Introduction Variable frequency power supply system as an important part of the merits of their performance is directly related to the overall system security and reliability. Modern inverter power to low power, high efficiency, simple circuit which favored some obvious advantages. The circuit consists of Power Supply AC - DC - AC - filtering parts, the output voltage and current waveforms are pure sine wave, and the frequency and amplitude adjustable within a certain range.
TMS320F28335 based on the realization of this frequency digital control system design, through the effective use of TMS320F28335 rich chip hardware resources to achieve the SPWM irregular sampling, and the system using PID algorithms produce high-quality sine wave, with operations speed, high precision, good flexibility and strong ability of system expansion.
Overall system description According to different structure, variable frequency inverter power supply can be divided into direct and indirect variable frequency power into two categories. This paper studied the structure variable frequency power supply is an indirect variable frequency AC - DC - AC transformation process. First, single-phase full-bridge rectifier circuit to complete the AC - DC conversion, and then under the control of the DSP to convert DC power supply after the three-phase SPWM wave filter circuit level, the formation of a standard sine wave. Inverter system controller uses TI has introduced the industry's first floating point digital signal controllers TMS320F28335, it has a 150MHz high-speed processing capability, with 32-bit floating point processing unit, a single instruction cycle 32-bit accumulate operations to meet the application for faster code Development of advanced controllers with integrated floating-point processor performance requirements. With the previous generation's leading digital signal processors, the latest F2833x floating-point controller can not only improve the average performance of 50%, also has higher accuracy, simplifying software development, software compatible with the characteristics of fixed-point C28xTM controller. Overall system block diagram shown in Figure 1.
(1) rectifier modules: the input AC power is rectified filter for the converter to provide DC voltage ripple small.
(2) three-phase bridge inverter modules: the DC voltage is converted into alternating current. Power stage with intelligent power module IPM has simple circuit, high reliability.
(3) LC filter modules: filter out unwanted interference and signal to the standard sine wave output signal.
(4) control circuit module: The detection of the output voltage and current signals, according to some control algorithm and control strategy to produce SPWM control signals to control the IPM switch on-off so as to maintain output voltage stability, and completed by SPI Interface the input voltage signal, current signal conditioning program control. Capture unit for measuring frequency of the output signal.
(5) voltage, current detection module: Upon request, require real-time detection of line voltage and phase current changes, it needs three voltage detection and three-way current detection circuit. All of the test signal voltage follower have been isolated after the TMS320F28335 the A / D channel input.
(6) auxiliary power supply modules: the control circuit to meet certain technical requirements to provide DC power to ensure the system is reliable.
System hardware design Frequency power supply hardware consists mainly of six modules: rectifier module, IPM circuit module, IPM isolated driver modules, the output filter module, voltage detection module and TMS320F28335 digital signal processing module.
Rectifier Module
Not controlled rectifier circuit with diodes to improve the network side voltage power factor rectifier with a large capacitor from the DC voltage regulator to provide DC voltage for the inverter, the circuit consists of six rectifier diodes and the absorption power of the DC inductive load stable capacitance of the composition. I am a professional writer from China Crafts Suppliers, which contains a great deal of information about wholesale hand towel , reactive beach towel, welcome to visit!
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