A superconducting synchronous condenser excitation power supply device

Abstract

The application discloses a superconducting synchronous phase modifier excitation power supply device, which comprises a three-phase rectifying device, an adjusting module, a protection module and a digital control module, wherein the three-phase rectifying device is used for providing a bus side DC voltage; the adjusting module is used for adjusting an excitation total current; the protection module is used for ensuring safe operation of the device; and the digital control module is used for realizing high-precision continuous adjustment of excitation winding voltage and current. The superconducting synchronous phase modifier excitation power supply device solves the problem of unbalanced reactive output of the superconducting synchronous phase modifier caused by large excitation current ripple, and improves the reliability of the superconducting synchronous phase modifier.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of excitation power supply of phase modifier, and particularly to a superconducting synchronous phase modifier excitation power supply device. BACKGROUND

[0002] In the current field of reactive power compensation devices in power grid, static reactive power compensator and static synchronous compensator are mainly used, and the new generation of large-capacity phase modifier appears in recent years, and its performance advantage is more obvious than the former two. After the appearance of the new generation of large-capacity phase modifier, other classifications such as superconducting synchronous phase modifier also appear. Before that, the excitation power supply of synchronous motor often uses single power supply to supply power, which determines that if the excitation system is required to provide a higher strong excitation multiple, the control angle of the thyristor rectifier will be in a larger deep control adjustment state when the power supply works in the rated state, so as to have enough strong excitation reserve when working in the strong excitation state. Although this single power supply mode is relatively simple to control, it also brings a series of disadvantages, which not only reduces the power factor of the power supply, but also causes serious distortion of the rectified voltage waveform. With the appearance of superconducting synchronous phase modifier, since the rotor adopts superconducting winding winding and basically presents zero resistance characteristics, the performance requirement of the excitation power supply is higher, and the research and development of a new type of high-low voltage switching excitation power supply is imminent.

[0003] The existing phase modifier excitation power supply system can be roughly divided into DC excitation system, AC excitation system and static excitation system. However, the DC excitation system has a series of problems such as complex start, large overall size, slow dynamic response, and the excitation machine is usually equivalent to a single excitation power supply, which is not suitable for use in superconducting synchronous phase modifier; the AC excitation system has problems such as low reliability, high cost, poor performance and inability to provide negative excitation voltage, and is also not suitable for superconducting phase modifier; the static excitation system is widely used, but has problems such as thyristor control commutation failure, low power factor on the AC side and long response time, and at the same time, since the energy is taken from the generator terminal voltage, it can be equivalent to single power supply, which is also not suitable for superconducting synchronous phase modifier.

[0004] Therefore, in order to improve the reliability of the superconducting synchronous phase modifier and solve the technical problem of unbalanced reactive power output of the superconducting synchronous phase modifier due to large excitation current ripple, it is urgent to build a superconducting synchronous phase modifier excitation power supply device. SUMMARY

[0005] The present application provides a superconducting synchronous phase modifier excitation power supply device, which is used to solve the problem of unbalanced reactive power output of the superconducting synchronous phase modifier due to large excitation current ripple.

[0006] The application provides a superconducting synchronous condenser excitation power supply device, which comprises a three-phase rectifier device, an adjusting module, a protection module and a digital control module connected in sequence.

[0007] The three-phase rectifier device is used for providing a bus side DC voltage.

[0008] The adjusting module is used for adjusting an excitation total current.

[0009] The protection module is used for ensuring safe operation of the device.

[0010] The digital control module is used for realizing high-precision continuous adjustment of excitation winding voltage and current.

[0011] Optionally, the adjusting module comprises a four-phase interleaved parallel buck module and a second-order LC filter module connected with each other.

[0012] The four-phase interleaved parallel buck module is used for reducing excitation current ripple to adjust the excitation total current.

[0013] The second-order LC filter module is used for filtering high-frequency harmonics to ensure high precision of load voltage and current.

[0014] Optionally, the four-phase interleaved parallel buck module is also used for providing low-ripple DC current to the load winding.

[0015] Optionally, the protection module comprises an absorption sub-module.

[0016] The absorption sub-module is used for absorbing energy in the superconducting winding during de-excitation to protect the operation safety of the device.

[0017] Optionally, the digital control module is also used for measuring voltage and current values of excitation electric power.

[0018] Optionally, the digital control module is also used for controlling the four-phase interleaved parallel buck module to send an output signal by detecting load current and voltage values and signal data generated by high-precision digital PI adjustment.

[0019] From the above technical solution, the application has the following advantages:

[0020] The application provides a superconducting synchronous condenser excitation power supply device, which comprises a three-phase rectifier device, an adjusting module, a protection module and a digital control module connected in sequence, the three-phase rectifier device is used for providing a bus side DC voltage, the adjusting module is used for adjusting an excitation total current, the protection module is used for ensuring safe operation of the device, and the digital control module is used for realizing high-precision continuous adjustment of excitation winding voltage and current.

[0021] By the three-phase rectifier device, the adjusting module and the digital control module, high-precision continuous adjustment of the excitation winding voltage and current is realized, by the protection module, safe operation of the device is protected, by the superconducting synchronous phase modifier excitation power supply device, high-precision and high-regulation rate of the excitation current are ensured, the technical problem of unbalanced reactive power output of the superconducting synchronous phase modifier caused by large excitation current ripple is solved, and the reliability of the superconducting synchronous phase modifier is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0023] Figure 1 The structural block diagram of an embodiment of the superconducting synchronous phase modifier excitation power supply device of the present application;

[0024] Figure 2 The structural schematic diagram of the superconducting synchronous phase modifier excitation power supply device of the present application;

[0025] Figure 3 The control block diagram of the superconducting synchronous phase modifier excitation power supply device of the present application;

[0026] Figure 4 The principle diagram of the drive signal of the interleaved parallel buck module and the low-ripple current output in the superconducting synchronous phase modifier excitation power supply device of the present application. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0028] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance.

[0029] Unless otherwise defined, the terms "mounting", "connected", "connecting" are to be construed broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected, can be mechanical connection, can also be electrical connection, can be directly connected, can also be indirectly connected through an intermediate medium, and can be internal communication of two elements.

[0030] Please refer to Figure 1 , Figure 1 It is a structure block diagram of an embodiment of the superconducting synchronous phase modifier excitation power supply device of the application; wherein 101 is a three-phase rectifier device, 102 is a regulation module, 103 is a protection module, and 104 is a digital control module; the three-phase rectifier device 101, the regulation module 102, the protection module 103 and the digital control module 104 are connected in sequence.

[0031] The three-phase rectifier device 101 is used to provide bus side DC voltage.

[0032] The regulation module 102 is used to regulate the total excitation current.

[0033] The protection module 103 is used to ensure the safe operation of the device.

[0034] The digital control module 104 is used to realize high-precision continuous adjustment of the excitation winding voltage and current.

[0035] Please refer to Figure 2 , Figure 2 It is a structure diagram of the superconducting synchronous phase modifier excitation power supply device of the application; wherein 101 is a three-phase rectifier device, 103 is a protection module, and 201 is a four-phase interleaved parallel buck module.

[0036] The superconducting synchronous phase modifier excitation power supply device designed in the application can realize real-time change of excitation current during grid-connected dynamic operation of the superconducting synchronous phase modifier, greatly reduces the ripple of excitation current, and effectively improves the precision of the excitation power supply due to the existence of the control module, so that the system can avoid the problem of unbalanced reactive power output of the superconducting synchronous phase modifier caused by large excitation current ripple, effectively guarantee the precision of the reactive power output of the superconducting synchronous phase modifier, and guarantee the safety of the superconducting winding, greatly improve the reliability of the operation of the superconducting synchronous phase modifier.

[0037] Specifically, the regulation module 102 includes a four-phase interleaved parallel buck module 201 and a second-order LC filter module 202 connected to each other.

[0038] The four-phase interleaved parallel buck module 201 is used to reduce excitation current ripple in order to regulate the total excitation current.

[0039] The second-order LC filter module 202 is used to filter out high-frequency harmonics to ensure high accuracy of load voltage and current.

[0040] Specifically, the four-phase interleaved parallel buck module 201 is also used to provide low-ripple DC current to the load winding.

[0041] Specifically, the value of the total current in the excitation winding is changed by adjusting the duty cycle of the four-phase interleaved parallel buck module 201.

[0042] Specifically, the protection module 103 includes an absorption submodule;

[0043] The absorption submodule is used to absorb energy from the superconducting winding during demagnetization, thereby protecting the operational safety of the device.

[0044] Specifically, the digital control module 104 is also used to measure the voltage and current values ​​of the excitation current.

[0045] Specifically, the digital control module 104 is also used to control the four-phase interleaved parallel buck module 201 to output a signal by detecting the load current value and voltage value, as well as the signal data generated by high-precision digital PI adjustment, so as to realize high-precision continuous adjustment of the excitation winding voltage and current.

[0046] Specifically, please refer to Figure 3 , Figure 3 This is a control block diagram of a superconducting synchronous condenser excitation power supply device according to the present invention; wherein, I ref Here, α is the given value of the excitation current, IL is the conduction angle of the rectifier module, and IL is the given value of the excitation current. i For the phase currents (i = 1, 2, 3, 4) of the four-phase interleaved buck module, I o U is the excitation current. x U is the effective value of the mains voltage, U1 is the DC voltage output by the rectifier module, and U d R0 is the output voltage of the buck module, D is the duty cycle of the PWM signal, R0 is the equivalent resistance of the superconducting excitation winding, and L0 is the equivalent inductance of the superconducting excitation winding.

[0047] The total current of the excitation winding is detected. By comparing the given value with the detected value, the output signal is adjusted by digital PI. The output signal is modulated by a triangular wave to output the PWM control signal of the four-phase buck circuit. The PWM signal output of each phase is shifted by 90° to achieve interleaved control, thereby reducing the output ripple of the total current. The 90° phase shift can be achieved by using an equal amplitude phase shifter.

[0048] The output U1 of the three-phase rectifier device and the grid voltage U x satisfy the following relationship:

[0049] U1=2.34cosαU x ;

[0050] In the formula, U1 is the output voltage of the three-phase rectifier device, U x is the grid voltage. If the duty ratio of the switch tube in the buck module is D, the output voltage U d of the buck module and the output U1 of the rectifier device satisfy the following relationship:

[0051] U d =DU1;

[0052] In the formula, Ud is the output voltage Ud of the buck module; by substituting the formula, the relationship between the output voltage U1 of the excitation power supply and the grid voltage U x can be obtained:

[0053] U d =2.34DcosαU x ;

[0054] The above formula is the relationship between the effective value U1 of the grid voltage and the output voltage U d of the excitation winding. If the resistance of the superconducting excitation winding is equivalent to R0, the actual excitation current is:

[0055]

[0056] In the formula, I o is the excitation current, and R0 is the equivalent resistance of the superconducting excitation winding; in practice, by adjusting the conduction angle α of the rectifier module and the duty ratio D output by the PWM link, the size of the excitation current I o can be roughly determined. Figure 4 It is a schematic diagram of the principle of driving signal and output low-ripple current of the interlaced parallel buck module, and the ripple of two-phase currents with a certain angle can be offset.

[0057] Therefore, in the present application, by adjusting the conduction angle α of the rectifier module and the duty ratio D of the PWM output link, the size of the excitation current can be changed. At the same time, due to the existence of the four-phase interlaced parallel buck module, the ripple of the output excitation current can be greatly reduced. Combined with the high-frequency digital PI control module, high-precision excitation current can be realized, so that the high performance required by the superconducting synchronous condenser excitation power supply can be met.

[0058] The superconducting synchronous condenser excitation power supply device can realize real-time change of excitation current in the process of grid-connected dynamic operation of the superconducting synchronous condenser, greatly reduces the ripple of the excitation current, effectively improves the precision of the excitation power supply through the control module, avoids the imbalance of reactive power output of the superconducting synchronous condenser caused by large excitation current ripple, effectively guarantees the precision of reactive power output of the superconducting synchronous condenser, guarantees the safety of the superconducting winding, and greatly improves the reliability of the operation of the superconducting synchronous condenser.

[0059] The superconducting synchronous condenser excitation power supply device comprises a three-phase rectifier device, a regulating module, a protection module and a digital control module connected in sequence, the three-phase rectifier device is used for providing bus side DC voltage, the regulating module is used for regulating total excitation current, the protection module is used for guaranteeing safe operation of the device, and the digital control module is used for realizing high-precision continuous adjustment of excitation winding voltage and current.

[0060] The three-phase rectifier device, the regulating module and the digital control module are used for realizing high-precision continuous adjustment of excitation winding voltage and current, the protection module is used for guaranteeing safe operation of the device, the superconducting synchronous condenser excitation power supply device is used for guaranteeing high precision and high regulation rate of excitation current, the technical problem of imbalance of reactive power output of the superconducting synchronous condenser caused by large excitation current ripple is solved, and the reliability of the operation of the superconducting synchronous condenser is improved.

[0061] It should be understood that, in the present application, "at least one" means one or more, and "multiple" means two or more. "And / or" is used to describe the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, "A and / or B" can mean that there are three cases of only A, only B and A and B at the same time, wherein A and B can be singular or plural. The character " / " generally represents an "or" relationship between the front and rear associated objects. "At least one of the following" or the like means any combination of these items, including single item or any combination of multiple items. For example, at least one of a, b or c can mean a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b and c can be single or multiple.

[0062] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A superconducting synchronous condenser excitation power supply device, characterized in that, The device includes a three-phase rectifier, an adjustment module, a protection module, and a digital control module connected in sequence. The three-phase rectifier is used to provide DC voltage on the bus side; The adjustment module is used to adjust the total excitation current; The protection module is used to ensure the safe operation of the device; The digital control module is used to achieve high-precision continuous adjustment of the excitation winding voltage and current; The adjustment module includes a four-phase interleaved parallel buck module and a second-order LC filter module connected to each other; the four-phase interleaved parallel buck module is used to reduce excitation current ripple to adjust the total excitation current; the second-order LC filter module is used to filter out high-frequency harmonics to ensure high accuracy of load voltage and current. The digital control module is also used to control the four-phase interleaved parallel buck module to output signals by detecting the load current and voltage values, as well as the signal data generated by high-precision digital PI regulation. The power supply steps of the superconducting synchronous condenser excitation power supply device include: Step S1: Adjust the conduction angle α of the three-phase rectifier and the duty cycle D of the PWM output to adjust the magnitude of the excitation current. The specific expression is as follows: ， U1 is the output voltage of the three-phase rectifier, Ux is the grid voltage, Ud is the output voltage of the four-phase interleaved parallel buck module, Io is the excitation current, R0 is the equivalent resistance of the superconducting excitation winding, α is the conduction angle of the three-phase rectifier module, and D is the duty cycle of the PWM stage output. Step S2: Detect the actual current of the excitation winding; Step S3: After comparing the actual current of the detection excitation winding with the given value, the signal data generated by the high-precision digital PI adjustment is processed by the triangular wave modulation to output the PWM control signal of the four-phase buck circuit, wherein the PWM signal output of each phase is shifted by 90°.

2. The excitation power supply device for a superconducting synchronous condenser according to claim 1, characterized in that, The four-phase interleaved parallel buck module is also used to provide low-ripple DC current to the load winding.

3. The excitation power supply device for a superconducting synchronous condenser according to claim 1, characterized in that, The protection module includes an absorption submodule; The absorption submodule is used to absorb energy from the superconducting winding during demagnetization, thereby protecting the operational safety of the device.

4. The excitation power supply device for a superconducting synchronous condenser according to claim 1, characterized in that, The digital control module is also used to measure the voltage and current values ​​of the excitation current.

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