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A three-level three-phase power conversion device that can actively balance the neutral point clamp voltage

A technology of neutral point clamping and three-phase power supply, which is applied in the direction of output power conversion device, AC power input conversion to DC power output, electrical components, etc., and can solve multi-harmonic, control complexity, strong electromagnetic interference, etc. question

Inactive Publication Date: 2015-08-19
张翔
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its shortcoming is that when controlling the neutral line current, the method of changing the ratio of the voltage vector will cause the output line voltage and part of the common mode voltage to degenerate into the line voltage and the output line voltage of the two-level PWM inverter. The common mode voltage is the same, which not only brings the complexity of control, but also produces more harmonics and strong electromagnetic interference

Method used

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  • A three-level three-phase power conversion device that can actively balance the neutral point clamp voltage
  • A three-level three-phase power conversion device that can actively balance the neutral point clamp voltage
  • A three-level three-phase power conversion device that can actively balance the neutral point clamp voltage

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Embodiment 1

[0021] Such as figure 2 It is a circuit diagram showing the main circuit configuration of the three-level inverter device with the device for suppressing the neutral point current shift of the present embodiment. Such as figure 2 As shown, this example is composed of two parts, the first part is a three-phase neutral point clamped three-level PWM inverter device, the second part is a device that actively balances the neutral point clamping voltage, and the active balance The neutral point clamp voltage device connects the high-frequency switching element 1 in series between the positive bus and the neutral line, connects the high-frequency switching element 2 in series between the neutral line and the negative bus, and connects the two high-frequency switching elements in parallel for freewheeling A diode 3 and an inductor 4 are connected in series between the two high-frequency switching elements and the neutral point c of the three-phase neutral-point clamped three-level ...

Embodiment 2

[0028] Second, refer to Figure 6 A three-level three-phase power conversion device capable of actively balancing neutral point clamp voltages according to Embodiment 2 of the present invention will be described. Figure 6 It is a circuit diagram showing a main circuit configuration of a three-level three-phase power conversion device capable of actively balancing neutral point clamp voltages according to Embodiment 2 of the present invention. The difference between the three-level three-phase power conversion device that can actively balance the neutral point clamp voltage in this embodiment and the three-level three-phase power conversion device that can actively balance the neutral point clamp voltage in the above embodiment is that: Between the busbar and the negative busbar are connected 3 devices for actively balancing the neutral point clamping voltage described in the above example, and each device for actively balancing the neutral point clamping voltage is in 2 high ...

Embodiment 3

[0030] Another three-level three-phase power conversion device capable of actively balancing the neutral point clamp voltage of the present invention is described. Figure 7 It is a circuit diagram showing the main circuit structure of the three-level three-phase power conversion device capable of actively balancing the neutral point clamp voltage of this embodiment. The difference between the three-level three-phase power conversion device that can actively balance the neutral point clamp voltage in this embodiment and the three-level three-phase power conversion device that can actively balance the neutral point clamp voltage in the above embodiment is that: When the power supply of the phase-neutral point clamped three-level PWM inverter device is a rectified input, the positive bus of the device that actively balances the neutral point clamped voltage and the three-phase neutral point clamped three-level PWM inverter A diode is connected in series between the positive busb...

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Abstract

The invention provides a three-level three-phase power source transformation device capable of initiatively balancing a clamp voltage of neutral points and relates to a three-level neutral point clamp type PWM (Pulse-Width Modulation) inverter device which is one of power conversion devices of a connecting system, and a control (balance) device which is used in the three-level neutral point clamp type PWM inverter device and controls the voltage (current) at the neutral points of two capacitors connected in series between a positive bus and a negative bus, wherein the device consists two part devices, the first part device is of a three-phase neutral point clamp type PWM inverter device, the second part device is of a device for restraining the voltage of the natural point from deviating, the second part device is connected with the neutral point of the first part device by virtue of a serial inductor, and the device for restraining the voltage of the natural point from deviating can be used for efficiently restraining the change of the potential at the neutral point of the three-phase neutral point clamp type PWM inverter device, therefore, the safety can be improved, and the quality of output voltage can be enhanced.

Description

technical field [0001] The present invention relates to power conversion devices such as inverters and servo drives for variable-speed drive motors, three-level neutral point clamp type PWM (pulse width modulation) inverter devices as one of the power conversion devices of connection systems, and The neutral point voltage (current) balancing device between two capacitors connected in series between the positive bus bar and the negative bus bar is used in the three-level neutral point clamped PWM inverter device. Background technique [0002] Such as figure 1 It is a circuit diagram showing the main circuit configuration of a three-level neutral point clamp type PWM inverter device. The three-level neutral-point clamped PWM inverter device is composed of two capacitors 7 , three-phase output terminals UVW, 12 switching elements, and 18 diodes 9 . In this three-level neutral point clamped PWM inverter device, the switching element 8 1 ,8 2 When conducting, the output termi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/487H02P27/08
Inventor 张翔
Owner 张翔