Z source reverser and soft start method

A source inverter and soft start technology, applied in the direction of converting AC power input to DC power output, output power conversion device, electrical components, etc., can solve the problem of short circuit of input voltage source, distortion of output waveform, circuit damage of switching tube, etc. Problems, to avoid large voltage and current, small capacitor voltage stress, safe and reliable work

CN101267168AInactive Publication Date: 2008-09-17NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2008-09-17
Estimated Expiration
Not applicable · inactive patent

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Abstract

The present invention provides a z-source inverter and its soft starting method, belonging to power electronic converter. The inverter main circuit is composed of a DC voltage source, a three-phase inverter bridge, a z-source network, a power diode, characterized in that the positive end of the three-phase inverter bridge is connected to the cathode of the DC voltage source, the negative end of the three-phase inverter bridge is connected to the Z source network. Compared with the voltage source type and the current source type inverter, the Z source inverter realizes pressure raising change function, and the upper and the lower switch tubes of the same bridge arm are directly passing, so the dead zone does not need, the circuit structure is simple, having high credibility. Compared with the traditional Z source inverter, the capacitor voltage of the Z source network in the Z source inverter has small stress, and realizing the soft start of the transformer, avoiding the problems of large voltage and current when the traditional Z source inverter starts, the work of the transformer is safe and credible, and having light volume and weight.
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Description

1. Technical field

[0001] The Z-source inverter and its soft-start method involved in the present invention belong to power electronic converters. 2. Background technology

[0002] Inverters are widely used in motor drives, uninterruptible power supplies, induction heating, static var generators and compensators, and active filtering. Traditional inverter circuit topologies include voltage source inverters and current source inverters.

[0003] attached figure 1 It is the main circuit of the voltage source inverter. The circuit is composed of a DC voltage source and a three-phase inverter bridge. The inverter bridge is composed of six power switches. Each power switch is connected in parallel with a body diode to provide bidirectional current flow and unidirectional voltage blocking capability. The voltage source inverter has the following defects: 1) The output AC voltage is lower than the DC bus voltage, so the voltage source inverter is essentially a step-down inverter...

Examples

Embodiment Construction

[0016] attached Figure 4 Is the Z source inverter main circuit. Compared with the traditional voltage source inverter, this inverter replaces some of the traditional zero vectors with direct zero vectors to realize the function of boosting. On the other hand, the impact of the through zero vector and the traditional zero vector on the output is the same, so the addition of the through zero vector will not affect the output waveform. The converter controls the capacitor voltage of the Z source network by controlling the direct duty cycle of the inverter bridge arm, and controls the output voltage by controlling the modulation ratio. When the converter starts, it controls the direct duty cycle of the inverter bridge arm from Slowly increase from zero to the rated value, so as to realize the soft start of the converter and avoid the overshoot of the inductor current and capacitor voltage in the converter. Specifically, it includes the following four soft start methods: 1. The m...