Design of three-phase Voltage-type Inverter Control System
ABSTRACT: Focus is Studying SPWM three-phase voltage-type AC inverter with the fundamental principles in this paper, and designing the methods and software and hardware, and complete system software and hardware. The main completion on: 1.the basic principles of VVVF technology 2. three basic principles of Frequency Control, the control scheme for the 4, 5 software and hardware design, experimental debugging. The main relevant knowledge: power electronics and motion control, computer control. Under normal circumstances in exchange for motor asynchronous speed machine, it's complicated control circuits, the system's efficiency is low. SCM using computer control the exchange of asynchronous motor Frequency Control System that has greatly simplified control circuit, the use of SPWM (SPWM) drive, the system has improved efficiency. Induction Motor Frequency Control, in the actual use of pulse width modulation (PWM), and completed FM Surge two functions. To achieve single-chip microprocessor (PWM) to control can adjust flexibly, to simplify circuit. This design by the MCS51 series of single-chip microprocessor achives PWM control, 300W in the two-phase asynchronous motor exchanges on running the experiment.
The traditional exchange of Frequency Control System from the intersection of a sine wave and the sawtooth PWM wave of constant pressure to achieve than the frequency for arrest control. As a result of this analog control system, equipment complex and difficult adjustment, and low-precision control, reliability poor, thus limiting the application of such a system. With the traditional systems, this system has the following characteristics: a new type of large-scale ASIC PWM wave, the wave stability, accuracy and reliability of a significant increase in SCM (8031 CPU as the core of digital control. Circuit simple to adjust quickly to further enhance the control accuracy.
Keywords:Three-Phase PWM voltage rectifier, Frequency Control, SCM, AC motor, computer control