Fuzzy PWM based on Genetic Algorithm for battery charging

Dual two-level inverter can synthesize three-level output voltage. Carrier phase-shifted sinusoidal pulse width modulation (SPWM) is proposed in this paper by exploiting the idea of using both phase shifted modulating signals and also phase shifted carrier signals for the dual two-level inverter. The proposed pulse width modulation (PWM) method is aimed at reducing the common mode voltage (CMV) generated by the dual two-level inverter. The implementation of the proposed PWM is simple as it involves a simple comparison of modulating and carrier signal. A significant reduction in the peak to peak value of the CMV is achieved which is as high as 66.66% with the use of the proposed PWM compared to existing SPWM. The proposed carrier based PWM is first simulated using MATLAB/Simulink and experimentally validated using a laboratory prototype of a dual two-level inverter feeding a 3-φ open-end winding induction motor drive.

This paper proposes the pulse width modulation (PWM) control strategy for low-speed operation in the three-level neutral-point-clamped (NPC) inverters based on the bootstrap gate drive circuit. For the purpose of the cost reduction, several papers have paid attention to the bootstrap circuit applied to the three-level NPC inverter. However, the bootstrap gate driver IC cannot generate the gate signal to the IGBT for low-speed operation, because the bootstrap capacitor voltage decreases under the threshold level. To solve this problem, the dipolar and partial-dipolar modulation can be the effective solution. Nevertheless, these modulation have drawbacks in terms of the switching loss and THD. Therefore, this paper proposes the PWM control strategy to operate the inverter at low-speed and to minimize the switching loss and harmonics. The experimental results are presented to verify the validity on the proposed method.

This paper proposes a new modulation technique that can reduce the current distortion and extend the current reconstruction range for a three-phase inverter using only dc-link sensor. The proposed pulsewidth modulation (PWM) technique is a hybrid method which consists of space vector modulation method and the PWM method without using null switching states. The former provides low current distortion; however, it is with narrower current reconstruction range. In contrast, the latter extends the current reconstruction range at the cost of higher current distortion. For the proposed method, in the measurable region of space vector modulation method, space vector modulation is used to reduce the current distortion. Moreover, as the modulation range is out of the measurable region, the PWM method without using null switching states is applied to extend the current reconstruction range. Furthermore, the current reconstruction limitation using only dc-link sensor is analyzed. The analysis shows that the reduction of PWM switching frequency and acquisition time can extend the current reconstruction range. Comparison of experimental results derived from a field-programmable gate array-based controlled inverter is included. It will be demonstrated that using the proposed hybrid PWM technique, the three-phase current signals of the inverter can be reconstructed even under very low modulation index range while providing low current harmonic distortion of inverter output.

In this thesis, a boost chopper using PV (Photovoltaics) system and PWM (Pulse Width Modulation) voltage type power converter were constructed to provide a pleasant environment to the patients in the hospital wards by controlling temperature, humidity and air-conditioning & heating. For the stable modulation of solar cell, synchronizing signal and control signal were processed using one chip microprocessor. Power converter system was constructed with booster chopper and voltage source inverter and test was carried out for both devices. Constant voltage control method was used to track a maximum power point at boost converter control. For the inverter control, synchronizing signal and control signal were processed by microprocessor for the stable modulation according to the switching theory of SPWM (Sinusoidal Pulse Width Modulation) and directions to each sector. Test was carried out for inverter control using SPWM control method. In addition, grid voltage was detected and this grid voltage and inverter output were operated at the same phase for the phase locking with PWM voltage source inverter so that surplus power could be linked to grid. This characteristic was applied on the temperature and humidity sensors in the general buildings and buildings having specific purposes such as hospitals. The good dynamic characteristic of inverter could be obtained by these applications. Also, PWM voltage inverter maintains a high power factor and low-frequency harmonic output so that power can be supplied in the load as well as system.

This paper presents new gating techniques to improve the efficiency of full-bridge DC-DC converter for battery charging in electric vehicles. The converter is assisted by a passive auxiliary circuit to extend the soft-switching range. The uncontrolled auxiliary circuit current increases the conduction losses of the converter when gated with conventional phase-shift modulation (PSM) technique. The controlled auxiliary circuit current with the proposed pulse-width modulation (PWM) gating techniques increases the efficiency of the converter compared to PSM especially at light-load conditions under constant voltage charging mode. In this paper, the steady-state analysis of the DC-DC converter auxiliary circuit with the PWM gating techniques is presented. A comparative loss analysis with PWM and PSM gating techniques is also given. A 1.2-kW, 100-kHz converter is implemented on ORCAD-Pspice and the simulation results are given to validate the improvement in efficiency of the converter with the proposed PWM gating techniques.

Smart rheological materials represented by giant electrorheological fluid (GERF) have attracted considerable attention in vibration isolation, microfluidics, and robotics. The traditional control method is primarily to adjust the amplitude of the constant voltage. This paper introduces a GERF damper that works in squeeze mode and uses varying pulse width modulation (PWM) voltage for damping adjustment. The influence of PWM voltage parameters on the damping characteristics of the damper is analyzed through experiments. The similarities and differences between the constant voltage and PWM voltage are discussed. PWM voltage can obtain larger equivalent damping with small duty cycles. A parametric model is established based on the squeeze flow principle to describe the damping characteristics of the damper. The root mean square error between the experimental and model results is less than 0.015, which verifies the accuracy of the model. The results of the vibration platform test show that the PWM voltage control can adjust the transmissibility of the damper in the frequency domain. The amplitude of the vibration is reduced by 56% in the time domain. This study provides a new damping adjustment method for GERF dampers.

The number of voltage levels available in pulsewidth modulation (PWM) voltage source inverters can be increased by using a split-wound coupled inductor within each inverter leg and interleaved PWM switching of the upper and lower switches. The magnetizing inductance of the symmetrical split-wound inductor filters the high-frequency PWM voltage differences between the upper and lower switches. The same inductor presents a three-level PWM voltage at the inverter output terminals, with the winding leakage inductance being located in series with the low-frequency output current. Deadtime PWM signal delays can be reduced as DC-rail short circuits are not possible: as a result, the quality and voltage range of the PWM output is improved. Since the inductor windings are technically exposed to high-frequency PWM AC voltages with no DC components, device voltage drops help to reduce the buildup of winding DC currents. Theoretical analysis and a sample design case are presented to illustrate how to design suitable inductors for the various topologies. Simulation and experimental results are used to illustrate the operation of the proposed inverter structures.

Purpose This paper aims to present a modified space vector pulse width modulation (SVPWM) technique for six-phase induction motor drive based on common-mode voltage (CMV) and current losses which are two important issues affecting drive system behavior and quality. Design/methodology/approach It is shown that the presence of z-component currents and the presence of CMV in six-phase drive system are two major limiting factors in space vector selection. The behavior of several space vector selections in a two-level inverter considering minimum CMV and z-components is investigated. Then, the space vectors in a three-level inverter is analyzed and tried to explore an SVM technique with better behavior. Findings The analyses show that all the problems cannot be solved in a six-phase drive system with two-level inverter despite having 64 space vectors; this study tried to overcome the limitations by exploring space vectors in a three-level inverter. Originality/value The proposed pulse width modulation (PWM) strategy leads to minimum current distortion and undesired current components with zero CMV and modest torque ripple.

In order to supply power from renewable energy source at a low dc voltage to a grid at a high ac voltage, small signal modeling, analysis and pulse width modulation (PWM) control of a novel switched quasi-Z-source boost inverter is presented in this paper. By adding a hybrid switched-inductor-capacitor structure to the traditional quasi-Z-source inverter (qZSI), the new topology generates high dc-ac voltage gain using a low shoot-through duty ratio and a large modulation index to improve the output voltage. The steady-state analysis and PWM control strategy have been discussed in this paper. Meanwhile, State-space averaging method is used to derive the small signal model. Based on the derived small signal and calculation of open-loop transfer function, the stability of the open-loop control is guaranteed. To achieve better performance, a closed-loop control scheme for the proposed topology is introduced. Simulation results are presented to validate the theoretical analysis and control strategy of the novel inverter.

The inverters and control methods are applied in more and more fields with power electronics development. The technology of current hysteretic band PWM is a kind of easy and reliable control method. But the harmonic distortion of load current is big amplitude around switching frequency side band. The paper introduce a Varied Hysteretic-band Current control technique(VHBCC), this method can spreads the spectrum contents of load current around switching frequency side band, reduces the harmonic distortion of load current . At last, The results of simulation prove the method feasible and effective.

This work proposes a methodology to estimate core losses under pulsewidth modulation (PWM) or dc bias ripple voltage excitations. A special hysteresisgraph was built to measure toroidal samples under pulsed voltages. An experimental methodology, based on the principles of ferromagnetism, was implemented to investigate minor loop losses in toroidal samples of oriented and nonoriented FeSi. Triangular induction waveforms with constant dB/dt were generated. The results demonstrated that minor loops produced by PWM voltage, do not affect the major hysteresis loop losses nor the losses of other minor loops measured at different points of the major loop. In these experiments, minor loop losses under PWM voltage were very similar to minor loop losses under dc bias ripple voltage. Aspects of the behavior of minor loop losses as a function of amplitude and magnetic flux density are reported in this work.

In this paper, a selective harmonic mitigation pulse width and amplitude modulation (SHM-PWAM) control strategy, for three-phase four-leg inverters has been proposed. In this way, the pulse amplitude modulation (PAM), which is mainly used in communication systems, is applied simultaneously with the pulse width modulation (PWM), to the three-phase four-leg inverter. Considering PAM increases the system degrees of freedom in mitigating harmonics compared with the conventional PWM strategy. The control signals of three legs voltage source inverter, mathematically expressed using Fourier-based equations to eliminate lower order nontriplen harmonics, and the fourth leg produces the harmonics that are equal to the lower order triplen harmonics which produced by the other legs. Simulation results show the performance of the SHM-PWAM strategy from the THD point of view, compared with SHM-PWM strategy.

The authors describe a control scheme incorporated in the voltage-fed full-bridge series resonant high-frequency inverter using static induction high power transistors (SITs), which is based on a load-adaptive variable frequency modulated phase-shift PWM (pulse-width modulation) control strategy. The operating principle of the load-adaptive variable frequency PWM series resonant inverter system with a new control scheme is described along with its operating characteristics in steady state. The 20 kW-200 kHz prototype inverter system suitable for induction heating in industry is demonstrated, including a specially designed power transformer. SIT stacks with a water cooling system, and a building-block assembly for high-power use. Experimental results and simulation results are presented. Finally, an improved variable frequency PWM series resonant inverter topology incorporating partially inserted capacitive lossless snubbers is proposed for soft switching and compared with the inverter mentioned above. >

End turn grading with resistive–capacitive coupling experiences severe electrothermal stress when subjected to pulse width modulation (PWM) voltage. In this paper, several experiments and simulations were carried conducted for four types of end turn grading. First of all, the temperature rise in the end turn grading increased with a decrease in rise time. When the rise time was less than 500 ns, the temperature rise at the terminal was higher owing to the increased capacitive current coupled from the main wall insulation. Further, the current in the linear region exhibited minimal variation at different fundamental frequencies resulting in synchronized the temperature rise at the terminal and overlap. Furthermore, the jump voltage was the key factor influencing temperature rise in end turn grading, confirmed by comparing different voltage magnitudes. Finally, the transient behaviour of the maximum field in the stress grading material was determined at rise time. The experimental and simulation results indicate that balancing and interdependently addressing the electrical and thermal stress protection in end turn grading is crucial. The study aims to provide an experimental and theoretical foundation for an insulation system of inverter‐fed rotating machinery operating under PWM voltage.

This paper proposes the simplified pulse width modulation (PWM) strategy in the bidirectional ac/dc single-phase converter with the feed-forward control scheme. In this, the number of switching of the proposed simplified PWM strategy is reduced to one-fourth to that of the unipolar & bipolar PWM. The feed-forward control scheme is used to achieve better performance of the ac/dc converter in both the rectifier & inverter mode as compared with the conventional dual-loop control scheme. The simplified PWM strategy with feed-forward control scheme has higher efficiency than that of the unipolar PWM & bipolar PWM strategies. Also, the total harmonic distortion is less in this PWM strategy. The simulation & experiments are carried out to verify the validity of the proposed PWM strategy & control scheme.