A novel fundamental voltage amplitude linear output control strategy of SVPWM inverter in the overmodulation region

Generally, the overmodulation techniques for space vector pulse width modulation (SVPWM) inverters need store lots of date in the controller beforehand, which makes a huge memory while the control resolution is not perfect. Based on amplitude control of the reference voltage vector and the vertex voltage vectors, this paper presents a novel digital over-modulation control strategy for SVPWM inverters, which can manage the transition from the linear control range to six-step operation smoothly. With avoiding the necessity of the stored data implementation, this strategy is simple and very suitable for practical digital implementation. The mathematic analyses show that the output fundamental voltage amplitude is linear proportional to the modulation index. In addition, this paper analyses the harmonic components, and the total harmonic distortion (THD) of the output voltage is compared with that of other strategy too. Both math analyses and experimental results, obtained by DSP board, verify that this strategy is very useful for the induction motor with the linear fundamental voltage output gain, low THD and simple application.