This paper presents a new bridgeless switching converter which is used as an electrical vehicle charger. It connects directly to the utility plug and its output DC voltage varies in the range of 350 ...V to 650 V. We employ the borderline or peak current control here to correct the charging power factor. This control technique produces lower high-frequency conduction noise rather than other similar techniques, which guarantees the electro-magnetic compatibility (EMC). A clamp capacitor connected in series with source utility brings a DC voltage shift at input nodes, thus converter input voltage remains always positive and there is no need to any active or passive bridge. Averaged instant value of the converter input current is sinusoidal and is in phase with the source voltage. Also, this converter can draw the sinusoidal current at any phase difference with the input AC source. In the other word, the proposed charger is capable of bi-directional power delivery that is an important feature especially in the intelligent charging applications. This charger is a member of synchronous boost family, also it has lower components count and then lower production cost. Finally, the proposed converter and control technique are simulated and validated using Power Simulator (PSim6) software. Very good agreements between the theoretical and simulation results are achieved.
Phase-shifted carrier (PSC) pulsewidth modulation (PWM) in its conventional form is a good solution for single-phase Cascaded inverters as alternative phase opposition disposition (APOD) PWM for ...single-phase diode clamped inverters. PSC distributes the switching angles of APOD PWM waveform among the legs uniformly and reduces the switching frequency of each leg. This paper proposes a modified PSC technique based on partly shifted carriers for all disposition types including phase disposition (PD) which is suitable for three-phase cascaded inverters. Simulation results are also included for using carrier-based space-vector PWM (SVPWM).
In this paper, a flux search controller is proposed to improve the efficiency of direct torque control of a six-phase induction machine. The proposed flux search controller is based on adaptive ...gradient descent of motor flux value with fast response and easy implementation. A proper loss model of six-phase induction motor in conjunction with the proposed method has been presented. Stator frequency variation with respect to flux reduction is considered as a new aspect of fast flux search control. Reduction of the flux in the search control technique leads to an increase in stator frequency, and an error in core loss calculation occurs if the frequency variation is ignored. The proposed search controller greatly improves efficiency by reducing core loss as well as harmonics loss. The approach not only is easy to implement and adaptive with regard to parameter variations but also requires no additional hardware for practical implementation. The simulation and experimental results presented in this paper verify the effectiveness of the proposed method in improving efficiency of direct torque control of six-phase induction motor drive.
This letter presents an inverse class-F power amplifier (PA) where the second-harmonic voltage produced by the nonlinear gate-source capacitor (<inline-formula> <tex-math ...notation="LaTeX">C_\text{GS}</tex-math> </inline-formula>) of the gallium nitride (GaN) HEMT transistor improves the PAE and output power. The design is based on multiharmonic recursive source-pull (SP) and load-pull (LP) simulations to determine the optimum design space. With proper impedance terminations at <inline-formula> <tex-math notation="LaTeX">f_\text{0}</tex-math> </inline-formula> and <inline-formula> <tex-math notation="LaTeX">\text{2}f_\text{0}</tex-math> </inline-formula>, the second-harmonic input voltage improves the PAE by about 10%. An X -band proof-of-concept PA is implemented in a 250-nm GaN technology with a <inline-formula> <tex-math notation="LaTeX">f_\text{max}</tex-math> </inline-formula> of 50 GHz. At 9.5-GHz center frequency, 17.8 W peak output power and 43<inline-formula> <tex-math notation="LaTeX">\%</tex-math> </inline-formula> power added efficiency are achieved for pulsed-mode operation with a pulse repetition frequency of 10 kHz and a duty cycle of 10<inline-formula> <tex-math notation="LaTeX">\%</tex-math> </inline-formula>. The designed three-stage PA consumes 7.72 mm<inline-formula> <tex-math notation="LaTeX">^\text{2}</tex-math> </inline-formula> die area and dissipates about 39 W dc power at saturation.
In this paper, a high linear, low-voltage two-quadrant current squarer as multifunction analog cell, is presented. To implement the squarer circuit, translinear loops with matched NMOS transistors ...operating in weak inversion region are used. The proposed cell is used as a basic building block for current-mode computational analog functions such as rectifier (absolute-value), multi-input vector summation and exponential function generator. We perform post-layout plus Monte Carlo simulations of the presented functions with 0.18 μm (level-49 parameters) TSMC CMOS technology that prove their superiority over some other advanced works and robustness against PVT (process, voltage and temperature) variations.
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•Using a cell for realization of current-mode computational analog functions.•Using translinear loops with matched NMOS transistors operating in weak inversion region for the proposed cell realization.•Implementation of rectifier (absolute-value), multi-input vector summation and exponential function generator by the proposed cell.•Ultra-low-power dissipation, low supply voltage, low non-linearity as well as distortion, are main advantages of the proposed analog designs.
This paper presents a new bridgeless switching converter which is used as an electrical vehicle charger. It connects directly to the utility plug and its output DC voltage varies in the range of 350 ...V to 650 V. We employ the borderline or peak current control here to correct the charging power factor. This control technique produces lower high-frequency conduction noise rather than other similar techniques, which guarantees the electro-magnetic compatibility (EMC). A clamp capacitor connected in series with source utility brings a DC voltage shift at input nodes, thus converter input voltage remains always positive and there is no need to any active or passive bridge. Averaged instant value of the converter input current is sinusoidal and is in phase with the source voltage. Also, this converter can draw the sinusoidal current at any phase difference with the input AC source. In the other word, the proposed charger is capable of bi-directional power delivery that is an important feature especially in the intelligent charging applications. This charger is a member of synchronous boost family, also it has lower components count and then lower production cost. Finally, the proposed converter and control technique are simulated and validated using Power Simulator (PSim6) software. Very good agreements between the theoretical and simulation results are achieved.
Natural capacitor voltage balancing for Flying Capacitor and Stacked Multicell converters require uniform distribution of switching transitions among cells. The state-machine-decoder has been known ...as the optimal technique to achieve this goal. In this paper, however, it is shown that the conventional state-machine-decoder may not generate the optimal balancing scheme for Stacked Multicell converters. The reason behind the suboptimal distribution is investigated and a correction to the state-machine-decoder is proposed to achieve the optimal distribution. Simulation results are included to support the proposed correction.
The proposed PWM switch modelling technique is a simple method for modelling push-pull based single phase inverters operating in continuous conduction mode. In the design process of converters it is ...desirable to assess as many critical design parameters and parasitic effects by simulation as possible, since the control is hard to tune after fabrication. The main advantage of this method is its versatility and simple implementation. Furthermore, the introduced model also includes parasitic elements of the components to better estimate the converter behaviour. The resulting circuit is a time averaged model where all currents and voltages correspond to their averaged values. The validity of this model is verified by the given experimental results for a specified design example. This modelling technique helps to design the inverter effectively and better choosing the controller component values to achieve a good dynamic response. Finally, current mode controlled push-pull converter is simulated and compared with proposed modelling technique where a good accordance between them is revealed. Simulation analysis is done by Matlab 9 and Psim 6 software. The overall modelling estimation error was lower than 5 %.
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