• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.489-500
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• 2014

This paper presents a simple modified unipolar carrier-based pulsewidth modulation (CB-PWM) strategy for the three-level neutral-point-clamped (NPC) voltage source inverter (VSI). Analytical expressions for the relationship between modulation reference signals and output voltages are derived. The proposed modulation technique for the three-level NPC VSI includes the maximum and minimum of the three-phase sinusoidal reference voltages with zero-sequence voltage injection concept. The proposed modified CB-PWM strategy incorporates a novel method that requires only of one triangular carrier wave for generate the gating pulses in three-level NPC VSI. It has the advantages of being simplifying the algorithm with no need of complex two/multi-carrier pulsewidth modulation or space vector modulation (SVM) and it's also simple to implement. The possibility of the proposed CB-PWM technique has been verified though computer simulation and experimental results.

• Journal of Electrical Engineering and Technology
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• v.11 no.3
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• pp.670-674
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• 2016

The control performance of hybrid PWM inverter using a phase current measurement is presented in this paper. The hybrid PWM technique consists of space vector pulse width modulation (SVPWM) and six-step voltage control operation. The SVPWM is performed to reduce the harmonic components in the low speed region, and the six-step modulation is applied to increase the maximum speed of the IPMSM in the high speed region. Therefore, it is possible to obtain a great performance in both the low speed range and high speed range. However, the six-step modulation cannot be completely implemented, since the inverter that includes the lag-shunt sensing method has an immeasurable current region. In this paper, a quasi-six-step modulation using a modified voltage vector is proposed. The validity and usefulness of the proposed PWM technique is verified by MATLAB/Simulink and experimental results.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1235-1243
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• 2015

This paper presents a modified Space Vector Pulse Width Modulation Technique (SVPWM), which solves the well-known problem of voltage imbalance in the capacitors of a single-phase multilevel inverter. The proposed solution is based on the measurement of DC voltage levels at each capacitor of the inverter DC bus. The measurements are then used to adjust the size of the active vectors within the SVPWM algorithm to keep the voltage waveform sinusoidal regardless of any voltage imbalance on the DC link capacitors. When a voltage deviation exceeds a predetermined hysteresis band, the correspondent voltage vector is restricted to restore the voltage level to an acceptable threshold. Hence, the need for external voltage regulators for the voltage capacitors is eliminated. The functionality of the proposed algorithm is successfully demonstrated through simulations and experiments on a grid tied application.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.647-650
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• 2005

The paper aims on an analysis for dc boost control using Z-source inverter. The modified space vector PWM method is used for controlling both the dc boost and ac output controls in the Z-source inverter. The capacitor voltage and the voltage stress of device with both the shoot-through time and modulation index are analyzed considering the zero state time of inverter. The theoretical analysis is verified with the simulation studies and experiments with 32-bit DSP.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.638-642
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• 2005

This paper proposes a modified space-vector pulse width modulation (PWM) strategy which can restrict the common-mode voltage for three-phase to three-phase matrix converter and still keep sinusoidal input and output waveforms and unity power factor at the input side. The proposed control method has been developed based on contributing the appropriate space vectors instead of using zero space vectors. The advantages of this proposed method is to reduce the peak value of common-mode voltage to 42% beside the lower high harmonic components as compared to the conventional SVM method. Hence, the new table is also presented with the new space vector rearrangement. Furthermore, the voltage transfer ratio is unaffected by the proposed method. A simulation of the overall system has been carried out to validate the advantages of the proposed method.

• Journal of Power Electronics
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• v.10 no.3
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• pp.285-292
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• 2010

This paper presents a current mode integrated control technique (CM-ICT) using a modified voltage space vector modulation (MSVM) for Z-source inverter (ZSI) fed induction motor drives. MSVM provides a better DC voltage boost in the dc-link, a wide range of AC output voltage controllability and a better line harmonic profile. In a voltage mode ICT (VM-ICT), the outer voltage feedback loop alone is designed and it enforces the desired line voltage to the motor drive. An integrated control technique (ICT), with an inner current feedback loop is proposed in this paper for the purpose of line current limiting and soft operation of the drive. The current command generated by the PI controller and limiter in the outer voltage feedback loop, is compared with the actual line current, and the error is processed through the PI controller and a limiter. This limiter ensures that, the voltage control signal to the Z-source inverter is constrained to a safe level. The rise and fall of the control signal voltage are made to be gradual, so as to protect the induction motor drive and the Z-source inverter from transients. The single stage controller arrangement of the proposed CM-ICT offers easier compensation. Analysis, Matlab/Simulink simulations, and experimental results have been presented to validate the proposed technique.

• Journal of Power Electronics
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• v.17 no.4
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• pp.923-932
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• 2017

This paper proposes a novel scheme which can compensate the common-mode voltage (CMV) for five-level active neutralpoint clamped (5L-ANPC) inverters, which is based on modifying the space vector pulse width modulation (SVPWM) and adding an auxiliary leg to the inverter. For the modified SVPWM, only the 55 voltage vectors producing low CMV values among the 125 possible voltage vectors are utilized, which varies over the three voltage levels of $-V_{dc}/12$, 0 V, and $V_{dc}/12$. In addition, the compensating voltage, which is injected into the 5L-ANPC inverter system to cancel the remaining CVM through a common-mode transformer (CMT) is generated by the additional NPC leg. By the proposed method, the CMV of the inverter is fully eliminated, while the utilization of the DC-link voltage is not decreased at all. Furthermore, all of the DC-link and flying capacitor voltages of the inverter are well controlled. Simulation and experimental results have verified the validity of the proposed scheme.

• Journal of Industrial Technology
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• v.20 no.B
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• pp.147-154
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• 2000

This paper proposes an overmodulation strategy for space-vector PWM(SVPWM). The overmodulation strategy increases a fundamental output voltage and improves a voltage utilization up to the maximum in the overmodulation region. To maintain a linearity of the relation between a reference voltage and a fundamental output voltage, this paper suggests a compensation voltage, whose magnitude or phase is modified to the proposed control scheme. The practical implementation is simple and it is applied to improve an output voltage of SVPWM controlled AC Motor in the steady-state. The characteristic of the proposed strategy is confirmed by simulations and experiments for a V/F control of a induction motor.

• Journal of Power Electronics
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• v.18 no.4
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• pp.1027-1036
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• 2018

In this paper a new generalized space vector pulse width modulation scheme is proposed based on the principle of reverse mapping to drive the switches of multilevel inverters. This projected scheme is developed based on the middle vector of the subhexagon which holds the tip of the reference vector, which plays a major role in mapping the reference vector. A new approach is offered to produce middle vector of the subhexagon which holds tip of the reference vector in the multilevel space vector plane. By using middle vector of the subhexagon, reference vector is linked towards the inner two level sub-hexagon. Then switching vectors, switching sequence and dwell times corresponding to a particular sector of a two-level inverter are determined. After that, by using the two level stage findings, the switching vectors related to exact position of the reference vector are directly generated based on principle of the reverse mapping approach and do not need to be found at n level stage. In the reverse mapping principle, the middle vector of subhexagon is added to the formerly found two level switching vectors. The proposed generalized algorithm is efficient and it can be applied to an inverter of any level. In this paper, the proposed scheme is explained for a five-level inverter and the performance is analyzed for five level and three level inverters through MATLAB. The simulation results are validated by implementing the propose scheme on a V/f controlled three-level inverter fed induction motor using dSPACE control desk.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.10-13
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• 1998

In this paper, a control strategy of the three phase ZVT inverter for ac motor drives is proposed. The topology of ZVT inverter analyzed with a description of the control conditions dependent on the load current and MSVM(Modified Space Vector Modulation). The detailed simulation results indicate that zero-voltage operation during transition of the MSVM algorithm can be achieved.