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Quasi-Z-Source Three-Phase Voltage Source Inverter with Virtual Space Vector Modulation to Increase the Voltage Gain and for the Reduction of Common Mode Voltage

Nanda Debalina, Syam Prasid, Mukherjee Kaushik

Power Electronics and Drives

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2024

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Vol. 9 (44)

272--291

EN

A quasi-Z-source network is used to boost the DC bus voltage of a voltage source two-level H-bridge inverter to increase the voltage gain. With the increase in the DC bus voltage, the common mode voltage (CMV) also increases. The CMV is reduced using virtual space vector pulse width modulation (SVPWM). Due to the presence of a quasi-Z-source network, the expression of the CMV changes significantly with respect to the conventional voltage source two-level H-bridge inverter fed from a pure DC supply. In this paper, a detailed analysis of the origin of the CMV for the quasi-Z-source two-level H-bridge inverter is presented. Additionally, it is shown how the CMV is affected for a DC input supply taken from a three-phase diode bridge rectifier. The work also details the scheme for suitable placement of shoot-through time intervals required for boosting within the non-active time intervals in virtual SVPWM. The simulation and experimental results show the scheme is effective in increasing the voltage gain and reducing the CMV arising at the third harmonic of the desired output frequency by at least 33.33%.

2

Minimisation of AC Grid Side Input Power Factor Angle for Three-phase AC to Three-phase AC Matrix Converter under Varying Load

Basak Abhinandan, Syam Prasid, Mukherjee Kaushik

Power Electronics and Drives

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2024

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Vol. 9 (44)

205--219

EN

Minimisation of AC grid side input power factor angle for a ‘matrix converter (MC)’ improves the efficiency of the grid. Input volt-ampere requirement is minimum if the current drawn by the ‘MC’ is sinusoidal and input displacement power factor (IDPF) is unity. A MC is inherently capable of maintaining a unity displacement power factor (UDPF) angle at its input terminals. However, the input currents drawn from the grid are not sinusoidal. The high-frequency ripples are suppressed by input current filters (ICFs).These filters additionally introduce a leading phase angle for the current which varies with the loading. This phase lead can be compensated by adjusting the angle between the input current space vector and the input voltage space vector of the MC. The computation of this adjustment angle depends on the estimation of power losses in the switching devices. A simple method is proposed in this paper to estimate the switching losses without measuring device voltages and currents using the perturbation technique. The perturbation logic depends on input current, instantaneous active and reactive power computed at regular intervals of time. The proposed method effectively minimises the IDPF angle very close to zero. The experimental results are included for validation.

3

A Study on Various Causes of Low Frequency Components in Common Mode Voltage of a Space Vector Pulse Width Modulated Three–Phase Quasi–Z–Source H–Bridge Inverter Fed from a Three–Phase Diode Bridge Rectifier

Nanda Debalina, Syam Prasid, Mukherjee Kaushik

Power Electronics and Drives

|

2024

|

Vol. 9 (44)

142--160

EN

The presence of low frequency components in the common mode voltage can cause harmful electromagnetic interference. A critical study on various causes of low frequency components in the common mode voltage of a space vector pulse width modulated Quasi–Zsource three–phase H–bridge voltage source inverter fed from a three–phase diode bridge rectifier is presented in this paper. The Quasi–Z–source network is utilized in boosting the rectified dc voltage which increases the overall voltage gain. The study considers the effect of boosting on the low frequency components. The input three-phase diode bridge rectifier has its influence in modulating the instantaneous common mode voltage and contributes low frequency components. The unbalanced three-phase supply can contribute additionally ac supply frequency component in the common mode voltage. The major contribution of this paper is the analytical, simulated and experiment-based study on various causes of the low frequency common mode voltages due to the combined action of the input non-ideal three phase grid, the front-end diode bridge rectifier as well as the load-end Z-source H-bridge three-phase inverter feeding a three-phase inductive load, while operated through a space vector pulse width modulation strategy.