Control protection method of parallel power electronic equipment test system

Abstract

The invention relates to a control protection method for a parallel power electronic equipment test system, in particular to a control protection method for carrying out fault early warning on the parallel power electronic equipment test system according to load characteristics of tested equipment and allowable power of a parallel power electronic test device. The control protection method of the parallel power electronic equipment test system can be suitable for the parallel power electronic equipment test system, so that the parallel power electronic equipment test system reduces fault impact of a test device and tested equipment caused by partial abnormity of a test system module through fault early warning and control protection; the work efficiency of the test system and the service life of equipment are reduced.

Description

Technical Field

[0001] The present invention relates to the field of power electronic equipment control, and particularly to a control and protection method for a parallel power electronic equipment test system. Background Art

[0002] The power ratings of power electronic equipment such as energy storage converters and photovoltaic inverters increase year by year, and the requirements for the power rating of a parallel power electronic equipment test system are also getting higher and higher. Due to the limitations of the power device specifications, it is determined that the power rating of a single unit of a parallel power electronic equipment test system cannot be infinitely increased, and only power units can be paralleled to increase the overall power rating of the parallel power electronic equipment test system. The number of fault points in a parallel power electronic equipment test system is significantly more than that in a non-parallel power electronic equipment test system. Therefore, the stability of a parallel power electronic equipment test system is weaker than that of a non-parallel power electronic equipment test system.

[0003] When conducting abnormal large current test items (such as high and low voltage ride-through, overload, grid adaptability, etc.) on power electronic equipment, the test devices and the devices under test in a parallel power electronic equipment test system stop operating disorderly, which not only reduces the test efficiency, but also shortens the service life of the test devices and the devices under test, and parallel operation is very likely to cause damage to the test devices and the devices under test. By adopting the present control and protection method, the fault impact on the test devices and the devices under test caused by the abnormality of the module part of the parallel power electronic equipment test system can be effectively reduced, and the loss of the working efficiency and equipment life of the parallel power electronic equipment test system can be avoided.

[0004] Therefore, aiming at the deficiencies of the prior art, it is very necessary to provide a control and protection method for a parallel power electronic equipment test system to solve the deficiencies of the prior art. Summary of the Invention

[0005] The purpose of the present invention is to provide a control and protection method for a parallel power electronic equipment test system to avoid the deficiencies of the prior art. The control and protection method for the parallel power electronic equipment test system can be applied to a parallel power electronic power test system, enabling the parallel power electronic power test system to reduce the loss of the working efficiency and equipment life of the test system caused by the fault impact on the test devices and the devices under test due to the abnormality of the module part of the test system through fault early warning and control and protection.

[0006] The above object of the present invention is achieved by the following technical measures:

[0007] A control and protection method for a parallel-type power electronic equipment test system, which is a control and protection method for fault early warning of a parallel-type power electronic equipment test system according to the load characteristics of the equipment under test and the allowable power of the parallel-type power electronic test device; wherein the parallel-type power electronic equipment test system is provided with the equipment under test and the parallel-type power electronic test device.

[0008] The parallel-type power electronic test device is a separate AC test device, a separate DC test device, and an AC-DC test device; wherein the AC-DC test device is composed of an AC test device and a DC test device.

[0009] The AC test device includes parallel and independently operable AC minimum power units, wherein the grid side is connected in parallel to the external power grid, and the machine side is connected in parallel to the equipment under test.

[0010] The DC test device includes parallel and independently operable DC minimum power units, wherein the grid side is connected in parallel to the external power grid, and the machine side is connected in parallel to the equipment under test.

[0011] Preferably, the load characteristics of the above-mentioned equipment under test are calculated by formula (1);

[0012] P load (t 1 )≤P m ,t m-1 <t 1 ≤t m ……Formula (1);

[0013] Wherein, P load (t 1 ) is the load power, m is a fixed parameter determined by the detection item and m is a non-zero natural number, P m is a fixed parameter determined by the detection item and P m is the maximum load power corresponding to t m-1 to t m time, t 1 is the test running time of the equipment under test in the parallel-type power electronic equipment test system; t m is the running time for the equipment under test to complete the detection item and t m is a fixed parameter determined by the detection item, t m-1 is the cut-off time for the load power P m-1 to run at power.

[0014] Preferably, the maximum allowable power of the above-mentioned AC test device is represented by formula (2);

[0015] P AC_source (t 2 )=P AC_source_unit (t 2)×x AC ……Equation (2);

[0016] Wherein, P AC_source_unit (t 2 ) is the maximum allowable power of the AC minimum power unit, x AC is the number of AC minimum power units for the normal operation of the AC test device, t 2 is the longest operation time of P AC_source_unit (t 2 ).

[0017] Preferably, the above maximum allowable power P AC_source_unit (t 2 ) is represented by Equation (3):

[0018]

[0019] Wherein n1, P AC_n1 and t AC_n1 are all fixed parameters of the AC test device, where n1 is a non-zero natural number, and t AC_1 is the longest allowable time for the AC source at a power of P AC_1 .

[0020] Preferably, the maximum allowable power of the above DC test device is represented by Equation (4);

[0021] P DC_source (t 3 ) = P DC_source_unit (t 3 ) × x DC ……Equation (4);

[0022] Wherein, P DC_source_unit (t 3 ) is the maximum allowable power of the DC minimum power unit; x AC is the number of DC minimum power units for the normal operation of the DC test device, and t 3 is the longest operation time of P DC_source_unit (t 3 ).

[0023] Preferably, the above maximum allowable power P DC_source_unit (t 3 ) is represented by Equation (5):

[0024]

[0025] Wherein, n2, P DC_n2 and t DC_n2 are all fixed parameters of the DC test device, and n2 is a non-zero natural number, and t DC_1 is the longest allowable time for the DC source at a power of P DC_1The longest allowable time, t DC_(n2-1) is the direct current source with power P DC_(n2-1) The longest allowable time.

[0026] Preferably, the maximum allowable power of the above AC-DC test device is represented by Equation (6):

[0027]

[0028] where P AC&DC_source (t) is the maximum allowable power of the AC-DC test device.

[0029] In a separate AC-type test device, it is carried out according to the following steps:

[0030] A1. Determine whether the device under test has completed the test items: Let the test running time t of the device under test 1 = t 0 , and t 0 is the actual test running time of the device under test and t 0 is a constant, then compare t 0 with t m . When t 0 < t m , it means that the detection item is not completed and enter A2; when t 0 ≥ t m it means that the test item is completed and enter A4;

[0031] A2. Predict the load of the device under test: Compare t 0 and t 1 , ……, t m respectively, determine the time period of the load of the device under test on the load characteristic curve when t 0 , and make t k-1 ≤ t 0 < t k , k is a non-zero natural number and k < m, where k is determined by t 0 and the load characteristic P load (t 1 ). The start and end times of the load power corresponding to the time t 0 are t k-1 to t k ; Obtain the predicted load of the device under test at the test time t load (t 1 ) according to the load characteristic P 0 < t 1 ≤ t m as Then enter A3;

[0032] A3. Early warning judgment of the AC-type test device: Compare the predicted load P of the device under testload (t 1 ) and the maximum allowable power P of the AC test device AC_source (t 2 ); when the predicted load P of the device under test load (t 1 ) is greater than the maximum allowable power P of the AC test device AC_source (t 2 ), that is and do not hold, then return A5; when the predicted load P of the device under test load (t 1 ) is less than or equal to the maximum allowable power P of the AC test device AC_source

[0033] (t 2 ), that is and hold, then return A1, where P k is the power of the predicted load of the device under test at time t k-1 to t k , and P m is the power of the predicted load of the device under test at time t m-1 to t m ;

[0034] A4. Send a test normal completion message to the parallel power electronic device test system, send a shutdown command to the device under test, and send a shutdown command to the AC test device after the device under test shuts down;

[0035] A5. Send a test device fault warning message to the parallel power electronic device test system, send a shutdown command to the device under test, and send a shutdown command to the AC test device after the device under test shuts down.

[0036] In a separate DC test device, proceed as follows:

[0037] B1. Determine whether the device under test has completed the test items: Let the test running time t of the device under test 1 = t 0 , and t 0 is the actual test running time of the device under test and t 0 is a constant. Then compare the magnitudes of t 0 and t m . When t 0 < t m , it means the test items are not completed and proceed to B2; when t 0 ≥ t m , it means the test items are completed and proceed to B4;

[0038] B2. Predict the load of the device under test: Compare \(t\) 0 and \(t\) 1 ,..., \(t\) m to determine the time period of the load of the device under test on the load characteristic curve at \(t\) 0 , and make \(t\) k-1 ≤ \(t\) 0 < \(t\) k , where \(k\) is a non - zero natural number and \(k\lt m\), and \(k\) is a constant determined by \(t\) 0 and the load characteristic \(P\) load \((t\) 1 ). Obtain the predicted load of the device under test at the test time \(t\) load \((t\) 1 ) according to the load characteristic \(P\) 0 < \(t\) 1 ≤ \(t\) m as Then enter A3;

[0039] B3. Warning judgment of the DC - type test device: Compare the predicted load \(P\) load \((t\) 1 ) of the device under test with the maximum allowable power \(P\) DC_source \((t\) 3 ) of the DC - type test device; When the predicted load \(P\) load \((t\) 1 ) of the device under test is greater than the maximum allowable power \(P\) DC_source \((t\) 3 ) of the DC - type test device, that is, and do not hold, then return to B5; When the predicted load \(P\) load \((t\) 1 ) of the device under test is less than or equal to the maximum allowable power \(P\) DC_source \((t\) 3 ) of the DC - type test device, that is, and hold, then return to B1;

[0040] B4. Send a message indicating that the test is completed normally to the parallel - type power electronic device test system, send a shutdown command to the device under test, and send a shutdown command to the DC - type test device after the device under test shuts down;

[0041] B5. Send a warning message about the test device failure to the series - parallel - type power electronic device test system, send a shutdown command to the device under test, and send a shutdown command to the DC - type test device after the device under test shuts down.

[0042] In the AC - DC test device, perform the following steps:

[0043] C1. Determine whether the device under test has completed the test items: Let the test running time of the device under test be t 1 = t 0 , and t 0 is the actual test running time of the device under test and t 0 is a constant. Then compare t 0 with t m . When t 0 < t m , it means that the test item is not completed and proceed to C2; when t 0 ≥ t m , it means that the test item is completed and proceed to C5;

[0044] C2. Predict the load of the device under test: Compare t 0 and t 1 , ……, t m respectively to determine the time period of the load of the device under test on the load characteristic curve when t 0 , and make t k-1 ≤ t 0 < t k , where k is a non - zero natural number and k < m, and k is determined by t 0 and the load characteristic P load (t 1 ). According to the load characteristic P load (t 1 ), obtain the predicted load of the device under test at the test time t 0 < t 1 ≤ t m as Then proceed to C3;

[0045] C3. Early warning judgment of the AC - type test device in the AC - DC type test device: Compare the predicted load P load (t 1 ) of the device under test with the maximum allowable power P AC_source (t 2 ) of the AC - type test device in the AC - DC type test device; When the predicted load P load (t 1 ) of the device under test is greater than the maximum allowable power P AC_source (t 2 ) of the AC - type test device in the AC - DC type test device, that is and do not hold, then return to C6; When the predicted load P load (t 1 ) of the device under test is less than or equal to the maximum allowable power P AC_source (t 2 ) of the AC - type test device in the AC - DC type test device, that is and If it holds, return C4;

[0046] C4. For the early warning judgment of the DC test device in the AC-DC test device: Compare the predicted load P load (t 1 ) of the device under test with the maximum allowable power P DC_source (t 3 ) of the DC test device in the AC-DC test device; When the predicted load P load (t 1 ) of the device under test is greater than the maximum allowable power P DC_source (t 3 ) of the DC test device in the AC-DC test device, that is and if it does not hold, return C7; When the predicted load P load (t 1 ) of the device under test is less than or equal to the maximum allowable power P DC_source (t 3 ) of the DC test device in the AC-DC test device, that is and if it holds, return C1;

[0047] C5. Send a test normal completion message to the parallel power electronic equipment test system, send a stop instruction to the device under test, and send a stop instruction to the AC-DC test device after the device under test stops.

[0048] C6. Send an AC test device fault warning message to the parallel power electronic equipment test system, send a stop instruction to the device under test, and send a stop instruction to the AC-DC test device after the device under test stops;

[0049] C7. Send a DC test device fault warning message to the parallel power electronic equipment test system, send a stop instruction to the device under test, and send a stop instruction to the AC-DC test device after the device under test stops.

[0050] A control and protection method for a parallel-type power electronic equipment test system according to the present invention is a control and protection method for fault warning of the parallel-type power electronic equipment test system based on the load characteristics of the equipment under test and the allowable power of the parallel-type power electronic test device. The parallel-type power electronic equipment test system is provided with the equipment under test and the parallel-type power electronic test device. The parallel-type power electronic test device is a separate AC test device, a separate DC test device, and an AC-DC test device. The AC-DC test device is composed of an AC test device and a DC test device. The AC test device includes parallel and independently operable AC minimum power units, where the grid side is connected in parallel to the external power grid and the machine side is connected in parallel to the equipment under test. The DC test device includes parallel and independently operable DC minimum power units, where the grid side is connected in parallel to the external power grid and the machine side is connected in parallel to the equipment under test. When conducting test items with abnormal large currents in power electronic equipment, such as high and low voltage ride-through, overload, grid adaptability, etc., the test devices and the equipment under test in the test system malfunction and shut down disorderly, which not only reduces the test efficiency but also shortens the service life of the test devices and the equipment under test. Parallel operation is extremely likely to cause damage to the test devices and the equipment under test. By using the control and protection method of the parallel-type power electronic equipment test system according to the present invention, the fault impact on the test devices and the equipment under test caused by the abnormality of the test system module part can be effectively reduced, and the loss of the working efficiency of the test system and the equipment life can be avoided. This control and protection method for the parallel-type power electronic equipment test system can be applied to the parallel-type power electronic power test system, enabling the parallel-type power electronic power test system to reduce the fault impact on the test devices and the equipment under test caused by the abnormality of the test system module part through fault warning and control protection, and avoiding the loss of the working efficiency of the test system and the equipment life. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The present invention will be further described with reference to the accompanying drawings, but the content in the drawings does not constitute any limitation to the present invention.

[0052] Figure 1 It is a flowchart of a control and protection method for a parallel-type power electronic equipment test system.

[0053] Figure 2 It is a schematic diagram of the application scenario of a separate AC test device.

[0054] Figure 3 It is a schematic diagram of the application scenario of a separate DC test device.

[0055] Figure 4 It is a schematic diagram of the application scenario of an AC-DC test device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] The technical solution of the present invention will be further described in conjunction with the following embodiments.

[0057] Example 1

[0058] A control and protection method for a parallel-type power electronic equipment test system, as Figure 1 , a control and protection method for fault early warning of a parallel-type power electronic equipment test system according to the load characteristics of the equipment under test and the allowable power of the parallel-type power electronic test device; wherein the parallel-type power electronic equipment test system is provided with the equipment under test and the parallel-type power electronic test device.

[0059] The parallel-type power electronic test device is a separate AC-type test device, a separate DC-type test device, and an AC-DC type test device.

[0060] As Figure 2 , the AC-type test device includes parallel and independently operable AC minimum power units, where the grid side is connected in parallel to the external power grid and the machine side is connected in parallel to the equipment under test.

[0061] As Figure 3 , the DC-type test device includes parallel and independently operable DC minimum power units, where the grid side is connected in parallel to the external power grid and the machine side is connected in parallel to the equipment under test.

[0062] Among them, the AC-DC type test device is composed of an AC-type test device and a DC-type test device, as Figure 4 .

[0063] It should be noted that in the AC-DC type test device, the AC-type test device is the same as the separate AC-type test device, and the DC-type test device is the same as the separate DC-type test device.

[0064] The load characteristics of the equipment under test are calculated by Equation (1);

[0065] P load (t 1 ) ≤ P m , t m-1 < t 1 ≤ t m ... Equation (1);

[0066] Among them, P load (t 1 ) is the load power, m is a fixed parameter determined by the detection item and m is a non-zero natural number, P m is a fixed parameter determined by the detection item and P m is the maximum load power corresponding to the time from t m-1 to t m , t 1 is the test running time of the equipment under test in the parallel-type power electronic equipment test system; t mThe running time for the device under test to complete the test items, and t m Fixed parameters determined by the test items, t m-1 Is the load power P m-1 The cut-off time for power operation.

[0067] It should be noted that the load characteristics of the device under test in Equation (1) represent the running time t of the device under test 1 At t m-1 To t m During the time period, the load power P load (t 1 ) is less than or equal to P m .

[0068] The maximum allowable power of the AC type test device is represented by Equation (2);

[0069] P AC_source (t 2 ) = P AC_source_unit (t 2 ) × x AC …… Equation (2);

[0070] Wherein, P AC_source_unit (t 2 ) is the maximum allowable power of the AC minimum power unit, x AC Is the number of AC minimum power units for the normal operation of the AC type test device, t 2 Is P AC_source_unit (t 2 ) The longest running time.

[0071] It should be noted that the maximum allowable power of the AC type test device in Equation (2) represents that the longest running time of the maximum allowable power P AC_source (t 2 ) does not exceed t 2 .

[0072] The maximum allowable power P AC_source_unit (t 2 ) is represented by Equation (3):

[0073]

[0074] Where n1, P AC_n1 And t AC_n1 Are all fixed parameters of the AC type test device, where n1 is a non-zero natural number, t AC_1 Is the longest allowable time for the AC source with a power of P AC_1 .

[0075] It should be noted that Equation (3) represents the maximum allowable power P AC_source_unit (t 2The maximum allowable power P of the AC minimum power unit AC_n1 has a maximum running time not exceeding t AC_n1 .

[0076] The maximum allowable power of the DC type test device is represented by Equation (4);

[0077] P DC_source (t 3 ) = P DC_source_unit (t 3 ) × x DC …… Equation (4);

[0078] Where, P DC_source_unit (t 3 ) is the maximum allowable power of the DC minimum power unit; x AC is the number of DC minimum power units for the normal operation of the DC type test device, and t 3 is the maximum running time of P DC_source_unit (t 3 ).

[0079] It should be noted that Equation (4) indicates that the maximum running time of the maximum allowable power P DC_source (t 3 ) of the DC type test device does not exceed t 3 .

[0080] The maximum allowable power P DC_source_unit (t 3 ) is represented by Equation (5):

[0081]

[0082] Where, n2, P DC_n2 and t DC_n2 are all fixed parameters of the DC type test device, and n2 is a non-zero natural number, and t DC_1 is the maximum allowable time for the DC power supply at a power of P DC_1 , and t DC_(n2-1) is the maximum allowable time for the DC power supply at a power of P DC_(n2-1) .

[0083] It should be noted that Equation (4) indicates that the maximum running time of the maximum allowable power P DC_source_unit (t 3 ) of the DC minimum power unit does not exceed t DC_n2 . DC_n2 .

[0084] The maximum allowable power of the AC-DC test device is represented by Equation (6):

[0085]

[0086] Among them, P AC&DC_source (t) is the maximum allowable power of the AC-DC test device.

[0087] It should be noted that in the AC-DC test device, the calculation methods of the maximum allowable power of the AC test device and the DC test device are the same as those of a single AC test device and a single DC test device.

[0088] In a single AC test device, it is carried out according to the following steps:

[0089] A1. Determine whether the device under test has completed the test items: Let the test running time of the device under test be t 1 = t 0 , and t 0 is the actual test running time of the device under test and t 0 is a constant. Then compare t 0 with t m . When t 0 < t m , it means that the detection item has not been completed and proceed to A2; when t 0 ≥ t m it means that the test item has been completed and proceed to A4;

[0090] A2. Predict the load of the device under test: Compare t 0 and t 1 , ……, t m respectively to determine the time period of the load of the device under test on the load characteristic curve when t 0 , and make t k-1 ≤ t 0 < t k , where k is a non-zero natural number and k < m, and k is a constant determined by t 0 and the load characteristic P load (t 1 ). The start and end times of the load power corresponding to the moment t 0 are t k-1 to t k ; Obtain the predicted load of the device under test during the test time t load (t 1 ) according to the load characteristic P 0 < t 1 ≤ t m as Then proceed to A3;

[0091] A3. Early warning judgment of the AC test device: Compare the predicted load P load (t 1 ) of the device under test with the maximum allowable power P of the AC test deviceAC_source (t 2 )'s magnitude; when the predicted load P of the device under test load (t 1 ) is greater than the maximum allowable power P of the AC type test device AC_source (t 2 ), that is and is not established, then return A5; when the predicted load P of the device under test load (t 1 ) is less than or equal to the maximum allowable power P of the AC type test device AC_source

[0092] (t 2 ), that is and is established, then return A1, where P k is the power of the predicted load of the device under test at time t k-1 to t k , and P m is the power of the predicted load of the device under test at time t m-1 to t m ;

[0093] A4. Send a test normal completion message to the parallel type power electronic device test system, send a shutdown command to the device under test, and send a shutdown command to the AC type test device after the device under test shuts down;

[0094] A5. Send a test device fault warning message to the parallel type power electronic device test system, send a shutdown command to the device under test, and send a shutdown command to the AC type test device after the device under test shuts down.

[0095] In a separate DC type test device, proceed as follows:

[0096] B1. Determine whether the device under test has completed the test items: Let the test running time t of the device under test 1 = t 0 , and t 0 is the actual test running time of the device under test and t 0 is a constant, then compare the magnitudes of t 0 and t m . When t 0 < t m , it means the test items are not completed and proceed to B2; when t 0 ≥ t m , it means the test items are completed and proceed to B4;

[0097] B2. Predict the load of the device under test: Compare t 0 and t 1 , ……, t mDetermine t based on the size of 0 the time period when the load of the device under test is on the load characteristic curve, and make t k-1 ≤t 0 <t k , where k is a non - zero natural number and k < m, and k is determined by t 0 and the load characteristic P load (t 1 ). According to the load characteristic P load (t 1 ) of the device under test, obtain the predicted load of the device under test at the test time t 0 <t 1 ≤t m as Then enter A3;

[0098] B3. Early warning judgment of DC - type test device: Compare the predicted load P load (t 1 ) of the device under test with the maximum allowable power P DC_source (t 3 ) of the DC - type test device; when the predicted load P load (t 1 ) of the device under test is greater than the maximum allowable power P DC_source (t 3 ) of the DC - type test device, that is, and do not hold, then return to B5; when the predicted load P load (t 1 ) of the device under test is less than or equal to the maximum allowable power P DC_source (t 3 ) of the DC - type test device, that is, and hold, then return to B1;

[0099] B4. Send a test normal completion message to the parallel - type power electronic equipment test system, send a shutdown command to the device under test, and send a shutdown command to the DC - type test device after the device under test shuts down;

[0100] B5. Send a test device failure early warning message to the series - parallel - type power electronic equipment test system, send a shutdown command to the device under test, and send a shutdown command to the DC - type test device after the device under test shuts down.

[0101] In the AC - DC type test device, proceed as follows:

[0102] C1. Determine whether the device under test has completed the test items: Let the test running time t 1 =t 0 , and t 0 is the actual test running time of the device under test and t0 is a constant, and then compare t 0 with t m For their magnitudes. When t 0 < t m it means the test item is not completed and enter C2; when t 0 ≥ t m it means the test item is completed and enter C5;

[0103] C2. Predict the load of the device under test: Compare t 0 and t 1 ,..., t m to determine the time period of the load of the device under test on the load characteristic curve when t 0 and make t k-1 ≤ t 0 < t k , where k is a non - zero natural number and k < m, and k is determined by t 0 and the load characteristic P load (t 1 ). According to the load characteristic P load (t 1 ) of the device under test, obtain the predicted load of the device under test at the test time t 0 < t 1 ≤ t m as Then enter C3;

[0104] C3. Early warning judgment of the AC - type test device in the AC - DC type test device: Compare the predicted load P load (t 1 ) of the device under test with the maximum allowable power P AC_source (t 2 ) of the AC - type test device in the AC - DC type test device; When the predicted load P load (t 1 ) of the device under test is greater than the maximum allowable power P AC_source (t 2 ) of the AC - type test device in the AC - DC type test device, that is and do not hold, then return to C6; When the predicted load P load (t 1 ) of the device under test is less than or equal to the maximum allowable power P AC_source (t 2 ) of the AC - type test device in the AC - DC type test device, that is and hold, then return to C4;

[0105] C4. Early warning judgment of the DC test device in the AC / DC test device: Compare the predicted load P of the device under test load (t 1 ) with the maximum allowable power P of the DC test device in the AC / DC test device DC_source (t 3 ). When the predicted load P of the device under test load (t 1 ) is greater than the maximum allowable power P of the DC test device in the AC / DC test device DC_source (t 3 ), that is and do not hold, then return to C7; when the predicted load P of the device under test load (t 1 ) is less than or equal to the maximum allowable power P of the DC test device in the AC / DC test device DC_source (t 3 ), that is and hold, then return to C1;

[0106] C5. Send a test normal completion message to the parallel power electronic equipment test system, send a shutdown command to the device under test, and send a shutdown command to the AC / DC test device after the device under test shuts down.

[0107] C6. Send an AC test device fault warning message to the parallel power electronic equipment test system, send a shutdown command to the device under test, and send a shutdown command to the AC / DC test device after the device under test shuts down;

[0108] C7. Send a DC test device fault warning message to the parallel power electronic equipment test system, send a shutdown command to the device under test, and send a shutdown command to the AC / DC test device after the device under test shuts down.

[0109] When conducting test items of abnormal large current in power electronic equipment, such as high and low voltage crossing, overload, grid adaptability, etc., the test devices and the devices under test in the test system malfunction and shut down disorderly, which not only reduces the test efficiency, but also shortens the service life of the test devices and the devices under test. Parallel operation is very likely to cause damage to the test devices and the devices under test. The control and protection method of the parallel-type power electronic equipment test system of the present invention can effectively reduce the fault impact on the test devices and the devices under test caused by the abnormality of the module part of the test system, and the loss of the working efficiency of the test system and the equipment life. The control and protection method of the parallel-type power electronic equipment test system can be applied to the parallel-type power electronic power test system, enabling the parallel-type power electronic power test system to reduce the fault impact on the test devices and the devices under test caused by the abnormality of the module part of the test system through fault early warning and control and protection, and the loss of the working efficiency of the test system and the equipment life.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A control and protection method for a parallel power electronic equipment test system, characterized in that: A control and protection method for providing fault warning to a parallel power electronic equipment test system according to the load characteristics of the equipment under test and the allowable power of the parallel power electronic test device; The parallel power electronic equipment test system is provided with a device under test and a parallel power electronic test device; The parallel power electronic test device is a separate AC test device, a separate DC test device and an AC / DC test device; the AC / DC test device is composed of an AC test device and a DC test device; The AC test device comprises AC minimum power units connected in parallel and capable of operating independently, wherein the grid side is connected in parallel to an external power grid, and the machine side is connected in parallel to a device under test; The DC test device comprises DC minimum power units which are connected in parallel and can operate independently, wherein the grid side is connected in parallel to an external power grid, and the machine side is connected in parallel to a device under test.

2. The control and protection method for a parallel power electronic equipment test system according to claim 1, characterized in that: The load characteristics of the equipment under test are calculated by formula (1); P load P ≥ (t1) m , t m-1 where t < t1 ≤ t m …… Equation (1); Among them, P load (t1) is the load power, m is a fixed parameter determined by the test item and m is a non-zero natural number, P m The fixed parameters determined for the test items and P m t m-1 to m time, t1 is the test running time of the device under test in the parallel power electronic equipment test system; t m is the running time of the device under test to complete the test items and t m Fixed parameters determined by the test project, t m-1 is the load power P m-1 Cut-off time for power operation.

3. The control and protection method for a parallel power electronic equipment test system according to claim 2, characterized in that: The maximum allowable power of the AC test device is expressed by formula (2); P AC_source (t2) = P AC_source_unit (t2)×x AC ...Formula (2); Among them, P AC_source_unit (t2) is the maximum allowable power of the AC minimum power unit, x aC is the minimum number of AC power units for normal operation of the AC test device, t2 is P AC_source_unit (t2) Maximum running time.

4. The control and protection method for a parallel power electronic equipment test system according to claim 3, characterized in that: The maximum permissible power P AC_source_unit (t2) is expressed by formula (3): Where n1, P AC_n1 and t aC_n1 These are fixed parameters of the AC test device, where n1 is a non-zero natural number, t AC_1 The AC source is P AC_1 The maximum allowed time.

5. The control and protection method for a parallel power electronic equipment test system according to claim 4, characterized in that: The maximum allowable power of the DC test device is expressed by formula (4); P DC_source (t3) = P DC_source_unit (t3)×x DC ...Formula (4); Among them, P DC_source_unit (t3) is the maximum allowable power of the DC minimum power unit; x AC is the minimum number of DC power units for normal operation of the DC test device, t3 is P DC_source_unit (t3) Maximum running time.

6. The control and protection method for a parallel power electronic equipment test system according to claim 5, characterized in that: The maximum permissible power P DC_source_unit (t3) is expressed by formula (5): Among them, n2, P DC_n2 and t DC_n2 are fixed parameters of the DC test device, and n2 is a non-zero natural number, t DC_1 The DC source has a power of P DC_1 The maximum allowed time, t DC_(n2-1) For a DC source with power P DC_(n2-1) The maximum allowed time.

7. The control and protection method for a parallel power electronic equipment test system according to claim 6, characterized in that: The maximum allowable power of the AC / DC test device is expressed by formula (6): Among them, P AC&DC_source (t) is the maximum allowable power of the AC and DC test equipment.

8. The control and protection method for a parallel power electronic equipment test system according to claim 7, characterized in that: Proceed as follows in a separate AC test setup: A1. Determine whether the device under test has completed the test item: Let the test running time of the device under test t1 = t0, and t0 is the actual test running time of the device under test and t0 is a constant, then compare t0 with t m The size of <t m When t0≥t m It means the test item is completed and enters A4; A2. Predict the load of the device under test: Compare the magnitudes of t0 and t1, …, t m respectively, determine the time period of the load of the device under test at t0 on the load characteristic curve, and make t k-1 ≤t0<t k , where k is a non - zero natural number and k < m, and k is a constant determined by t0 and the load characteristic P load (t1), where the start and end times of the load power corresponding to the moment t0 are t k-1 to t k ; Obtain the predicted load of the device under test at the test time t0 < t1 ≤ t 1oad according to the load characteristic P m (t1) as Then enter A3; A3. Early warning judgment of AC test device: Compare the predicted load of the equipment under test P load (t1) and the maximum allowable power P of the AC test device AC_source (t2) size; when the predicted load P of the equipment under test load (t1) is greater than the maximum allowable power P of the AC test device A-_source (t2), that is and If not, return to A5; when the predicted load P of the equipment under test load (t1) is less than or equal to the maximum allowable power P of the AC test device AC_source (t2), that is and If true, return A1, where P k Predict the load of the equipment under test at time t k-1 to k Power, P m Predict the load of the equipment under test at time t m-1 to m Power; A4. Send the test normal completion information to the parallel power electronic equipment test system, send a shutdown command to the device under test, and after the device under test is shut down, send a shutdown command to the AC test device; A5. Send the test device fault warning information to the parallel power electronic equipment test system, send a shutdown command to the equipment under test, and after the equipment under test is shut down, send a shutdown command to the AC test device.

9. The control and protection method for a parallel power electronic equipment test system according to claim 8, characterized in that: In a separate DC test setup, proceed as follows: B1. Determine whether the device under test has completed the test item: Let the test running time of the device under test t1 = t0, and t0 is the actual test running time of the device under test and t0 is a constant, then compare t0 with t m The size of <t m When t0≥t m It means the test item is completed and enters B4; B2. Predict the load of the device under test: Compare the magnitudes of t0 and t1, …, t m respectively, determine the time period of the load of the device under test at t0 on the load characteristic curve, and make t k-1 ≤ t0 < t k , where k is a non - zero natural number and k < m, and k is a constant determined by t0 and the load characteristic P load (t1). Obtain the predicted load of the device under test at the test time t0 < t1 ≤ t load according to the load characteristic P m (t1) as Then proceed to A3; B3. Early warning judgment of DC test device: Compare the predicted load P of the tested equipment load (t1) and the maximum allowable power P of the DC test device DC_source (t3); when the predicted load P of the equipment under test load (t1) is greater than the maximum allowable power P of the DC test device DC_source (t3), that is and If not, return to B5; when the predicted load P of the equipment under test load (t1) is less than or equal to the maximum allowable power P of the DC test device DC_source (t3), that is and If true, return to B1; B4. Send the test normal completion information to the parallel power electronic equipment test system, send a shutdown command to the device under test, and after the device under test is shut down, send a shutdown command to the DC test device; B5. Send the fault warning information of the test device to the direct parallel type power electronic equipment test system, send a shutdown command to the equipment under test, and after the equipment under test is shut down, send a shutdown command to the DC type test device.

10. The control and protection method for a parallel power electronic equipment test system according to claim 8, characterized in that: In the AC / DC type test device, the following steps are performed: C1. Determine whether the device under test has completed the test item: Let the test running time of the device under test t1 = t0, and t0 is the actual test running time of the device under test and t0 is a constant, then compare t0 with t m The size of <t m When t0≥t m It means the test item is completed and enters C5; C2. Predict the load of the device under test: Compare the magnitudes of t0 and t1, …, t m respectively, determine the time period on the load characteristic curve where the load of the device under test is located at t0, and make t k-1 ≤ t0 < t k , where k is a non - zero natural number and k < m, and k is a constant determined by t0 and the load characteristic P load (t1). Obtain the predicted load of the device under test at the test time t0 < t1 ≤ t load according to the load characteristic P m (t1) as Then proceed to C3; C3. Early warning judgment of the AC type test device in the AC / DC type test device: Compare the predicted load P of the tested equipment load (t1) is equal to the maximum allowable power P of the AC type test device in the AC / DC type test device AC_source (t2) size; when the predicted load P of the equipment under test load (t1) is greater than the maximum allowable power P of the AC type test device in the AC / DC type test device AC_source (t2), that is and If not, return to C6; when the predicted load P of the equipment under test load (t1) is less than or equal to the maximum allowable power P of the AC type test device in the AC / DC type test device AC_source (t2), that is and If true, return to C4; C4. Early warning judgment of the DC test device in the AC / DC test device: Compare the predicted load P of the tested equipment load (t1) is equal to the maximum allowable power P of the DC test device in the AC / DC test device. DC_source (t3); when the predicted load P of the equipment under test load (t1) is greater than the maximum allowable power P of the DC type test device in the AC / DC type test device DC_source (t3), that is and If not, return to C7; when the predicted load P of the equipment under test load (t1) is less than or equal to the maximum allowable power P of the DC test device in the AC / DC test device. DC_source (t3), that is and If true, return to C1; C5. Send the test normal completion information to the parallel power electronic equipment test system, send a shutdown command to the equipment under test, and after the equipment under test is shut down, send a shutdown command to the AC / DC test device. C6. Send fault warning information of the AC test device to the parallel power electronic equipment test system, send a shutdown command to the device under test, and after the device under test is shut down, send a shutdown command to the AC / DC test device; C7. Send fault warning information of the DC test device to the parallel power electronic equipment test system, send a shutdown command to the equipment under test, and after the equipment under test is shut down, send a shutdown command to the AC and DC test device.

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