Traditional Z-source Inverter Research Articles

A SVPWM Method Based on Z-Source Three-Level Inverter

Compared to the traditional dual Z-source inverter, Z-source inverter with a signal X-shaped LC impedance network has advantages of lower cost and an easier modulating algorithm. Based on the three-level single Z-source inverters, this paper proposed a suitable SVPWM scheme, which include vector region judgment, send order determine, and synthetic time calculation. It is available to achieve inductive voltage boosting by inserting the shoot-through vectors appropriately, while simultaneously provide a good performance on output with a correct volt-second average. The theoretical concepts discussed are verified by simulation results.

Z -source-based multilevel inverter with reduction of switches

This study presents a new inverter topology based on mixture of cascaded basic units and one H-bridge unit. The basic unit includes one Z source, one DC voltage source and two switches generating two voltage levels. The cascaded basic units produce positive and zero-voltage levels and in the same time suggested inverter obtains positive, zero- and negative voltage levels, as a result the number of power semiconductor switches is reduced with respect to traditional multilevel inverters. In this topology, output voltage amplitude is not limited to DC sources voltage summation similar to traditional cascaded multilevel inverters and can be boosted with Z network shoot-through state control; therefore other DC/DC converters are not needed and it is more reliable against short circuit. Besides as compared with traditional Z-source inverter, total harmonic distortion of injected voltage is decreased in the suggested inverter topology. The performance of proposed topology and its controller are validated with simulation results using MATLAB/SIMULINK software and the validity of the proposed multilevel inverter-based Z source is verified by experimental results.

Performance Improvement of Z-Source Inverter-Fed Induction Motor Drives Using Modified Voltage Space Vector

In traditional Z-source inverter (ZSI) fed induction motor drives, the Z-source capacitor voltage and the motor terminal voltage are controlled by the shoot-through duty ratio and the modulation index, respectively. Modified voltage space vector has been proposed to improve motor terminal voltage control with effective DC boost in the DC link. For the same shoot-through duty ratio, modified voltage space vector provides better voltage boost in the DC link with reduced harmonics in the load side than the traditional voltage space vector. This paper presents an integrated control technique to minimise the electromagnetic torque ripples in the rotor of the ZSI-fed induction motor drives using modified voltage space vector. To improve the stability of the overall drive system, the motor terminal voltage alone is sensed instead of sensing the Z-source capacitor voltage and motor terminal voltage independently. This provides a single-stage controller for motor drive systems. The proposed induction motor drive system provides a better ride-through capability during voltage sags, better line harmonic profile, and minimisation of the torque ripples in the rotor. The proposed control technique is simulated using MATLAB/Simulink software, and analysis and experimental results have been presented to validate them.

Improved Z-Source Inverter With Reduced Z-Source Capacitor Voltage Stress and Soft-Start Capability

This paper proposes an improved Z-source inverter topology. Compared to the traditional Z-source inverter, it can reduce the Z-source capacitor voltage stress significantly to perform the same voltage boost, and has inherent limitation to inrush current at startup. The control strategy of the proposed Z-source inverter is exactly the same as the traditional one, so all the existing control strategy can be used directly. A soft-start strategy is also proposed to suppress the inrush surge and the resonance of Z-source capacitors and inductors. The operation principle of the proposed topology and comparison with the traditional topology are analyzed in detail. Simulation and experimental results are given to demonstrate the new features of the improved topology.