Auxiliary power supply system of high-voltage frequency converter power unit

Abstract

The utility model provides an auxiliary power supply system of a power unit of a high-voltage frequency converter, which relates to the technical field of high-voltage frequency converters and comprises a single-phase isolation transformation unit, the input end of the single-phase isolation transformation unit is connected with the wire inlet end of the power unit in parallel, and the output end of the single-phase isolation transformation unit is connected with a rectifying circuit unit. The rectifying circuit unit is used for converting alternating current output by the single-phase isolation transformation unit into first direct current voltage and outputting the first direct current voltage; the isolation converter is connected with the output end of the rectifying circuit unit and the plurality of high-frequency isolation transformers, and is used for converting the first direct-current voltage into a plurality of paths of high-voltage isolated IGBT driving voltages to be supplied to the high-frequency isolation transformers; and the high-frequency isolation transformer converts the high-frequency pulse voltage into an isolation pulse power supply as a driving power supply to be output to a driving unit in the power unit. The driving power supply has the advantages of being simple in structure, easy to achieve high voltage isolation of the driving power supply, low in cost and not affected by high direct current bus voltage.

Description

Technical Field

[0001] The utility model relates to the technical field of high-voltage frequency converters, in particular to an auxiliary power supply system of a power unit of a high-voltage frequency converter. Background Art

[0002] Large-capacity high-voltage inverters are widely used in the fields of steam turbine electrification (LNG equipment), BEST small machines, compressed air energy storage equipment, etc. The power unit, as an important component of the high-voltage inverter, controls the high-voltage IGBT to output a power supply with adjustable voltage and frequency to achieve functions such as soft start and variable frequency speed regulation. The reliability of the power unit is particularly important, which is directly related to the reliability of the inverter. Using 3300V and above high-voltage IGBT modules to increase the output voltage of the module and thus reduce the number of cascaded modules is an effective way to improve the reliability of large-capacity high-voltage inverters. With the increase of the voltage of the IGBT module, the input voltage and bus voltage of the module are also increased accordingly, and it is more difficult to realize the auxiliary power supply of the power unit.

[0003] There are two solutions in the prior art:

[0004] Solution 1 is that the driving power supply of the IGBT in the power unit is realized by a DC / DC high-frequency power supply with multi-channel isolated output. This solution is relatively easy to implement and has low cost. It is widely used in IGBTs of 1700V and below. Figure 1 (Originally cited from "A power supply system and power unit of a power unit" patent number: ZL201720774764.5) as shown:

[0005] Solution 2 is to take power from the unit DC bus voltage, and then use DC / DC to realize multi-channel isolated power supply to power the IGBT. This solution is also relatively mature, and some high-voltage inverter manufacturers use this solution in IGBTs of 1700V and below. Figure 2 (Originally quoted from "A high-voltage inverter power unit powered by a DC bus" authorization announcement number: CN216904680) as shown.

[0006] Both Schemes 1 and 2 directly power the IGBT driver through DC / DC, and provide a higher isolation voltage and sufficient power through the DC / DC conversion unit of module 4, which will greatly increase the size of the transformer and significantly increase the processing difficulty, making it difficult to implement.

[0007] Since the bus voltage is too high, the DC / DC conversion using the bus power supply has extremely high voltage requirements for the switch devices. The switch devices that can be directly used on the market are limited, so Solution 2 is difficult to implement and has high costs. In addition, when a serious fault occurs in the power unit, the unit incoming line fuse will generally blow, and the DC bus will lose the ability to supply power to the power system, and the power system will be paralyzed. Utility Model Content

[0008] In view of the problems existing in the prior art, the utility model provides an auxiliary power supply system for a high-voltage inverter power unit, which is applied to a high-voltage inverter composed of cascaded power units, each of which is connected to an auxiliary power supply system, and the auxiliary power supply system includes:

[0009] A single-phase isolation transformer unit, wherein the input end of the single-phase isolation transformer unit is connected in parallel to the incoming line end of the power unit, and the output end of the single-phase isolation transformer unit is connected to a rectifier circuit unit, and the rectifier circuit unit is used to convert the alternating current output by the single-phase isolation transformer unit into a first direct current voltage and output it;

[0010] An isolation converter is connected to the output end of the rectifier circuit unit and multiple high-frequency isolation transformers, and is used to convert the first DC voltage into multiple high-voltage isolated IGBT drive voltages and output them to each of the high-frequency isolation transformers. The high-frequency isolation transformer converts the IGBT drive voltage into an isolated pulse power supply as a drive power supply and outputs it to the drive unit in the power unit.

[0011] Preferably, the single-phase isolation transformer unit is an isolation transformer, the line input end of the power unit is a three-phase input, and the isolation transformer comprises:

[0012] The primary winding of the transformer is connected to any two phases of the three-phase input, and the output end of the secondary winding of the transformer is connected to the input end of the rectifier circuit unit.

[0013] Preferably, the power unit further includes a fan, and the isolation transformer further includes a secondary second winding, and the output end of the secondary second winding is connected to the fan to provide AC power for the fan.

[0014] Preferably, the power unit also includes a unit controller, and the isolation converter is also connected to a unit controller power conversion unit, and the isolation converter is also used to convert the first DC voltage into a third DC voltage to supply the unit controller power conversion unit to power the unit controller.

[0015] Preferably, an electrolytic capacitor is further included, and the electrolytic capacitor is connected in parallel to the output end of the rectifier circuit unit, and is used to filter the first DC voltage and output the filtered first DC voltage to the isolation converter.

[0016] Preferably, the isolation converter is a DC-to-DC converter, and the DC-to-DC converter includes a high-frequency switching transformer, and the high-frequency switching transformer is used to convert the first DC voltage into multiple high-voltage isolated IGBT drive voltages.

[0017] Preferably, it also includes a plurality of driving power conversion units, which are respectively connected to one of the high-frequency isolation transformers and a driving unit in the power unit, and are used to convert the isolated pulse power into the driving power output of the driving unit.

[0018] The above technical solution has the following advantages or beneficial effects:

[0019] The single-phase isolation transformer unit is used to take power from the input end of the power unit for rectification, and the isolation converter + high-frequency isolation transformer is used to generate a high-isolation pulse power supply as the driving power supply of the driving unit of the power unit. This auxiliary power supply system is not only simple in structure, but also easy to achieve high-voltage isolation of the driving power supply, low in cost, and not affected by high DC bus voltage. It can stably provide working voltage to the unit controller and multiple driving units in the power unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram corresponding to solution 1 in the prior art;

[0021] Figure 2 It is a structural schematic diagram corresponding to the second solution in the prior art;

[0022] Figure 3 The present invention is a schematic structural diagram of an auxiliary power supply system of a high-voltage inverter power unit in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0023] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The present invention is not limited to the implementation mode, and other implementation modes may also fall within the scope of the present invention as long as they meet the purpose of the present invention.

[0024] In a preferred embodiment of the utility model, based on the above problems existing in the prior art, an auxiliary power supply system of a high-voltage inverter power unit is provided, which is applied to a high-voltage inverter composed of cascaded power units, and each power unit is connected to an auxiliary power supply system, such as Figure 3 As shown, the auxiliary power system includes:

[0025] A single-phase isolation transformer unit 1, the input end of the single-phase isolation transformer unit 1 is connected in parallel to the incoming line end of the power unit, and the output end of the single-phase isolation transformer unit 1 is connected to a rectifier circuit unit 2, which is used to convert the alternating current output by the single-phase isolation transformer unit 1 into a first direct current voltage and output it;

[0026] The isolation converter 3 is connected to the output end of the rectifier circuit unit 2 and multiple high-frequency isolation transformers 4, and is used to convert the first DC voltage into multiple high-voltage isolated IGBT drive voltages and output them to each high-frequency isolation transformer 4. The high-frequency isolation transformer 4 converts the IGBT drive voltage into an isolated pulse power supply as a drive power supply and outputs it to the drive unit in the power unit.

[0027] The single-phase isolation transformer unit 1 is an isolation transformer. The incoming line end of the power unit is a three-phase input. The isolation transformer includes:

[0028] The primary winding of the transformer is connected to any two phases of the three-phase input, and the output end of the secondary winding of the transformer is connected to the input end of the rectifier circuit unit 2.

[0029] Specifically, in this embodiment, the problems existing in the prior art of the auxiliary power supply system in the power unit, such as large size, high processing difficulty, and serious failure of the power unit causing the power supply system to be paralyzed, are addressed. An auxiliary power supply system for a large-capacity high-voltage inverter power unit is provided, which can be used for the auxiliary power supply design of an inverter power unit with IGBT of 3300V and above. Power is taken from the input end of the power unit for rectification through a single-phase isolation transformer unit, and a high-isolation pulse power supply is generated through an isolation converter + high-frequency isolation transformer as the IGBT drive power supply of the power unit. The auxiliary power supply system is not only simple in structure, but also easy to achieve high-voltage isolation of the drive power supply, low in cost, and not affected by high DC bus voltage. The operating voltage can be stably provided to the unit controller and multiple drive units in the power unit.

[0030] A preferred embodiment of the present utility model is as follows Figure 3 As shown, it also includes a plurality of driving power conversion units 5, which are respectively connected to a high-frequency isolation transformer 4 and a driving unit in a power unit, and are used to convert the isolated pulse power into the driving power output of the driving unit.

[0031] Specifically, in this embodiment, the driving units in the power unit are all IGBTs. When a high-isolation pulse power supply is generated by the isolation converter 3 + high-frequency isolation transformer 4 as the IGBT driving power supply of the power unit, due to the differences between different IGBTs, a corresponding driving power conversion unit is also provided to convert the high-isolation pulse power supply into a driving working voltage suitable for different IGBTs.

[0032] In a preferred embodiment of the utility model, the power unit further includes a fan 6, and the isolation transformer 1 further includes a secondary second winding, and the output end of the secondary second winding is connected to the fan to provide AC power for the fan.

[0033] In a preferred embodiment of the present invention, the power unit further includes a unit controller. Figure 3As shown, the isolation converter 3 is also connected to the unit controller power conversion unit 7, and the isolation converter is also used to convert the first DC voltage into a third DC voltage to supply the unit controller power conversion unit to power the unit controller.

[0034] Specifically, in this embodiment, the auxiliary power supply system not only provides driving power to the IGBT in the power module, but also provides power to the fan in the power unit and the unit controller of the power unit.

[0035] A preferred embodiment of the utility model further includes an electrolytic capacitor (not shown in the figure), which is connected in parallel to the output end of the rectifier circuit unit and is used to filter the first DC voltage and output the filtered first DC voltage to the isolation converter.

[0036] In a preferred embodiment of the utility model, the isolation converter is a DC-to-DC converter, which includes a high-frequency switching transformer, and the high-frequency switching transformer is used to convert a first DC voltage into a multi-channel high-voltage isolated IGBT drive voltage.

[0037] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of this specification and illustrations should be included in the protection scope of the present invention.

Claims

1. An auxiliary power supply system for a high-voltage inverter power unit, characterized in that: Applicable to a high-voltage frequency converter composed of cascaded power units, each of which is connected to an auxiliary power supply system, which includes: A single-phase isolation transformer unit, wherein the input end of the single-phase isolation transformer unit is connected in parallel to the incoming line end of the power unit, and the output end of the single-phase isolation transformer unit is connected to a rectifier circuit unit, and the rectifier circuit unit is used to convert the alternating current output by the single-phase isolation transformer unit into a first direct current voltage and output it; An isolation converter is connected to the output end of the rectifier circuit unit and multiple high-frequency isolation transformers, and is used to convert the first DC voltage into multiple high-voltage isolated IGBT drive voltages and output them to each of the high-frequency isolation transformers. The high-frequency isolation transformer converts the IGBT drive voltage into an isolated pulse power supply as a drive power supply and outputs it to the drive unit in the power unit.

2. The auxiliary power supply system according to claim 1, characterized in that: The single-phase isolation transformer unit is an isolation transformer, the line input end of the power unit is a three-phase input, and the isolation transformer includes: A primary winding of a transformer, wherein the primary winding of the transformer is connected to any two phases of the three-phase input, and the output end of the secondary winding of the transformer is connected to the input end of the rectifier circuit unit.

3. The auxiliary power supply system according to claim 2, characterized in that: The power unit further includes a fan, and the isolation transformer further includes a secondary second winding, and the output end of the secondary second winding is connected to the fan to provide an AC power supply for the fan.

4. The auxiliary power supply system according to claim 1, characterized in that: The power unit also includes a unit controller, and the isolation converter is also connected to a unit controller power conversion unit, and the isolation converter is also used to convert the first DC voltage into a third DC voltage to supply the unit controller power conversion unit to power the unit controller.

5. The auxiliary power supply system according to claim 1, characterized in that: It also includes an electrolytic capacitor, which is connected in parallel to the output end of the rectifier circuit unit and is used to filter the first DC voltage and output the filtered first DC voltage to the isolation converter.

6. The auxiliary power supply system according to claim 1, characterized in that: The isolation converter is a DC-to-DC converter, which includes a high-frequency switching transformer, and the high-frequency switching transformer is used to convert the first DC voltage into multiple high-voltage isolated IGBT driving voltages.

7. The auxiliary power supply system according to claim 1, characterized in that: It also includes a plurality of driving power conversion units, which are respectively connected to one of the high-frequency isolation transformers and a driving unit in the power unit, and are used to convert the isolated pulse power into the driving power output of the driving unit.

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