Research On Carrier Frequency For Loss Characteristics And Efficiency Optimization Of Induction Motor Variable Frequency System

The paper chooses a small induction motor variable frequency system as the research object, starting from the perspective of carrier frequency, through the study of the relationship between the each part of system loss and the carrier frequency,and using the finite element analysis software to establish the model of motor and MATLAB inverter power,which are carried out the joint simulation calculation.And a experiment platform is built to study the relationship between the parts of motor loss under power frequency and frequency conversion power supply and the carrier frequency.It is theoretically analyzed the composition of loss of the motor variable frequency system and loss of the inverter,as well as the influence factors of each part of the loss, which introduce the relationship between each part of the loss and the carrier frequency. The theory of finite element method is introduced, on this basis, frequency conversion power model is established with the MATLAB software, and all the finite element model of the motor is established.Then the simulation is carried out under the power frequency power and frequency conversion power supply, and it is concluded the loss of the system.A reversible double machine of system is adopted in the experiment of system, Motor 1 step-down start by the coupling voltage regulator, and reversible converter control is adopted to improve the starting of motor 2. It is measured each part power and loss of system with WT3000. Fristly, the two motor is measured under power frequency power supply for short circuit and no-load test, and the two motor loss is concluded, namely the copper loss, iron loss and mechanical wear. Secondly,the motor 2 short circuit and no-load loss experiment is tested under the variable frequency power supply, it is concluded the relationship curve between the motor copper loss and the carrier frequency and the curve of motor iron loss and carrier frequency.Then under the experiment of the motor frequency conversion power supply, it is concluded that the rectifier loss and inverter loss,which are added to get the wastage of the frequency converter, so that it is concluded the relationship curve between the wastage of the frequency converter and the carrier frequency. Finally, in the same experimental conditions, to test total loss of motor variable frequency system, it is concluded that the relationship between the system total loss and the carrier frequency. According to the result of simulation and experiment, the paper find the best carrier frequency system with minimum total loss, in order to improve the efficiency of motor variable frequency system, achieve the goal of efficiency optimization.