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A muti resonant controller for high-frequency-link single-phase inverter is proposed in this paper. An equivalent circuit, which behave just like conventional unipolar PWM inverter is proposed for the converter. The dynamic model of the inverter, which built in continuous domain, is built. The inverter has the advantages of high efficiency, high power density, low-cost, low noise, bidirectional power...
The aim of this paper is to explain a novel technique to improve voltage and frequency profiles on microgrids controlled using the droop control scheme. The method consists on retuning the controller according to the present load scenario by adjusting the droop coefficients in a way that is proportional to the load changes. The proposed technique is tested through numerical simulations and the results...
This paper presents a control strategy for a flexible single-phase microgrid that can operate in grid-connected or in islanded mode. The microgrid adopted is composed of two voltage source inverters (VSIs) operated in parallel and two local nonlinear loads. This approach is based on a hierarchical structure which consists of inner, primary and secondary levels. The inner control regulates the output...
Repetitive control (RC) scheme presents an attractive solution to achieve excellent steady-state tracking error and low total harmonic distortion (THD) for periodic signals. RC can produce extremely large gains at fundamental and each harmonic frequency of reference signal to achieve all harmonics suppression. However, a DC-AC inverter always has uneven THD distribution, e.g. THD concentrates at 4fc...
This manuscript presents modified scheme of synchronous space-vector modulation allowing providing nonlinear dependences between the fundamental voltage and fundamental frequency of dual three-phase open-winding ac drive with four modulated inverters. Behavior of the system with six control modes (characterized by different dc-voltages and switching frequencies of inverters) and two nonlinear Voltage/Frequency...
Materials of this paper show possibility of realization of any nonlinear dependences between voltage and frequency (nonlinear V/F (Volt/Hertz) dependences) of the open-loop six-phase drive on the base of four inverters, controlled by specialized algorithms of space-vector modulation. Specific continuous and discontinuous schemes of modulation allow providing in this case symmetry of the phase voltage...
In this paper the asymmetrical pulse width modulation (APWM) is proposed for the control of galvanically isolated impedance-source series resonant DC/DC converters in the buck mode. Contrary to the variable frequency control, which is most widespread control technique of the series resonant converters, the APWM features fixed frequency operation and reduced circulation energy of the converter. This...
A controller is proposed for a medium voltage medium frequency (MVMF) AC collection grid for utility scale Photovoltaic (PV) farms. A new MVMF AC collection grid was presented in previous work. It enhanced the system modularity, increased the system efficiency and reduced the passive component sizes. The MVMF AC collection grid comprises modules of inverter and medium frequency transformer that are...
For constant voltage constant frequency pulse-width modulation (PWM) inverter system, repetitive control (RC) can achieve zero steady-state tracking error for any periodic signal. Multi-rate repetitive control (MRC), which is featured by a fast system sampling rate and a reduced RC rate, is able to lower CPU computation load while achieving low tracking error and fast convergence speed. To accurately...
Energy technologies have a central role in social and economic development at all scales, from household and community to regional, national, and international. Among its welfare effects, energy is closely linked to environmental pollution and degradation, economic development, and quality of living. In this paper, we will give a look at important of distributed generation as an approach in integration...
This paper presents a new controller of a microgrid connected converter to reduce harmonic components to ensure high quality of electrical power, although the microgrid connected inverter with an LCL filter has the ability of attenuating the higher order harmonics. The major advantage of the proposed controller is that it can attenuate both the higher and lower order harmonics with a small size line...
The requirements of generating various low frequency voltage waveshapes are usually catered by using linear amplifiers, which results in low overall efficiency. High frequency voltage source inverters with low pass filter at the output are not suitable for these applications, as it is difficult to produce waveshapes containing high frequency components, and variation in frequency. A Boost Inverter...
Ripple current at twice the output frequency exists at dc side in single phase inverter due to the instantaneous power imbalance between input and output power. Neutral-point voltage waveform control method is proposed in this paper to eliminate the ripple current in E-capless full-bridge inverter. With the proposed method, the pulsation power is controlled to only flow through ac capacitors and the...
This paper presents a new photovoltaic (PV) micro-inverter topology. The topology is based on a partial power processing resonant front end dc-dc stage, followed by an interleaved inverter stage. The input stage provides high efficiency, and flexibility of design for wide input voltage range and the output stage provides an effective switching ripple of twice the PWM frequency, which reduces the output...
This paper proposes an Internal Model Principle (IMP) based Selective Harmonic Controller (SHC) for power converters. The proposed SHC offers an optimal control solution for power converters to mitigate power harmonics. It makes a good trade-off among cost, complexity and performance. It has high accuracy and fast transient response, and it is cost-effective, easy for real-time implementation, and...
Variable carrier frequency control of PWM inverter based on deadbeat control using SoC-FPGA based hardware controller was proposed. To adopt to the fault ride through (FRT) conditions, deadbeat control was introduced to control the output current, and variable carrier method was applied to achieve high efficiency without the deterioration of controllability of the output current. The disturbance compensator...
In distributed generation(DG)unions, the requirements of inverter could be operated in island mode as a voltage source, which could also be operated in grid-tied mode as a current source. When the inverter transfer between the two modes, which may arouse spike of the voltage and current. This paper analyzed the features of inverter in voltage control mode and current control mode, respectively, and...
This paper is to present a new model of Voltage and frequency drive control for inverter fed Induction motors. The V/f drive control is based on buck/boost converter circuit by changing the duration time and frequency. The output voltage and frequency of the inverter can control the speed of an induction motor. This new topology offers almost step up and step down of the output voltage without the...
This paper proposes a pulse-width-amplitude-modulation (PWAM) method for a boost-converter-inverter system in electrical vehicle motor drive application. A 1kW prototype has been built and tested. By using this method, a 87% switching loss reduction, a two times power density increase, and 30% cost reduction can be achieved. It is also demonstrated that it posses less harmonic distortion than SPWM...
A two-stage high-frequency link inverter with active clamper, which has galvanic isolation, two-stage power conversion, bidirectional power flow, high efficiency, and high power density, is investigated in this paper. Modulation method and control strategy are developed for this inverter to achieve satisfactory system performance. Experiments are carried out to evaluate the proposed modulation and...
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