Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

A kind of three-level anpc converter neutral point voltage balance control method

A control method and voltage balance technology, applied in the direction of converting AC power input to DC power output, electrical components, output power conversion devices, etc., can solve problems such as loss of practical significance, increase of output voltage harmonics, mid-point voltage fluctuation, etc.

Active Publication Date: 2019-04-02
ANHUI UNIVERSITY
View PDF4 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

One of the prerequisites for the normal operation of three-level and above ANPC topologies is that the midpoint voltage must be balanced. During SVPWM control, if the key issue of midpoint voltage balance is not considered, the midpoint voltage will be relatively large during SVPWM control. The fluctuation of the output voltage will lead to the increase of the harmonics of the output voltage and the asymmetry of the three-phase output. In severe cases, the switching devices and filter capacitors will be damaged, which will lose practical significance.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • A kind of three-level anpc converter neutral point voltage balance control method
  • A kind of three-level anpc converter neutral point voltage balance control method
  • A kind of three-level anpc converter neutral point voltage balance control method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0021] SVPWM is based on the ideal flux circle of the stator of the three-phase symmetrical motor when the three-phase symmetrical sine wave voltage is supplied as the reference standard, and the different switching modes of the three-phase converter are used for appropriate switching to form a PWM wave, and the actual flux vector formed is to track the reference flux circle. The traditional SPWM method starts from the point of view of the power supply to generate a sine wave power supply with adjustable frequency and voltage, while the SVPWM method considers the inverter system and the asynchronous motor as a whole. The model is relatively simple, and it is also convenient for the real-time control. SVPWM control is selected, and only one device is involved in each switching, so the switching loss is small; the three-phase PWM wave is directly generated by using the voltage space vector, and the calculation is simple; the voltage utilization rate is higher than that of the tr...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention relates to a method for controlling midpoint voltage balance of a three-level ANPC converter, comprising the following steps: (1), adopting a SVPWM pulse sequence to act on the three-level ANPC converter; (2), detecting the DC side capacitance of the converter in real time Voltage, get the midpoint voltage value, and compare it with the midpoint voltage reference value to determine whether the DC side capacitor needs to be charged or discharged; (3), real-time detection of the positive and negative of the three-phase load current of the converter; (4), comprehensive steps ( 2) and the detection value of step (3), dynamically adjust the duty ratio of the zero state of the switching sequence to the three-phase bridge arm in each switching cycle until the midpoint voltage is balanced, and repeat this process to maintain the midpoint voltage fluctuate within a small range. The invention can dynamically adjust the charging and discharging time of the capacitor according to the direction of the three-phase load current and the magnitude of the midpoint voltage, so that the midpoint voltage can quickly reach a balance and maintain a fluctuation within a small range.

Description

technical field [0001] The invention relates to a control strategy of a three-level converter, in particular to a midpoint voltage balance control method of a three-level ANPC converter. Background technique [0002] With the advancement of technology and the improvement of living standards, people's requirements for power quality are also constantly improving. The emergence of active neutral-point-clamped (ANPC) topology makes up for the diode-clamped topology and capacitor The shortcomings of the clamping topology are better suited for 6KV and 10kV high-voltage frequency conversion fields. ANPC multi-level converters are increasingly being used in fields such as industry and social life to provide better quality electric energy. At present, although it is common to use the SVPWM modulation method to act on the three-level ANPC converter at home and abroad, the method of controlling the midpoint voltage balance when using the SVPWM modulation method to act on the three-lev...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/487
CPCH02M7/487
Inventor 胡存刚马大俊王群京李国丽
Owner ANHUI UNIVERSITY
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products