Vector control scheme for general-purpose inverters

Vector control scheme for general-purpose inverters

Control plan

An asynchronous motor is a high-order, nonlinear, and strongly coupled system. The vector control method is more complicated. To determine the best control method, the dynamic and static characteristics of the system must be fully analyzed. The most important part is to establish a suitable mathematical model, which is mainly realized by means of coordinate transformation. of.

For vector control and direct torque control, the two control methods can be compared in many aspects, such as control theory, control hardware and software implementation, main circuit and peripheral circuit requirements. In view of the diversity of the prototype methods, the comparison of the two control methods is somewhat difficult. This article will present the corresponding characteristic curves, as well as a brief description of the test results. The company's vector control general-purpose inverter (15kW, called "VC inverter") and the company's direct torque control general-purpose inverter (15kW, called "DTC inverter") are selected as the prototype asynchronous motor. The vector control is based on the internal parameters of the motor. However, as the load and temperature of the motor change, the resistance of the rotor also changes, which will affect the torque of the rotor. Therefore, the motor parameters must be corrected online. The model reference adaptive method can be used, mainly The voltage model with rotor resistance is used as a reference model. The current model with rotor resistance is used as an adjustable model. The two models have the same physical meaning of output, and the error of the two model outputs constitutes a suitable adaptive law. The parameters of the adjustable model are adjusted in real time to achieve the purpose of controlling the output tracking model of the object. In the process of testing the raw data, the test environment and conditions are considered (such as ambient temperature, motor starting temperature, recorder sampling rate, etc.).