A low power supply capacity, wide adaptation type three-winding energy closed-loop power cycle test platform

Abstract

The application discloses a low power distribution capacity, wide adaptation type three-winding energy closed-loop power cycle test platform, and belongs to the technical field of power electronic equipment testing, which comprises a three-winding transformer having a primary winding and two independent secondary windings; a rectifying device is connected between the first secondary winding and a first DC bus, an inverting device is connected between the second secondary winding and a second DC bus, a DC-DC conversion device is connected between the two DC buses; the platform further comprises three sets of layered control systems which independently control the rectifying device, the inverting device and the DC-DC conversion device, so that the rectifying device transmits active power from the first secondary winding to the first DC bus, the inverting device feeds back active power from the second DC bus to the second secondary winding, and the magnetic motive forces of the two sets of secondary windings are mutually offset in the iron core. The application greatly reduces the power distribution capacity, realizes decoupling and independent voltage regulation of the rectifying side and the inverting side, and is compatible with test of arbitrary ratio DC-DC devices.

Description

Technical Field

[0001] This invention belongs to the field of power electronic equipment testing technology, and in particular relates to a low power distribution capacity, wide adaptability three-winding energy closed-loop power cycle testing platform. Background Technology

[0002] Currently, the mainstream testing schemes for the factory delivery and type testing of high-power power electronic converter equipment (such as rectifiers, inverters, DC-DC converters, energy storage PCS, and vehicle-mounted high-voltage modules) mainly include pure resistive load energy consumption testing, dual-machine feedback schemes, and single-winding transformer feedback schemes. Among these, the pure resistive load energy consumption test uses full-power grid power supply and dissipates all test power as heat. Its system structure is simple, easy to control, and can stably complete temperature rise and aging tests at rated power. The dual-machine feedback scheme connects two identical converters on their DC sides and their AC sides to the grid, allowing some power to circulate and be fed back between the two machines. Compared to pure resistive loads, this can reduce distribution capacity by approximately 20% to 30%, thus reducing grid supply pressure and operating energy consumption to some extent. The single-winding transformer feedback scheme uses a single secondary winding to achieve energy feedback, enabling basic power cycle testing and providing some energy-saving effects. All of these schemes have played a positive role in specific application scenarios, providing fundamental testing methods for the reliability verification of power electronic equipment.

[0003] However, the aforementioned existing technologies still have significant shortcomings. First, the power distribution capacity for purely resistive load energy consumption testing must equal the test capacity, requiring the power grid to supply power at 100% full power, resulting in extremely high electricity costs and enormous energy consumption. Second, while the dual-machine feedback scheme can partially reduce the power distribution capacity, the degree of power offsetting is limited, and the power grid still needs to bear 20% to 30% of the test capacity, placing high demands on the capacity of distribution transformers, buses, and switchgear, and failing to achieve deep power offsetting. Third, the topology of the single-winding transformer feedback scheme is fixed, with deep coupling between the rectifier and inverter sides, making it impossible to independently establish DC buses of different voltage levels, and difficult to adapt to the testing needs of DC-DC bidirectional equipment with different turns ratios and voltage levels. In addition, existing platforms generally suffer from poor versatility, insufficient control stability, and weak dynamic disturbance rejection capabilities. When the voltage or power level of the device under test changes, it often requires overall hardware modification, and it is difficult to achieve long-term, continuous, and stable operation at 100% rated power with extremely low power distribution capacity. Therefore, how to further reduce the power distribution capacity of high-power test platforms, improve energy feedback efficiency, enhance the platform's adaptability to DC-DC devices with different voltage levels and transformation ratios, and achieve decoupled and stable operation among multiple control targets has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a low-capacity, wide-adaptability three-winding energy closed-loop power cycle test platform to solve the problems existing in the prior art.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a low-capacity, wide-adaptability three-winding energy closed-loop power cycle test platform, comprising a three-winding transformer, a rectifier, an inverter, and a DC-DC converter, characterized in that: The three-winding transformer has one primary winding and two independent secondary windings that are magnetically coupled to each other, and the primary winding and secondary winding are configured with asymmetrical capacity. The rectifier is connected between the first secondary winding and the first DC bus, the inverter is connected between the second secondary winding and the second DC bus, and the DC-DC converter is connected across the first DC bus and the second DC bus. The platform also includes three hierarchical control systems, which independently manage the rectifier, the inverter, and the DC-DC converter. The three hierarchical control systems are configured to enable the rectifier to transmit active power from the first secondary winding to the first DC bus, enable the inverter to feed back active power from the second DC bus to the second secondary winding, and enable the magnetomotive forces generated by the two secondary windings to cancel each other out in the iron core. The primary side of the power grid only needs to supplement the system losses to maintain the power closed-loop cycle.

[0006] Preferably, the rated capacity of the primary winding of the three-winding transformer is configured to match only the total system loss, and the rated capacity of both sets of secondary windings matches the rated test capacity of the rectifier, inverter and DC-DC converter.

[0007] Preferably, the first secondary winding is connected to the AC input terminal of the rectifier via a first switch and a filter unit, and the second secondary winding is connected to the AC output terminal of the inverter via a second switch and a filter unit.

[0008] Preferably, the three hierarchical control systems are a first control system for controlling the rectifier, a second control system for controlling the inverter, and a third control system for controlling the DC-DC converter, with the first control system and the second control system being completely decoupled.

[0009] Preferably, the first control system independently controls the rectifier to establish a first DC bus voltage with continuously adjustable amplitude, and the second control system independently controls the inverter to establish a second DC bus voltage with a different level from the first DC bus voltage. The two DC bus voltages are independent of each other and are not bound to each other.

[0010] Preferably, the first control system and the second control system achieve deep cancellation of magnetomotive force in the iron core by means of coordinated active closed-loop control, so that the active power amplitudes of the two sets of secondary windings are matched.

[0011] Preferably, under the independent adjustment of the third control system, the DC-DC converter can achieve stepless loading test within the rated power range under any voltage difference and any turns ratio.

[0012] Preferably, the platform does not require the configuration of a large-capacity resistive load, and when the platform is expanded, only the secondary converter module needs to be upgraded without expanding the front-end power distribution system.

[0013] Preferably, the three hierarchical control systems operate independently, respectively realizing voltage and power closed loops on the rectifier side, voltage and power closed loops on the inverter side, and power and current closed loops on the DC-DC converter side.

[0014] Secondly, the present invention also provides a deep cancellation power cycle decoupling control method based on the low power distribution capacity, wide adaptability three-winding energy closed-loop power cycle test platform described in the first aspect, comprising the following steps: The three hierarchical control systems perform self-tests upon power-up and complete DC bus pre-charging. The first control system controls the rectifier to establish and stabilize the first DC bus voltage; The second control system controls the inverter to establish the second DC bus voltage and feeds energy back to the second secondary winding; Real-time adjustment of the current in the two sets of secondary windings causes the magnetomotive forces to cancel each other out. The third control system controls the DC-DC converter to adjust the transmission power to a preset value; Real-time monitoring of the input power of the primary power grid and automatic compensation for system losses.

[0015] Compared with the prior art, the present invention has the following advantages and technical effects: This invention employs a three-winding transformer with one primary winding and two independent secondary windings, with an asymmetrical capacity configuration between the primary and secondary windings. Combined with a three-tiered control system configured to allow the rectifier to transmit active power from the first secondary winding to the first DC bus, and the inverter to feed back active power from the second DC bus to the second secondary winding, the magnetomotive forces generated by the two secondary windings cancel each other out within the core. The primary side of the power grid only needs to compensate for system losses to maintain a closed-loop power supply. This scheme changes the traditional testing platform model where the entire test power is supplied by the power grid, significantly reducing the installed capacity of the distribution system to only match system losses.

[0016] This invention employs three hierarchical control systems to independently manage the rectifier, inverter, and DC-DC converter, ensuring that each device is independently controlled. The rectifier can independently establish a first DC bus voltage, and the inverter can independently establish a second DC bus voltage; the two DC bus voltages are independent of each other. This configuration solves the technical problem of the inability to differentiate voltage regulation due to strong coupling between the rectifier and inverter sides.

[0017] This invention connects a rectifier between the first secondary winding and the first DC bus, an inverter between the second secondary winding and the second DC bus, and a DC-DC converter between the first DC bus and the second DC bus. By combining two independently adjustable DC bus voltages, the DC-DC converter can achieve flexible loading tests across the entire power range under any voltage difference and any turns ratio.

[0018] This invention enables the rectifier to transmit active power and the inverter to feed back active power through the coordinated configuration of three hierarchical control systems. The magnetomotive force generated by the two sets of secondary windings cancels each other out in the iron core. The main test power forms a closed loop inside the three-winding transformer. The primary side of the power grid only needs to provide the active power required for the total system loss. The energy feedback efficiency is significantly improved, and the energy consumption of the test operation is greatly reduced.

[0019] Through the aforementioned magnetomotive force deep cancellation and power closed-loop circulation mechanism, the main power does not depend on resistive load dissipation. The test platform can maintain continuous cyclic operation at 100% rated power under conditions without large-capacity resistive load, avoiding high-power heat generation and heat dissipation problems, and improving the long-term operational stability and reliability of the test platform. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the overall topology and energy closed-loop path of an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the principle of deep cancellation of the magnetomotive force of a three-winding transformer according to an embodiment of the present invention. Figure 3 This is a diagram showing the magnetomotive force vector relationship of a three-winding transformer according to an embodiment of the present invention. Figure 4 This is a diagram of a three-layer hierarchical decoupling control method according to an embodiment of the present invention; Figure 5 This is a flowchart of the control method according to an embodiment of the present invention. Detailed Implementation

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0023] Example 1 This embodiment provides a low power distribution capacity, wide adaptability three-winding energy closed-loop power cycle test platform, including a three-winding transformer, a rectifier, an inverter, and a DC-DC converter. The three-winding transformer has one primary winding and two independent secondary windings that are magnetically coupled to each other, and the primary winding and secondary winding are configured with asymmetrical capacity. Furthermore, the rated capacity of the primary winding of the three-winding transformer is configured to match only the total system loss, while the rated capacity of both secondary windings matches the rated test capacity of the rectifier, inverter, and DC-DC converter.

[0024] Specifically, the three-winding transformer adopts an asymmetric differentiated capacity design. The rated capacity of the primary winding only matches the total loss power of the entire closed-loop system, accounting for 5% to 6% of the full-load test capacity of the device under test. The rated capacity of the two independent secondary windings matches the rated test capacity of the rectifier, inverter and DC-DC device, so that only 6% of the power distribution capacity can complete the 100% test capacity high-power test.

[0025] In this embodiment, the primary winding of the three-winding transformer has N1 turns, the first secondary winding has N2 turns, and the second secondary winding has N3 turns. The control system adjusts the magnetomotive force F2 = N2·I2 of the first secondary winding to be approximately equal in magnitude and opposite in direction to the magnetomotive force F3 = N3·I3 of the second secondary winding, achieving deep cancellation within the core and satisfying the vector equation. . Figure 2 This is a schematic diagram illustrating the principle of deep cancellation of magnetomotive force in a three-winding transformer. Figure 3 This is a diagram showing the magnetomotive force vector relationship of a three-winding transformer.

[0026] The three-winding transformer in this embodiment can rationally configure the primary and secondary winding capacities according to the actual rated power and losses of the equipment, thereby maximizing cost savings. It also meets the equipment's rated power testing requirements.

[0027] The rectifier is connected between the first secondary winding and the first DC bus, the inverter is connected between the second secondary winding and the second DC bus, and the DC-DC converter is connected across the first DC bus and the second DC bus. Furthermore, the first secondary winding is connected to the AC input terminal of the rectifier via a first switch and a filter unit, and the second secondary winding is connected to the AC output terminal of the inverter via a second switch and a filter unit.

[0028] Specifically, the first secondary winding is connected to the AC input terminal of the rectifier via a switch and a filter; the second secondary winding is connected to the AC output terminal of the inverter via a switch and a filter.

[0029] The rectifier absorbs active power from the secondary side of the transformer and pumps the energy into the DC voltage loop, allowing arbitrary control of the voltage amplitude of the first DC bus.

[0030] The rectifier in this embodiment can be any topology, such as two-level, three-level, isolated, or non-isolated. It can also simulate the real-time power change scenario of wind power generation devices or photovoltaic power generation equipment, and change the output power in real time.

[0031] The inverter absorbs energy from the DC link and actively and precisely feeds it back to the other secondary winding of the transformer, and arbitrarily controls the voltage amplitude of the second DC bus.

[0032] The inverter device in this embodiment can be any topology, including two-level, three-level, isolated, or non-isolated types. It can also simulate the working scenario of a wind power converter or a photovoltaic inverter grid-connected device, and follow the input power in real time. Furthermore, under the independent adjustment of the third control system, the DC-DC converter can achieve stepless loading tests within the rated power range under arbitrary voltage difference and arbitrary turns ratio conditions.

[0033] Specifically, the DC-DC converter is connected between two independent DC buses with different voltage levels. The third control system independently adjusts the output current, power flow direction and transmission power of the DC-DC converter, and can achieve stepless loading test of 0~100% rated power under any voltage difference and any transformation ratio.

[0034] The DC-DC converter in this embodiment can be any DC-DC converter topology, including boost, buck, isolated, or non-isolated converters.

[0035] like Figure 1As shown, the rectifier stabilizes the voltage of the first DC bus and simultaneously absorbs power from the N2 winding of the transformer in real time to meet the power requirements of the DC-DC converter. The inverter stabilizes the voltage of the second DC bus and simultaneously feeds the power output from the DC-DC converter back to the N3 winding of the transformer in real time. The DC-DC converter is connected between the first and second DC buses and adjusts the power and current of the DC-DC converter according to actual commands to achieve various operating conditions. The N2 and N3 windings of the three-winding transformer, one outputting energy and the other feeding energy, achieve mutual cancellation of magnetomotive forces, and the primary winding N1 of the transformer only needs to provide system losses.

[0036] The platform also includes three hierarchical control systems, which independently manage the rectifier, the inverter, and the DC-DC converter. The three hierarchical control systems are configured to enable the rectifier to transmit active power from the first secondary winding to the first DC bus, enable the inverter to feed back active power from the second DC bus to the second secondary winding, and enable the magnetomotive forces generated by the two secondary windings to cancel each other out in the iron core. The primary side of the power grid only needs to supplement the system losses to maintain the power closed-loop cycle.

[0037] Furthermore, the three hierarchical control systems are respectively a first control system for controlling the rectifier, a second control system for controlling the inverter, and a third control system for controlling the DC-DC converter. The first control system is completely decoupled from the second control system.

[0038] Furthermore, the first control system independently controls the rectifier to establish a first DC bus voltage with continuously adjustable amplitude, and the second control system independently controls the inverter to establish a second DC bus voltage with a different level from the first DC bus voltage. The two DC bus voltages are independent of each other and are not bound to each other.

[0039] Furthermore, the first control system and the second control system achieve deep cancellation of magnetomotive force in the iron core by coordinating active closed-loop control to match the active power amplitude of the two sets of secondary windings.

[0040] Furthermore, the three hierarchical control systems operate independently, respectively realizing voltage and power closed loops on the rectifier side, voltage and power closed loops on the inverter side, and power and current closed loops on the DC-DC converter side.

[0041] Specifically, the first control system and the second control system are completely decoupled. The first control system independently controls the rectifier side to establish a first DC bus voltage with continuously adjustable amplitude; the second control system independently controls the inverter side to independently establish a second DC bus voltage with different amplitude. The two DC bus voltage levels are independent of each other and are not bound to each other.

[0042] This embodiment uses the first control system and the second control system to coordinate active closed-loop control, accurately matching the active power amplitude of the two sets of secondary windings, so that the magnetomotive forces of the two sets of secondary windings in the transformer core are deeply canceled, and the primary winding only needs to provide loss active power, which greatly reduces the power throughput demand of the grid side.

[0043] During operation, the first control system controls the rectifier to transmit active power from the first secondary winding to the DC loop; the second control system controls the inverter to feed back active power from the DC loop into the second secondary winding; the alternating magnetomotive force generated by the two secondary windings cancels each other out in the core of the three-winding transformer, and the primary side of the power grid only needs to replenish all the active power loss of the system to maintain the continuous cyclic operation of 100% rated test power in the DC loop.

[0044] Furthermore, the platform does not require the configuration of large-capacity resistive loads, and when the platform is expanded, only the secondary converter module needs to be upgraded without expanding the front-end power distribution system.

[0045] Specifically, the entire platform can conduct long-term temperature rise tests, continuous aging durability tests, efficiency tests, overload capacity tests, and dynamic power cycle tests on high-power converter equipment without requiring large-capacity resistive loads or full power support from the power grid.

[0046] This embodiment breaks away from the industry's conventional design thinking that "the larger the test, the larger the power distribution capacity." It only requires 6% of the power distribution installed capacity to stably support 100% rated power full-load power cycle testing, reducing power distribution investment by more than 90%.

[0047] This embodiment uses a control system to precisely regulate the active power amplitude and phase on both sides, so that the magnetomotive forces generated by the two sets of secondary sides are approximately equal in magnitude and basically opposite in direction, achieving near-complete cancellation inside the transformer core. Ultimately, the primary side of the power grid only needs to supplement a small amount of active power such as the overall system loss, transformer copper loss, and transformer iron loss, without having to bear the main cycle power of the test.

[0048] The beneficial effects of this embodiment: In this embodiment, the installed capacity on the distribution side is reduced to less than 6% of that of the traditional scheme, and the one-time investment in civil engineering, transformers, switchgear, and busbars of the test station is reduced by more than 90%; the energy saving rate during long-term full-power test operation exceeds 90%. This embodiment achieves deep cancellation of magnetomotive force, with the main power circulating inside the transformer. The power grid only compensates for losses, eliminating high-power ineffective heat generation and waste, making it green and low-carbon. The three-layer decoupling control in this embodiment avoids multi-loop coupling oscillation, and its voltage fluctuation suppression capability and load sudden change recovery time are far superior to existing solutions, supporting 7×24-hour uninterrupted full-power aging durability tests; The two independent adjustable DC buses in this embodiment can flexibly set any voltage difference, perfectly matching the research and development verification, factory sampling inspection and certification test of DC-DC products with any transformation ratio and any power level; This embodiment can complete all national / industry standard type test items, including steady-state efficiency test, temperature rise test, overload capacity test, dynamic load step test, high and low voltage ride-through test, and long-term power cycle fatigue test. In this embodiment, subsequent upgrades to the test power level only require upgrading the secondary converter module, without the need for significant expansion of the front-end power grid distribution, thus greatly improving the platform's lifespan and scalability.

[0049] Example 2 Based on the same inventive concept, this embodiment provides a deep cancellation power cycle decoupling control method based on the low power distribution capacity, wide adaptability three-winding energy closed-loop power cycle test platform described in Embodiment 1, including the following steps: Step 1: The three sets of hierarchical control systems are powered on, perform self-tests, and complete the pre-charging of the DC bus; Step 2: The first control system controls the rectifier to establish and stabilize the first DC bus voltage; Step 3: The second control system controls the inverter to establish the second DC bus voltage and feeds energy back to the second secondary winding; Step 4: Adjust the current in the two sets of secondary windings in real time to make the magnetomotive forces cancel each other out. Specifically, the rectifier-side current I2 and the inverter-side current I3 are dynamically adjusted in real time to ensure that the two sets of secondary magnetomotive forces F2=N2・I2 and F3=N3・I3 of the three-winding transformer are deeply canceled out, satisfying the requirements of the real-time dynamic control. .

[0050] Step 5: The third control system controls the DC-DC converter to adjust the transmission power to a preset value; Specifically, the third control system controls the DC-DC device to adjust the bidirectional transmission power according to the test procedure, and accurately loads it to the preset test power point.

[0051] Step 6: Monitor the input power of the primary grid in real time and automatically compensate for system losses.

[0052] In this embodiment, the input power of the primary grid is monitored in real time throughout the entire process, system losses are automatically compensated, and closed-loop steady-state operation is maintained for a long period of time. Specifically, this embodiment proposes a three-layer decoupling and cooperative control strategy, such as... Figure 4As shown, it includes: voltage and power closed-loop of the rectifier, voltage and power closed-loop of the inverter, and power and current closed-loop of the DC-DC converter. The voltage and power closed-loop of the rectifier is used to stabilize the first DC bus voltage and simultaneously absorb power from the N2 winding of the transformer to the DC-DC converter in real time, meeting the power requirements of the DC-DC converter. The voltage and power closed-loop of the inverter is used to stabilize the second DC bus voltage and simultaneously feed power back from the DC-DC converter to the N3 winding of the transformer in real time. The power and current closed-loop of the DC-DC converter is used to output the set power and current according to the command.

[0053] like Figure 5 As shown, the specific control method is as follows: First, the voltage and current information of the two secondary windings of the transformer, the voltage information of the first and second DC buses, and the power command information are acquired. Second, using the acquired voltage and current information of the transformer secondary winding 1, the rectifier completes voltage, active power, and reactive power dual closed-loop control to achieve stable first DC bus voltage and real-time power follow-up output. Next, using the acquired voltage and current information of the transformer secondary winding 2, the inverter completes voltage, active power, and reactive power dual closed-loop control to achieve stable second DC bus voltage and real-time power feedback. Finally, using the acquired voltage and power commands, the DC-DC converter achieves power, voltage, and current dual closed-loop control.

[0054] Through the above control steps, the magnetomotive forces on the secondary side of the transformer can be mutually canceled out, and the magnetomotive force F0 of the N1 winding on the primary side of the transformer only needs to maintain the losses of the entire system.

[0055] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A low-capacity, wide-adaptability three-winding energy closed-loop power cycle test platform, characterized in that, It includes a three-winding transformer, a rectifier, an inverter, and a DC-DC converter, characterized in that: The three-winding transformer has one primary winding and two independent secondary windings that are magnetically coupled to each other, and the primary winding and secondary winding are configured with asymmetrical capacity. The rectifier is connected between the first secondary winding and the first DC bus, the inverter is connected between the second secondary winding and the second DC bus, and the DC-DC converter is connected across the first DC bus and the second DC bus. The platform also includes three hierarchical control systems, which independently manage the rectifier, the inverter, and the DC-DC converter. The three hierarchical control systems are configured to enable the rectifier to transmit active power from the first secondary winding to the first DC bus, enable the inverter to feed back active power from the second DC bus to the second secondary winding, and enable the magnetomotive forces generated by the two secondary windings to cancel each other out in the iron core. The primary side of the power grid only needs to supplement the system losses to maintain the power closed-loop cycle.

2. The power cycling test platform according to claim 1, characterized in that, The rated capacity of the primary winding of the three-winding transformer is configured to match only the total system loss, while the rated capacity of both secondary windings matches the rated test capacity of the rectifier, inverter, and DC-DC converter.

3. The power cycling test platform according to claim 1, characterized in that, The first secondary winding is connected to the AC input terminal of the rectifier via a first switch and a filter unit, and the second secondary winding is connected to the AC output terminal of the inverter via a second switch and a filter unit.

4. The power cycling test platform according to claim 1, characterized in that, The three hierarchical control systems are a first control system for controlling the rectifier, a second control system for controlling the inverter, and a third control system for controlling the DC-DC converter. The first control system is completely decoupled from the second control system.

5. The power cycling test platform according to claim 4, characterized in that, The first control system independently controls the rectifier to establish a first DC bus voltage with continuously adjustable amplitude, and the second control system independently controls the inverter to establish a second DC bus voltage with a different level from the first DC bus voltage. The two DC bus voltages are independent of each other and are not bound to each other.

6. The power cycling test platform according to claim 4, characterized in that, The first control system and the second control system achieve deep cancellation of magnetomotive force in the iron core by coordinating active closed-loop control to match the active power amplitude of the two sets of secondary windings.

7. The power cycling test platform according to claim 1, characterized in that, Under the independent adjustment of the third control system, the DC-DC converter can achieve stepless loading tests within the rated power range under any voltage difference and any turns ratio.

8. The power cycling test platform according to claim 1, characterized in that, The platform does not require the configuration of large-capacity resistive loads, and when the platform is expanded, only the secondary converter module needs to be upgraded without expanding the front-end power distribution system.

9. The power cycling test platform according to claim 1, characterized in that, The three hierarchical control systems operate independently, respectively realizing voltage and power closed loops on the rectifier side, voltage and power closed loops on the inverter side, and power and current closed loops on the DC-DC converter side.

10. A deep cancellation power cycle decoupling control method based on a low power distribution capacity, wide adaptability three-winding energy closed-loop power cycle test platform according to any one of claims 1 to 9, characterized in that, Includes the following steps: The three hierarchical control systems perform self-tests upon power-up and complete DC bus pre-charging. The first control system controls the rectifier to establish and stabilize the first DC bus voltage; The second control system controls the inverter to establish the second DC bus voltage and feeds energy back to the second secondary winding; Real-time adjustment of the current in the two sets of secondary windings causes the magnetomotive forces to cancel each other out. The third control system controls the DC-DC converter to adjust the transmission power to a preset value; Real-time monitoring of the input power of the primary power grid and automatic compensation for system losses.

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