High-power drilling water injection pump frequency converter based on power decoupling circuit

Abstract

The utility model discloses a high-power drilling water injection pump frequency converter based on a power decoupling circuit, and belongs to the technical field of electric power transmission. The high-power drilling water injection pump frequency converter comprises a power decoupling circuit (1), a rectifier (2), an inverter (3), a direct-current reactor (4) and a direct-current filter capacitor (5), the power decoupling circuit (1) comprises a power tube S1, a power tube S2, a decoupling inductor Lx and a decoupling capacitor Cx, driving pulse signals of the power tubes S1 and S2 are provided through a controller, the pulsating power between a power grid and a load can be eliminated, and the direct-current filter capacitor (5) is connected with the rectifier (2). Therefore, the DC bus voltage fluctuation and the grid-side current harmonic wave are reduced. Compared with a traditional water injection pump frequency converter power unit, the water injection pump frequency converter power unit has the advantages that the power decoupling circuit with small capacity is added, mismatching power between a power grid and a load is eliminated, and grid-side current harmonics are reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric transmission, and in particular relates to a high-power drilling water injection pump frequency converter based on a power decoupling circuit. Background Art

[0002] With the rapid development of power electronics and computer technology in recent years, electric drive technology based on power devices and power converter control has been increasingly widely used in all aspects of the national economy. Traditional high-power drilling water injection pumps are generally driven by fixed-speed induction motors. Implementing frequency conversion for high-power drilling water injection pumps can improve operating efficiency, reduce mechanical stress of water injection pumps and increase equipment life, which is in line with the current social and economic development direction of low carbonization, energy saving and consumption reduction.

[0003] However, the drilling water injection pump is a multi-cylinder plunger pump. Since this type of plunger pump adopts a crankshaft hydraulic cylinder structure, its load torque has very strong periodic fluctuations. After being driven by a traditional AC-DC voltage source inverter, the strong fluctuations in the load torque will cause large voltage fluctuations on the DC bus of the motor variable frequency drive system, causing a sharp increase in the harmonic current on the grid side of the diode rectifier, which can easily cause various faults in adjacent equipment, such as abnormal temperature rise, motor insulation breakdown, capacitor overcurrent and other problems.

[0004] Therefore, in order to reduce the negative effects caused by the strong fluctuating load of the water injection pump, it is necessary to improve the design of the water injection pump inverter. When the load torque of the inverter system fluctuates greatly, the DC bus voltage fluctuation is suppressed and the grid-connected harmonic current is reduced, effectively reducing the risk of irreversible failure of the drilling water injection pump inverter and its auxiliary equipment. Utility Model Content

[0005] In view of the shortcomings of the prior art, the utility model proposes a high-power drilling water injection pump inverter based on a power decoupling circuit. By adding a power decoupling circuit with a compact structure and small capacity, the problems of large bus voltage fluctuations and large grid-connected harmonic current of the water injection pump inverter are solved, and the risk of failure of the water injection pump inverter system and its auxiliary equipment is effectively reduced.

[0006] The technical solution adopted by the utility model is: a high-power drilling water injection pump inverter based on a power decoupling circuit, the drilling water injection pump inverter comprising a power decoupling circuit, a rectifier, an inverter, a DC reactor and a DC filter capacitor; the rectifier, the inverter, the DC reactor and the DC filter capacitor constitute the main circuit of the AC-DC voltage source inverter, and the power decoupling circuit is connected to the DC bus.

[0007] The power decoupling circuit includes a power tube S 1 , power tube S 2 , decoupling inductor Lx and decoupling capacitor C x , decoupling inductor L x One end is connected to the positive pole of the DC bus, and the other end is connected to the power tube S 1 , power tube S 2 Connection, power tube S 2 With the decoupling capacitor C x After connecting in series, with the power tube S 1 Connect in parallel, one end of the parallel connection is connected to the decoupling inductor L x Connect one end to the negative pole of the DC bus.

[0008] The utility model provides a power tube S through a controller 1 And power tube S 2 The driving pulse signal generates a power flow with the same load cycle and opposite phase as the water injection pump in the decoupling capacitor and decoupling inductor branches, which can eliminate the pulsating power between the power grid and the load and reduce the DC bus voltage fluctuation and grid-side current harmonics.

[0009] Preferably, the power tube S of the power decoupling circuit 1 And power tube S 2 IGBT or MOSFET power modules can be used.

[0010] Beneficial effects: The utility model generates a power flow with the same load cycle and opposite phase as the water injection pump through a power decoupling circuit. When the load torque of the inverter system fluctuates greatly, it can suppress the DC bus voltage fluctuation and reduce the grid-connected harmonic current, effectively reducing the risk of irreversible failure of the drilling water injection pump inverter and its auxiliary equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The utility model is a schematic diagram showing the positional relationship and connection relationship of various parts of the high-power drilling water injection pump frequency converter.

[0012] Figure 2 This is the schematic diagram of the power decoupling circuit.

[0013] Figure 3 It is a schematic diagram of the power decoupling principle.

[0014] 1—power decoupling circuit; 2—rectifier; 3—inverter; 4—DC reactor; 5—DC filter capacitor. DETAILED DESCRIPTION

[0015] The technical solution of the utility model is described in detail below with reference to the accompanying drawings and specific implementation methods:

[0016] like Figure 1As shown, a high-power drilling water injection pump inverter based on a power decoupling circuit, the inverter includes a power decoupling circuit 1, a rectifier 2, an inverter 3, a DC reactor 4 and a DC filter capacitor 5; the rectifier 2, the inverter 3, the DC reactor 4 and the DC filter capacitor 5 constitute the main circuit of the AC-DC voltage source inverter, and the power decoupling circuit 1 is connected to the DC bus in parallel.

[0017] like Figure 2 As shown, the power decoupling circuit 1 includes a power tube S 1 , power tube S 2 , decoupling inductor L x and decoupling capacitor C x , decoupling inductor L x One end is connected to the positive pole of the DC bus, and the other end is connected to the power tube S 1 , power tube S 2 Connection, power tube S 2 With the decoupling capacitor C x After connecting in series, with the power tube S 1 Connect in parallel, one end of the parallel connection is connected to the decoupling inductor L x Connect one end to the negative pole of the DC bus.

[0018] Figure 3 This is a schematic diagram of the working principle of the power decoupling circuit, for the water injection pump motor load T L The controller provides the power tube S 1 And power tube S 2 The driving pulse signal generates a power flow P with the same load cycle and opposite phase as the water injection pump on the decoupling capacitor and decoupling inductor branches. x , which can eliminate the pulsating power between the grid and the load, and reduce the DC bus voltage fluctuation and grid-side current harmonics.

[0019] By generating a power flow with the same load cycle and opposite phase as the water injection pump through the power decoupling circuit, the DC bus voltage fluctuation can be suppressed and the grid-connected harmonic current can be reduced when the load torque of the inverter system fluctuates greatly, effectively reducing the risk of irreversible failure of the drilling water injection pump inverter and its auxiliary equipment.

[0020] The technical means disclosed in the present utility model are not limited to the technical means disclosed in the above-mentioned implementation mode. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications are also considered to be within the protection scope of the present utility model.

Claims

1. A high-power drilling water injection pump inverter based on a power decoupling circuit, characterized in that: The drilling water injection pump frequency converter comprises a power decoupling circuit (1), a rectifier (2), an inverter (3), a DC reactor (4) and a DC filter capacitor (5); the rectifier (2), the inverter (3), the DC reactor (4) and the DC filter capacitor (5) constitute an AC / DC voltage source frequency converter main circuit, and the power decoupling circuit (1) is connected in parallel to a DC bus; The power decoupling circuit (1) comprises a power tube S1, a power tube S2, a decoupling inductor L x and decoupling capacitor C x ; The decoupling inductor L x One end is connected to the positive pole of the DC bus, and the other end is connected to the power tube S1 and the power tube S2. The power tube S2 is connected to the decoupling capacitor C x After the series connection, it is connected in parallel with the power tube S1, and one end of the parallel connection is connected to the decoupling inductor L x Connect one end to the negative pole of the DC bus.

2. A high-power drilling water injection pump inverter based on a power decoupling circuit according to claim 1, characterized in that: The power tube S1 and the power tube S2 of the power decoupling circuit (1) both adopt IGBT or MOSFET power modules.

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