| Uninterruptible power supply (UPS) systems have been widely used to protect sensitive loads, like PCs or medical equipment, in case of power failure. To guarantee a low total harmonic distortion (THD) of voltage under nonlinear and distortion loads, many control techniques or strategies have been widely introduced or researched.This paper presented a DSP technology based single-phase UPS system design based on the digital servo control schemes. In the UPS sine inverter design, the UPS inverter has been considered as a standard sine wave servo system and separates the controller as inner and outer loop. In the inner control loop, use state feedback control technique to replace the system pole for reducing the output wave form distortion caused by load current. On the other hand, use an integrator to reduce steady-state error between the system output and reference sine wave and stabilize the system output frequency in the outer control loop. The proposed solution, based on the output voltage and inverter's output current sensing, i.e., without load current measurement, guarantees a low harmonic distortion, stable output voltage and a high steady-state and dynamic system response performance. To demonstrate the validity of this approach, the simulation based on digital computer simulation software Simulink of MATLAB has been studied and the result proved this control ideal.Based on UPS inverter control arithmetic, this paper also described the hardware structure of TMS320F2407 digital signal processor (DSP) based UPS inverter controller which we designed. In the meanwhile, the controller software programming has beenpresented.To complex system, the work mentioned above is not far more enough. So, in the later of paper, the design of the assistant circuit for the UPS system like controller power supply circuit, systems protect circuit and inverter PWM driver circuit etc. has been described in detail.At last, the paper summarizes and prospects the whole work.
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