A testing method for a large-capacity voltage source converter pair test platform

Abstract

The present invention provides a large-capacity voltage source converter pair test platform and test method, including: a test power supply US, a circuit breaker QF1, a voltage regulator TY, a transformer TF, a circuit breaker QF2 and a test converter TO; the test power supply US, the circuit breaker QF1, the voltage regulator TY, the transformer TF and the circuit breaker QF2 are connected in series in sequence; the output end of the circuit breaker QF2 is connected to the test converter TO; the test converter TO includes N ports of different voltages and power levels. The present invention is realized by changing the control strategy and primary wiring transformation, and no additional test converter device is required; the output voltage of the transformer can be adjusted by the voltage regulator to achieve connection with the grid-connected port of converters of different voltage levels, and the adaptability is strong; it is not limited by the number and capacity of converter ports, and the flexibility is high.

Description

Background Art

[0002] With the continuous advancement of power semiconductor technology, flexible direct current transmission (VSC-HVDC) technology based on voltage source converter has become a new type of power transmission system that has been developed recently. It uses pulse width modulation technology to directly invert DC voltage into AC voltage with controllable amplitude and phase, without the need for phase switching with the receiving grid voltage, and has no restrictions on the system capacity of the receiving grid. It can be used to connect isolated small systems with the main grid. VSC-HVDC can independently and quickly control the transmitted active power and reactive power, thus greatly enhancing the flexibility of power transmission. It can also be used to enhance the voltage stability and damping of AC grids. The technical advantages of VSC-HVDC make it the most promising power transmission method developed recently, especially suitable for stable connection between wind farms and the main grid, power supply to isolated remote small load areas, and capacity expansion and transformation of distribution systems in large and medium-sized cities.

[0003] The core of VSC-HVDC is the voltage source converter based on fully controlled devices. The application of power transmission places extremely high demands on the capacity and voltage level of the voltage source converter. In order to fully verify the performance of large-capacity converters, it is necessary to conduct full-power tests on them during factory tests to fully assess the reliability of the designs of power devices, cooling systems, and current-passing components.

[0004] At present, there are generally two methods for full-power testing, direct testing and back-to-back drag testing. The direct testing method has high requirements on the power supply and equipment capacity of the laboratory, and with the continuous increase in the capacity of the converter, it is difficult to achieve in laboratory conditions; the back-to-back drag testing method has lower requirements on the power supply capacity, but it is necessary to build a set of voltage source converters of the same capacity level as a testing device, which has a high cost and occupies a large area. Summary of the invention

[0005] The invention provides a large-capacity voltage source converter pair-drag test platform which has high economy, small footprint and strong feasibility.

[0006] The towing test platform includes: test power supply US, circuit breaker QF1, voltage regulator TY, transformer TF, circuit breaker QF2 and test product converter TO;

[0007] The test power supply US, circuit breaker QF1, voltage regulator TY, transformer TF and circuit breaker QF2 are connected in series in sequence;

[0008] The output end of the circuit breaker QF2 is connected to the test transformer TO;

[0009] The test converter TO includes N ports with different voltage and power levels.

[0010] It should be further explained that each power port is split into two sub-ports with the same current level and voltage reduction or the same voltage level and current reduction and having a preset capacity.

[0011] It should be further explained that the output of the voltage regulator TY is adjusted so that the output voltage of the transformer TF is half of the rated voltage of the grid-connected port.

[0012] It should be further explained that the converter connected to the output end of the circuit breaker QF2 is provided with a high voltage sub-port H1;

[0013] The high voltage sub-port H1 is composed of modules HA1 to HAM / 2.

[0014] The converter connected to the output end of the circuit breaker QF2 is also provided with a high-voltage sub-port H2;

[0015] The high-voltage sub-port 2 H2 is composed of modules HV(M / 2+1) to HVM.

[0016] The converter connected to the output end of the circuit breaker QF2 is also provided with a low voltage sub-port L1;

[0017] The low voltage sub-port L1 is composed of modules LD1 to LDN / 2.

[0018] The converter connected to the output end of the circuit breaker QF2 is also provided with a low voltage sub-port 2 L2;

[0019] The low voltage sub-port 2 L2 is composed of modules LD(N / 2+1)~LDN.

[0020] It should be further explained that the test power supply US, the circuit breaker QF1, the voltage regulator TY, the transformer TF, the circuit breaker QF2 and the test product converter TO are three-phase circuits respectively.

[0021] The present invention also provides a large-capacity voltage source converter pair-drag test method, the method comprising:

[0022] During the test, the circuit breaker QF1 is closed and the output voltage of the voltage regulator TY is adjusted to make the output voltage of the transformer TF consistent with the voltage amplitude of the two sub-ports;

[0023] Close the circuit breaker QF2, and the test power supply is boosted by the transformer TF to supply power to the two high-voltage sub-ports, and all H-bridge 1 modules of the two high-voltage sub-port modules are unlocked in turn to complete the grid connection;

[0024] Unlock all H-bridge 2 modules of the two high-voltage sub-ports respectively, rectify and charge the supporting capacitor through the high-frequency transformer and the diode of the H-bridge 3 module in the low-voltage sub-port module, so that all modules in the low-voltage sub-port can work with power;

[0025] Unlock all H-bridge 3 modules in the low voltage sub-port 1, and control the voltage of the H-bridge 3 modules to a preset value in the voltage control mode;

[0026] The low-voltage sub-port 2 collects the output voltage of the sub-port 1, and then unlocks the H-bridge 3 module. In the power control mode, the power flow direction and size are controlled through the sub-port 1 to control the power within the rated power, thereby realizing the double-drag of the entire converter equipment.

[0027] It can be seen from the above technical solutions that the present invention has the following advantages:

[0028] The voltage source large-capacity converter pair-drag test platform provided by the present invention only needs to supplement the energy consumed by the equipment pair-drag, has low capacity requirements for test equipment such as test power supplies and test transformers, and has strong real-time performance.

[0029] The voltage source large-capacity converter pair test platform can adjust the output voltage of the transformer through the voltage regulator to achieve connection with the grid-connected ports of converters of different voltage levels, with strong adaptability. It is also not limited by the number and capacity of converter ports and has high flexibility.

[0030] During the towing test, the output of the voltage regulator is first adjusted to make the output voltage of the transformer half of the rated voltage of the grid-connected port, and then the grid-connected port is controlled to operate in a following mode, and half of the remaining ports operate in a voltage control mode and half operate in a power control mode. The power control value is half of the rated power of the corresponding port. On this basis, full-power towing of the entire large-capacity converter device is achieved, thereby achieving the purpose of fully evaluating the high-power operating performance of power devices, heat dissipation systems and current-passing components. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings required for use in the description will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0032] Figure 1 This is a schematic diagram of a large-capacity voltage source converter pair test platform;

[0033] Figure 2 This is a connection diagram of the converter and the towing test platform;

[0034] Figure 3 This is a topological diagram of the port module of the converter device. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The units and algorithm steps of each example described in the embodiments disclosed in the large-capacity voltage source converter tow test platform and test method provided by the present invention can be implemented by electronic hardware, computer software or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0037] The block diagrams shown in the drawings of the large-capacity voltage source converter pair-drag test platform and the test method provided by the present invention are only functional entities, and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0038] In the large-capacity voltage source converter tow test platform and test method provided by the present invention, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiment described above is only schematic. For example, the division of the unit is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or it can be an electrical, mechanical or other form of connection.

[0039] In addition, the features, structures or characteristics described in the large-capacity voltage source converter tow test platform and test method provided by the present invention can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to give a full understanding of the embodiments of the present invention. However, those skilled in the art will appreciate that the technical solution of the present invention can be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, well-known methods, devices, implementations or operations are not shown or described in detail to avoid blurring various aspects of the present invention.

[0040] like Figures 1 to 3 As shown, the large-capacity voltage source converter pair-drag test platform provided by the present invention includes: a test power supply US, a circuit breaker QF1, a voltage regulator TY, a transformer TF, a circuit breaker QF2 and a test converter TO; the test power supply US, the circuit breaker QF1, the voltage regulator TY, the transformer TF and the circuit breaker QF2 are connected in series in sequence; the output end of the circuit breaker QF2 is connected to the test converter TO; the test converter TO includes N ports with different voltages and power levels.

[0041] The present invention is to split each power port into two sub-ports with the same current level and voltage reduction or the same voltage level and current reduction, and with preset capacity. That is, sub-ports A1, B1~N1 constitute converter 1, and sub-ports A2, B2~N2 constitute converter 2. During the towing test, the grid-connected ports, that is, ports A1 and A2, operate in the follow-up mode, B1~N1 operate in the voltage control mode, and B2~N2 operate in the power control mode. The output of the voltage regulator is adjusted so that the output voltage of the transformer is half of the rated voltage of the grid-connected port. On this basis, the full power towing of the entire large-capacity converter device is achieved, and the high-power operation performance of the power devices and the current-passing components is fully evaluated.

[0042] The voltage source large-capacity converter pair-drag test platform provided by the present invention only needs to supplement the energy consumed by the equipment pair-drag, has low capacity requirements for test equipment such as test power supplies and test transformers, and has strong real-time performance.

[0043] The voltage source large-capacity converter pair test platform can adjust the output voltage of the transformer through the voltage regulator to achieve connection with the grid-connected ports of converters of different voltage levels, with strong adaptability. It is also not limited by the number and capacity of converter ports and has high flexibility.

[0044] Furthermore, during the towing test, the output of the voltage regulator is first adjusted so that the output voltage of the transformer is half of the rated voltage of the grid-connected port, and then the grid-connected port is controlled to operate in the following mode. Half of the remaining ports operate in the voltage control mode and half operate in the power control mode. The power control value is half of the rated power of the corresponding port. On this basis, the full-power towing of the entire large-capacity converter device is achieved, thereby achieving the purpose of fully assessing the high-power operation performance of power devices, heat dissipation systems and current-passing components.

[0045] Based on the above large-capacity voltage source converter pair-drag test platform, the present invention also provides a large-capacity voltage source converter pair-drag test method, in which:

[0046] Before the test, the high-voltage AC port was configured as two sub-ports with the same current level but half the voltage level. The sub-port one H1 was composed of modules HA1~HAM / 2, and the sub-port two H2 was composed of modules HV(M / 2+1)~HVM; then the low-voltage DC port was configured as two sub-ports with the same voltage level but half the current level. The sub-port one L1 was composed of modules LD1~LDN / 2, and the sub-port two L2 was composed of modules LD(N / 2+1)~LDN.

[0047] During the test, the circuit breaker QF1 is closed and the output voltage of the voltage regulator TY is adjusted to make the output voltage of the transformer TF consistent with the voltage amplitude of the two high-voltage AC sub-ports;

[0048] Close the circuit breaker QF2, and the test power supply is boosted by the transformer to supply power to the two high-voltage sub-ports, and all H-bridge 1 modules of the two sub-port modules are unlocked in turn to complete the grid connection;

[0049] Unlock the H-bridge 2 modules of the two high-voltage sub-ports respectively, and rectify and charge the supporting capacitor through the high-frequency transformer and the H-bridge 3 module diode in the low-voltage sub-port, so that all modules in the low-voltage sub-port are powered and work;

[0050] In the low voltage sub-port 1, the H-bridge 3 module is unlocked and operated in the voltage control mode to control the module voltage at the required value;

[0051] The low-voltage sub-port 2 collects the output voltage of the sub-port 1, then unlocks all H-bridge 3 modules and runs in the power control mode. By controlling the direction and size of the port power flow, the power is controlled at the rated power, thereby realizing the double-drag of the entire converter equipment.

[0052] The large-capacity voltage source converter pair-drag test platform and test method provided by the present invention are units and algorithm steps of each example described in combination with the embodiments disclosed herein, and can be implemented by electronic hardware, computer software or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0053] Those skilled in the art will appreciate that the various aspects of the large-capacity voltage source converter pair-drag test platform and test method provided by the present invention can be implemented as a system, method or program product. Therefore, various aspects of the present disclosure can be specifically implemented in the following forms, namely: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or an implementation combining hardware and software, which can be collectively referred to as a "circuit", "module" or "system" here.

[0054] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A large-capacity voltage source converter pair-drag test method, characterized in that: Methods A large-capacity voltage source converter pair-drag test platform was used; The large-capacity voltage source converter pair test platform includes: a test power supply US, a circuit breaker QF1, a voltage regulator TY, a transformer TF, a circuit breaker QF2 and a test converter TO; the test power supply US, the circuit breaker QF1, the voltage regulator TY, the transformer TF and the circuit breaker QF2 are connected in series in sequence; the output end of the circuit breaker QF2 is connected to the test converter TO; the test converter TO includes N ports with different voltages and power levels; Methods include: During the test, the circuit breaker QF1 is closed and the output voltage of the voltage regulator TY is adjusted to make the output voltage of the transformer TF consistent with the voltage amplitude of the two sub-ports; Close the circuit breaker QF2, and the test power supply is boosted by the transformer TF to supply power to the two high-voltage sub-ports, and all H-bridge 1 modules of the two high-voltage sub-port modules are unlocked in turn to complete the grid connection; Unlock all H-bridge 2 modules of the two high-voltage sub-ports respectively, rectify and charge the supporting capacitor through the high-frequency transformer and the diode of the H-bridge 3 module in the low-voltage sub-port module, so that all modules in the low-voltage sub-port can work with power; Unlock all H-bridge 3 modules in the low voltage sub-port 1, and control the voltage of the H-bridge 3 modules to a preset value in the voltage control mode; The low-voltage sub-port 2 collects the output voltage of the sub-port 1, and then unlocks the H-bridge 3 module. In the power control mode, the power flow direction and size are controlled through the sub-port 1 to control the power within the rated power, thereby realizing the double-drag of the entire converter equipment.

2. The large-capacity voltage source converter pair-drag test method according to claim 1, characterized in that: Each power port is split into two sub-ports with the same current level and voltage reduction or the same voltage level and current reduction, and have preset capacities.

3. The large-capacity voltage source converter pair-drag test method according to claim 2, characterized in that: Adjust the output of the voltage regulator TY so that the output voltage of the transformer TF is half of the rated voltage of the grid-connected port.

4. The large-capacity voltage source converter pair-drag test method according to claim 1, characterized in that: The converter connected to the output end of the circuit breaker QF2 is provided with a high voltage sub-port H1; The high voltage sub-port H1 is composed of modules HA1 to HAM / 2.

5. The large-capacity voltage source converter pair-drag test method according to claim 4, characterized in that: The converter connected to the output end of the circuit breaker QF2 is also provided with a high-voltage sub-port H2; The high-voltage sub-port 2 H2 is composed of modules HV(M / 2+1) to HVM.

6. The large-capacity voltage source converter pair-drag test method according to claim 1, characterized in that: The converter connected to the output end of the circuit breaker QF2 is also provided with a low voltage sub-port L1; The low voltage sub-port L1 is composed of modules LD1 to LDN / 2.

7. The large-capacity voltage source converter pair-drag test method according to claim 6, characterized in that: The converter connected to the output end of the circuit breaker QF2 is also provided with a low voltage sub-port 2 L2; The low voltage sub-port 2 L2 is composed of modules LD(N / 2+1)~LDN.

8. The large-capacity voltage source converter pair-drag test method according to claim 1, characterized in that: The test power supply US, circuit breaker QF1, voltage regulator TY, transformer TF, circuit breaker QF2 and test product converter TO are three-phase circuits respectively.

Images