a coupling, the second output shaft of the shaft-holding generator is connected to the hydraulic dynamometer shaft through a coupling, and the output end of the shaft-holding generator is connected to one end of the second drive unit; the other end of the second drive unit is divided into three paths, the first path of direct current is fed back to the DC input end of the first drive unit through the first DC switch, the second path of direct current is directly input into the battery pack for charging and energy storage through the second DC switch, and the third path is alternating current fed back to the user for use of the load;

[0008] The control and monitoring platform includes an industrial computer, a PLC controller, a train clock and an AVL controller. The PLC controller communicates with the industrial computer via Ethernet and provides real-time feedback to the control and monitoring test platform on the corresponding voltage, current, speed and power performance parameters. The signal line of the AVL controller is electrically connected to the control end of the hydraulic dynamometer, and the signal line of the control and monitoring platform is electrically connected to the high-voltage switch and the control end of the shaft-holding generator respectively.

[0009] The circulating water system includes a water supply unit, a cooling unit and a circulating water pool. The water supply unit water pump inlet pipe and the cooling unit water pump inlet pipe lead to the circulating water pool respectively. The water supply unit water pump outlet pipe is connected to the water inlet end of the hydraulic dynamometer through the water supply unit electromagnetic water inlet valve. The water outlet end of the hydraulic dynamometer leads to the circulating water pool through the water supply unit electromagnetic return valve. The cooling unit water pump outlet pipe passes through the first drive unit and the second drive unit in sequence and then leads to the circulating water pool.

[0010] The purpose of the present invention can be further achieved by the following technical measures.

[0011] Furthermore, the first drive unit and the second drive unit of the drive module have the same structure, and respectively include a frequency converter, a voltage transformer, a current transformer and a brake resistor cabinet, each frequency converter output end is respectively connected to the corresponding voltage transformer, current transformer and brake resistor cabinet, the output end of the three-winding rectifier transformer is connected to the frequency converter input end of the first drive unit, and the current transformer of the second drive unit is connected to the large pod motor under test; the AC end of the second drive unit after inverter conversion by the frequency converter is connected to the user's load, the first DC end of the frequency converter of the second drive unit is connected to a battery pack for storing feedback electric energy through a first DC switch, and the first DC end of the frequency converter of the second drive unit is also connected to the second DC end of the first drive unit through a second DC switch, so as to feed energy back to the second DC end of the first drive unit;

[0012] The signal lines of the control and monitoring station are electrically connected to the frequency converter, resistance cabinet, current transformer and voltage transformer of the corresponding drive unit respectively;

[0013] The cooling unit water outlet pipe is connected to the frequency converter of the first drive unit, the frequency converter of the second drive unit, the brake resistor cabinet of the second drive unit, and the brake resistor cabinet of the first drive unit in sequence, and then leads to the circulating water pool.

[0014] Furthermore, the capacity of the three-winding rectifier transformer is: 11000kVA, 3-phase 3-wire, primary voltage: 13.8kV or 11kV or 6.6kV, secondary voltage: 2000V, frequency: 50Hz / 60Hz; the capacity of the pre-magnetizing transformer is: 3300kVA.

[0015] Furthermore, the inverter is a three-level AC-DC-AC inverter with a rated capacity of 11 MVA, diode rectification, IGBT power devices, input voltage of 2×2000 V, output voltage of 3AC 3000 V, and input frequency of 50 / 60 Hz.

[0016] Furthermore, the power range of the braking resistor cabinet is: 300-500kW, the voltage range is: 500-3000V, and the rated temperature rise is: 380°C.

[0017] Furthermore, the accuracy of the voltage transformer is: level 0.2, and the output voltage is ≤0.1 kV; the accuracy of the current transformer is: level 0.2, and the output current is ≤5 A.

[0018] A method for using a comprehensive test bench for a large-scale marine pod power system includes the following startup step A and shutdown step B;

[0019] Boot Step A:

[0020] A1) First, turn on the cooling unit of the circulating water system to cool the frequency converter and brake resistor cabinet corresponding to the first drive unit and the second drive unit; then send a signal through the control and monitoring station, and the high-voltage switch connecting the three-phase switch cabinet A and the pre-magnetic transformer is closed, and the pre-magnetic transformer is powered. One minute later, the high-voltage switch connecting the three-phase switch cabinet B and the three-winding rectifier transformer is closed, and the three-winding rectifier transformer is powered and works. At this time, the high-voltage switch connecting the three-phase switch cabinet A is disconnected, and the pre-magnetic transformer stops working;

[0021] A2) The inverter is powered, and a 4-20mA signal is sent to the inverter of the first drive unit through the car clock of the control and monitoring station. The output end of the inverter of the first drive unit controls the large marine pod motor under test through the corresponding current transformer and switch wiring cabinet to achieve continuous speed regulation of 0-150r / min, and conducts forward and reverse rotation test, speed measurement, voltage and current monitoring test;

[0022] A3) Start the water supply unit of the circulating water system, and according to the different speed loading curves set by the AVL controller of the control and monitoring station, automatically adjust the opening of the electromagnetic water inlet valve and the electromagnetic water return valve of the water supply unit of the hydraulic dynamometer through the output signal of the AVL controller, so as to realize the loading load adjustment test of the large marine pod motor to be tested, so as to simulate the propeller characteristics of the large marine pod motor;

[0023] A4) During the performance test of the large marine pod motor, the shaft-holding generator converts part of the energy into electrical energy, converts the AC power of different frequencies into DC power through the inverter of the second drive unit, closes the second DC switch through the control and monitoring station, and feeds the DC power back to the second DC terminal of the inverter of the first drive unit to realize energy feedback, or closes the first DC switch through the control and monitoring station to directly charge the battery pack to store energy; or directly converts the energy recovered by the shaft-holding generator into the required AC power through the inverter of the second drive unit, and provides it to the user for load heating or hot water electricity, thereby improving energy utilization;

[0024] Shutdown Step B:

[0025] B1) When shutting down, first cut off the DC switch corresponding to the energy recovery end of the inverter of the second drive unit, and reduce the speed of the large marine pod motor being tested to 25-35r / min through the signal sent by the car clock of the control and monitoring station;

[0026] B2) The electromagnetic return valve of the water supply unit is fully opened through the output signal of the AVL controller, and the water supply unit water pump is immediately turned off. Then, the large marine pod motor under test is slowly stopped by the signal sent by the car clock of the control and monitoring station, but the cooling unit water pump continues to run for more than 20 minutes to ensure effective heat dissipation of the inverter and brake resistor cabinet, and finally the cooling unit water pump is turned off.

[0027] The test bench of the present invention can realize the testing of various marine pod motors with multiple voltage levels and power ranges below 11MW, and has good versatility. The present invention adopts a shaft-clamped generator plus a frequency converter as an energy recovery system, which can realize three functions of energy feedback, energy storage and energy reuse, and has a significant energy-saving effect. The present invention adopts an AVL hydraulic dynamometer control system to load the marine pod motor to simulate the propulsion characteristics of the marine pod motor driving the propeller, thereby simplifying the test process of the marine pod motor to the greatest extent and improving the test efficiency of the marine pod motor. The test method of the present invention ensures the safety and reliability of the tested marine pod motor and the test bench.

[0028] Advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments thereof, which are given by way of example only with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings and embodiments of the present invention.

[0031] Figure 1 The double-dotted line frame represents the module, the thin solid line represents the strong electrical connection between the components in each module, the dotted line represents the weak electrical connection between the control and monitoring console and the components in each module, and the dotted line represents the connecting waterway.

[0032] like Figure 1 As shown, the comprehensive test bench for the power system of a large marine pod of the present invention includes a transformer module 1, a drive module 2, a loading module 3, a control and monitoring station 4 and a circulating water system 5. The transformer module 1 includes two sets of high-voltage switches 11, a pre-magnetic transformer 12 and a three-winding rectifier transformer 13. The output power of the three-phase electric switch control cabinet A6 is connected to the input end of the star winding 131 of the three-winding rectifier transformer 13 through the high-voltage switch 11 and the pre-magnetic transformer 12 in turn, and the output power of the three-phase electric switch control cabinet B7 is connected to the input end of the delta winding 132 of the three-winding rectifier transformer through the high-voltage switch 11. The high-voltage switch 11 of this embodiment is a VEP series AC high-voltage sealed vacuum circuit breaker, model: VEP-24 / 2500A-30kA.

[0033] The capacity of the three-winding rectifier transformer 13 is 11000 kVA, 3-phase 3-wire, primary voltage is 13.8 kV or 11 kV or 6.6 kV, secondary voltage is 2000 V, frequency is 50 Hz / 60 Hz. The capacity of the pre-magnetizing transformer 12 is 3300 kVA.

[0034] The drive module 2 includes a first drive unit 21 and a second drive unit 22. The first drive unit 21 and the second drive unit 22 of the drive module 2 have the same structure and respectively include a frequency converter 211, a voltage transformer 212, a current transformer 213 and a brake resistor cabinet 214. The output end of each frequency converter 211 is respectively connected to the corresponding voltage transformer 212, current transformer 213 and brake resistor cabinet 214. The output end of the three-winding rectifier transformer 13 is connected to the input end of the frequency converter 211 of the first drive unit 21. The current transformer 213 of the first drive unit 21 is connected to the large pod motor 10 under test through the switch wiring cabinet 5. The AC end AC of the second drive unit 22 after inversion by the frequency converter 211 is connected to the user load 20, the first DC end DC1 of the frequency converter 211 of the second drive unit 22 is connected to the battery pack 216 for storing feedback electric energy through the first DC switch 215, and the frequency converter 21 of the second drive unit 22 is also connected to the second DC end DC2 of the first drive unit 21 through the second DC switch 217, feeding back energy to the second DC end DC2 of the first drive unit 21. The other end of the second drive unit 22 is divided into three paths, one DC path is fed back to the first drive unit 21 through the second DC switch 217 of the second drive unit 22, another DC path is directly input into the battery pack 216 through the first DC switch 215 to charge and store energy, and the third path is AC, which is fed back to the user load 20 through the AC end AC.

[0035] The tested large marine pod motor shaft 101 is connected to the first output shaft 311 of the shaft-holding generator of the loading module 3 through the coupling 102, and the second output shaft 312 of the shaft-holding generator is connected to the hydraulic dynamometer shaft 321 through the coupling 102. The output end of the shaft-holding generator 31 is connected to the current transformer 213 at one end of the second drive unit 22.

[0036] The control and monitoring station 4 includes an industrial computer 41, a PLC controller 42, a car clock 43 and an AVL controller 44. The PLC controller 42 communicates with the industrial computer 41 via Ethernet and provides real-time feedback of the corresponding voltage, current, speed and power performance parameters to the control and monitoring test station 4. The signal line 45 of the AVL controller 44 is electrically connected to the control end of the hydraulic dynamometer 32. The signal line 45 of the control and monitoring station 4 is also electrically connected to the high-voltage switch 11, the control end of the shaft-holding generator 31 and the voltage transformer 212, current transformer 213 and brake resistor cabinet 214 corresponding to the two drive units.

[0037] The circulating water system 5 includes a water supply unit 51, a cooling unit 52 and a circulating water pool 53. The water supply unit water pump inlet pipe 512 and the cooling unit water pump inlet pipe 522 lead to the circulating water pool 53 respectively. The water supply unit water pump outlet pipe 513 is connected to the water inlet end of the hydraulic dynamometer 32 through the water supply unit electromagnetic water inlet valve 514. The water outlet end of the hydraulic dynamometer 32 leads to the circulating water pool 53 through the water supply unit electromagnetic water return valve 515. The cooling unit water pump outlet pipe 523 enters from the A port of the inverter 211 of the first drive unit 21 in sequence, then enters from the B port of the inverter 211 of the first drive unit 21 into the C port of the inverter 211 of the second drive unit 22, then is discharged from the D port of the inverter 211 of the second drive unit 22, then enters the braking resistor cabinet 214 of the second drive unit 22 and the braking resistor cabinet 214 of the first drive unit 21 in sequence, and then leads to the circulating water pool 53, so that the inverters 211 and the braking resistor cabinets 214 of the two drive units are cooled in time.

[0038] The water supply unit 51 injects water into the hydraulic dynamometer 32 according to the different speed loading curves set by the AVL controller 44 of the water injection control and monitoring station 4, thereby completing the loading test of the large marine pod motor 10 being tested.

[0039] The capacity of the three-winding rectifier transformer 13 is 11000kVA, 3-phase 3-wire, primary voltage: 13.8kV or 11kV or 6.6kV, secondary voltage: 2000V, frequency: 50Hz / 60Hz. The capacity of the pre-magnetic transformer 12 is 3300kVA.

[0040] The inverter 211 is a three-level AC-DC-AC inverter, with a rated capacity of 11 MVA, diode rectification, IGBT power devices, input voltage of 2×2000 V, output voltage of 3AC 3000 V, and input frequency of 50 / 60 Hz.

[0041] The power range of the brake resistor cabinet 214 is: 300-500kW, the voltage range is: 500-3000V, and the rated temperature rise is: 380℃.

[0042] The voltage transformer 212 of this embodiment is of model HJ12-15 with an accuracy of 0.2 and an output voltage of ≤0.1 kV; the current transformer 213 is of model HL28-19R with a precision of 0.2 and an output current of ≤5 A.

[0043] The test method of the large-scale marine pod power system comprehensive test bench includes the following startup step A and shutdown step B;

[0044] Boot Step A:

[0045] A1) First open the cooling unit 51 of the circulating water system 5 to cool the frequency converter 211 and the brake resistor cabinet 214 corresponding to the first drive unit 21 and the second drive unit 22. Then send a signal through the control and monitoring station 4, and the high-voltage switch 11 connecting the three-phase electric switch cabinet A6 and the pre-magnetizing transformer 12 is closed, and the pre-magnetizing transformer 12 is powered. One minute later, the high-voltage switch 11 connecting the three-phase electric switch cabinet B7 and the three-winding rectifier transformer 13 is closed, and the three-winding rectifier transformer 13 is powered and works. At this time, the high-voltage switch 11 connected to the three-phase electric switch cabinet A6 is disconnected, and the pre-magnetizing transformer 12 quits working. The pre-magnetizing transformer 13 pre-magnetizes the three-winding rectifier transformer 13 for 1 minute before starting the three-winding rectifier transformer 13, which can effectively prevent the large-capacity transformer from starting and the surge current from causing an impact on the power grid.

[0046] A2) The inverter 211 is powered, and sends 4-20 mA signals to the inverter 211 of the first drive unit 21 through the car clock 43 of the control and monitoring station 4. The output end of the inverter 211 of the first drive unit 21 controls the large marine pod motor 10 under test to achieve continuous speed regulation of 0-150 r / min through the corresponding current transformer 213 and the switch wiring cabinet 5, and performs forward and reverse rotation tests, speed measurement, and voltage and current monitoring tests.

[0047] A3) starting the water supply unit 51 of the circulating water system 5, and automatically adjusting the opening sizes of the water supply unit electromagnetic water inlet valve 514 and the water supply unit electromagnetic water return valve 51 of the hydraulic dynamometer 32 through the output signal of the AVL controller according to the different speed loading curves set by the AVL controller 42 of the control and monitoring station 4, so as to realize the loading load adjustment test of the tested large marine pod motor 10, so as to simulate the propeller characteristics of the large marine pod motor 10.

[0048] A4) During the performance test of the large-scale marine pod motor 10, the shaft-holding generator 31 converts a part of the energy into electrical energy, converts the alternating current of different frequencies into direct current through the inverter 211 of the second drive unit 22, sends a signal through the control and monitoring station 4 to close the second DC switch 217, and feeds the direct current back to the second DC terminal DC2 of the inverter 211 of the first drive unit 21 to realize energy feedback, or sends a signal through the control and monitoring station 4 to close the first DC switch 215 to directly charge the battery pack 216 to store energy, or directly converts the energy recovered by the shaft-holding generator 31 into the required alternating current through the inverter 211 of the second drive unit 22, and provides it to the user load 20 for heating or hot water through the AC terminal AC, thereby improving energy utilization.

[0049] Shutdown Step B:

[0050] B1) When shutting down, the DC switch corresponding to the energy recovery terminal of the frequency converter of the second drive unit 22 is first cut off, and the speed of the large marine pod motor 10 being tested is reduced to 25-35 r / min through the signal sent by the car clock 43 of the control and monitoring station 4.

[0051] B2) The electromagnetic return valve 515 of the water supply unit is fully opened by outputting a signal through the AVL controller 42, and the water supply unit water pump 511 is immediately closed. Then, the large marine pod motor 10 under test is slowly stopped by a signal sent by the car clock 43 of the control and monitoring station 4, but the cooling unit water pump 521 continues to run for more than 20 minutes, thereby ensuring that the drive equipment such as the inverter 211 and the brake resistor cabinet 214 effectively dissipates heat, and finally the cooling unit water pump 521 is closed.

[0052] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present invention.

Claims

1. A comprehensive test bench for large-scale marine pod power system, It is characterized in that It includes a transformer module, a drive module, a loading module, a control and monitoring station and a circulating water system. The transformer module includes two sets of high-voltage switches, a pre-magnetic transformer and a three-winding rectifier transformer. The output power of the three-phase switch control cabinet A is connected to the star winding input end of the three-winding rectifier transformer through the high-voltage switch and the pre-magnetic transformer in turn. The output power of the three-phase switch control cabinet B is electrically connected to the delta winding input end of the three-winding rectifier transformer through the high-voltage switch. The drive module includes a first drive unit and a second drive unit, the output end of the three-winding rectifier transformer is connected to the input end of the first drive unit, and the output end of the first drive unit is connected to the large marine pod motor being tested in the loading module through a switch wiring cabinet; The shaft of the tested large-scale marine pod motor is connected to the first output shaft of the shaft-holding generator of the loading module through a coupling, the second output shaft of the shaft-holding generator is connected to the hydraulic dynamometer shaft through a coupling, and the output end of the shaft-holding generator is connected to one end of the second drive unit; the other end of the second drive unit is divided into three paths, the first path of direct current is fed back to the DC input end of the first drive unit through the first DC switch, the second path of direct current is directly input into the battery pack through the second DC switch to charge and store energy, and the third path of alternating current is fed back to the user for use of the load; The control and monitoring platform includes an industrial computer, a PLC controller, a train clock and an AVL controller. The PLC controller communicates with the industrial computer via Ethernet and provides real-time feedback to the control and monitoring test platform on the corresponding voltage, current, speed and power performance parameters. The signal line of the AVL controller is electrically connected to the control end of the hydraulic dynamometer, and the signal line of the control and monitoring platform is electrically connected to the high-voltage switch and the control end of the shaft-holding generator respectively. The circulating water system comprises a water supply unit, a cooling unit and a circulating water pool, wherein the water supply unit water pump inlet pipe and the cooling unit water pump inlet pipe lead to the circulating water pool respectively, the water supply unit water pump outlet pipe is connected to the water inlet end of the hydraulic dynamometer through the water supply unit electromagnetic water inlet valve, and the water outlet end of the hydraulic dynamometer leads to the circulating water pool through the water supply unit electromagnetic water return valve; the cooling unit water pump outlet pipe leads to the circulating water pool after passing through the first drive unit and the second drive unit in sequence; The capacity of the three-winding rectifier transformer is 11000 kVA, 3-phase 3-wire, primary voltage is 13.8 kV or 11 kV or 6.6 kV, secondary voltage is 2000 V, frequency is 50 Hz / 60 Hz; the capacity of the pre-magnetizing transformer is 3300 kVA; The accuracy of the voltage transformer is 0.2 level, and the output voltage is ≤0.1 kV; the accuracy of the current transformer is 0.2 level, and the output current is ≤5 A.

2. The large-scale marine pod power system comprehensive test bench as claimed in claim 1, It is characterized in that The first drive unit and the second drive unit of the drive module have the same structure, and respectively include a frequency converter, a voltage transformer, a current transformer and a brake resistor cabinet. Each frequency converter output end is respectively connected to the corresponding voltage transformer, current transformer and brake resistor cabinet, the output end of the three-winding rectifier transformer is connected to the frequency converter input end of the first drive unit, and the current transformer of the second drive unit is connected to the large pod motor under test; the AC end of the second drive unit after inverter conversion by the frequency converter is connected to the user's load, the first DC end of the frequency converter of the second drive unit is connected to a battery pack for storing feedback electric energy through a first DC switch, and the first DC end of the frequency converter of the second drive unit is also connected to the DC end of the first drive unit through a second DC switch to feed energy back to the second DC end of the first drive unit; The signal lines of the control and monitoring station are electrically connected to the frequency converter, resistance cabinet, current transformer and voltage transformer of the corresponding drive unit respectively; The cooling unit water outlet pipe is connected to the frequency converter of the first drive unit, the frequency converter of the second drive unit, the brake resistor cabinet of the second drive unit, and the brake resistor cabinet of the first drive unit in sequence, and then leads to the circulating water pool; The accuracy of the voltage transformer is 0.2 level, and the output voltage is ≤0.1 kV; the accuracy of the current transformer is 0.2 level, and the output current is ≤5 A.

3. The large-scale marine pod power system comprehensive test bench as claimed in claim 2, It is characterized in that The inverter is a three-level AC-DC-AC inverter with a rated capacity of 11MVA, diode rectification, IGBT power devices, input voltage of 2×2000V, output voltage of 3AC 3000V, and input frequency of 50 / 60HZ.

4. The large-scale marine pod power system comprehensive test bench as claimed in claim 2, It is characterized in that The power range of the braking resistor cabinet is 300-500kW, the voltage range is 500-3000V, and the rated temperature rise is 380°C.

5. A test method for the large-scale marine pod power system comprehensive test bench as claimed in claim 1, It is characterized in that It includes the following startup step A and shutdown step B; Boot Step A: A1) First, turn on the cooling unit of the circulating water system to cool the inverter and brake resistor cabinet corresponding to the first drive unit and the second drive unit; then send a signal through the control and monitoring console, and the high-voltage switch connecting the three-phase switch cabinet A and the pre-magnetic transformer is closed, and the pre-magnetic transformer is powered. One minute later, the high-voltage switch connecting the three-phase switch cabinet B and the three-winding rectifier transformer is closed, and the three-winding rectifier transformer is powered and works. At this time, the high-voltage switch connecting the three-phase switch cabinet A is disconnected, and the pre-magnetic transformer stops working; A2) The inverter is powered, and a 4-20mA signal is sent to the inverter of the first drive unit through the car clock of the control and monitoring station. The output end of the inverter of the first drive unit controls the large marine pod motor under test through the corresponding current transformer and switch wiring cabinet to achieve continuous speed regulation of 0-150r / min, and conduct forward and reverse rotation test, speed measurement, voltage and current monitoring test; A3) Start the water supply unit of the circulating water system, and according to the different speed loading curves set by the AVL controller of the control and monitoring station, automatically adjust the opening of the electromagnetic water inlet valve and the electromagnetic water return valve of the water supply unit of the hydraulic dynamometer through the output signal of the AVL controller, so as to realize the loading load adjustment test of the large marine pod motor being tested, so as to simulate the propeller characteristics of the large marine pod motor; A4) During the performance test of large marine pod motors, the shaft-holding generator converts part of its energy into electrical energy, converts AC power of different frequencies into DC power through the inverter of the second drive unit, closes the second DC switch through the control and monitoring station, and feeds the DC power back to the second DC terminal of the inverter of the first drive unit to achieve energy feedback, or closes the first DC switch through the control and monitoring station to directly charge the battery pack to store energy; or directly converts the energy recovered by the shaft-holding generator into the required AC power through the inverter of the second drive unit, and provides it to users for load heating or hot water electricity, thereby improving energy utilization; Shutdown Step B: B1) When shutting down, first cut off the DC switch corresponding to the energy recovery end of the inverter of the second drive unit, and reduce the speed of the large marine pod motor being tested to 25-35r / min through the signal sent by the car clock of the control and monitoring station; B2) The electromagnetic return valve of the water supply unit is fully opened through the output signal of the AVL controller, and the water supply unit water pump is immediately turned off. Then, the large marine pod motor under test is slowly stopped by the signal sent by the car clock of the control and monitoring station, but the cooling unit water pump continues to run for more than 20 minutes to ensure effective heat dissipation of the inverter and the brake resistor cabinet, and finally the cooling unit water pump is turned off.

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