Research On The Redundant Control Technology Of Multilevel Inverter Based On SVPWM

With the increasing demand of energy and the reduce of fossil resources, the Solar,thewind, the tidal, and the geothermal energy will be the important new source of energy,inverting technology is the key technology to develop those new kind of energies.High-voltage high-power multilevel-inverter has become a hot area of research in the fieldof electrical engineering due to its low pressure requirements, high equivalent switchingfrequency,without dynamic pressure, as well as preferably output waveform,and has beenwidely used in the field of electric power project, petrifaction, transportation and architecture.Although multilevel-inverter has so many virtues,it also has drawbacks such as complicatedstructure, more electronic devices needed and so on. The complexity of the structure and theincrease of the number of the devices needed invreasing the failure rate correspondingly, notonly increase the running and maintenance costs of the inverter,but also reduced the reliabilityof the whole system, affecting the quality and safety of the production seriously. In addition,in electricity, transportation, aerospace, military industry, mining and other fields, therequirement of continuous and reliable operation is extremely strict, seriously restricting theapplication of the multilevel inverter. therefore, the reliability of the multilevel inverter hasbecome one of the bottlenecks hinder of its development and application, and an urgentproblem to be solved.Based on the SVPWM control algorithm,take the diode-clamped three-level inverter asresearch object, put forward a kind of redundant control algorithm based on SVPWM.Tree-level inverter can output three electrical level each phase, when a switching device ofone phase fall in short circuit failure or open circuit failure, the the fault phase would outputless electrical level.It can be known that the choose of basic vectors doesn’t exclusively by thetheory of Synthesising the reference vector, that means, in some failure cases, the referencespace voltage vector still can be synthesized, the inverter can be maintained running, this isthe basic theory of redundancy control algorithm.Introduce the algorithm and realization of SVPWM firstly, then analyze the failures may occur during the running Of NPC three-level inverter. Then take three typical faults asexample, analyze its redundancy control algorithm,and proposed the corresponding redundantcontrol strategy.Simulating and analyzing the redundancy control of inverter underMATLAB/Simulink, verifying the validity of the redundancy control algorithm proposed.Finally, build the experiment platform of NPC three-level inverter under the condition oflaboratory, simulate short circuit and open circuit fault of the inverter power switch deviceartificially, take redundant control experiments.The experimental results show that theproposed control algorithm can maintain the inverter running under fault state, verify thevalidity and feasibility of the redundancy control algorithm proposed. The redundancy controlalgorithm improves the reliability of the inverter greatly.