Improved Active and Reactive Control of a Small Wind Turbine System Connected to the Grid

This paper deals with the interconnection of a small wind turbine with the low voltage distribution grid and the implementation of an improved control scheme, which also serves educational purposes. Initially the subsystems—wind turbine, rectifying bridge, interleaved boost converter, three-phase inverter, interconnection inductors, lifting transformer, filtering capacitors—are investigated, in order to explain their selection, based on the LEMEC (Laboratory of Electromechanical Energy Conversion, Department of Electrical Engineering, UoP) educational policy. Afterwards, the three-phase inverter control scheme, which is responsible for controlling its input voltage (voltage of the DC Bus) and consequently the active power, as well as the reactive power injected into the grid (VQ control) is analyzed. This is accomplished through DQ transformation and PI controllers which are responsible for generating the appropriate reference signals, to generate the required Space Vector Pulse Width Modulation (SVPWM) pulses to drive the semiconductor switches of the inverter. In addition, it is explained how this particular control method can compensate reactive power in the grid, even in apnea, by automatically charging the DC Bus. Finally, simulation and experimental results are given to prove the proposed control method effectiveness.

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Modeling and control of a hybrid DC/DC/AC converter to transfer power under different power management strategies

International Journal of Power Electronics and Drive Systems (IJPEDS) ◽

10.11591/ijpeds.v12.i3.pp1620-1631 ◽

2021 ◽

Vol 12 (3) ◽

pp. 1620

Author(s):

Amin Alizadeh Asl ◽

Ramin Alizadeh Asl

Keyword(s):

Reactive Power ◽

Control Method ◽

Proper Time ◽

Management Strategies ◽

Additional Advantage ◽

Modeling And Control ◽

Phase Inverter ◽

Three Phase ◽

Three Phase Inverter ◽

Generation Power

<span>A hybrid DC/DC/AC converter connected to the grid without a three-phase transformer is controlled. The decentralized control method is applied to the hybrid DC-DC converter such that the maximum power of PV flows to the grid side. This controller must charge and discharge the battery at the proper time. It must also regulate DC-link voltage. An additional advantage of the proposed control is that the three-phase inverter does not need a separate controller such as PWM and SPWM. A simple technique is used for creating the desired phase shift in the three-phase inverter, which makes the active and reactive power of the inverter controllable. A new configuration is also proposed to transmit and manage the generation power of PV. In this<br />scheme, the battery and fuel cell are employed as an auxiliary source to manage the generation power of PV. Finally, a real-time simulation is performed to verify the effectiveness of the proposed controller and system by considering the real characteristics of PV and FC.</span>

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A Compensation Control Scheme of Voltage Unbalance Using a Combined Three-Phase Inverter in an Islanded Microgrid

Energies ◽

10.3390/en11092486 ◽

2018 ◽

Vol 11 (9) ◽

pp. 2486 ◽

Cited By ~ 8

Author(s):

Biying Ren ◽

Xiangdong Sun ◽

Shasha Chen ◽

Huan Liu

Keyword(s):

Control Method ◽

Voltage Drop ◽

System Control ◽

Droop Control ◽

Interface Circuit ◽

Phase Inverter ◽

Three Phase ◽

Control Scheme ◽

Islanded Microgrid ◽

Three Phase Inverter

A large number of single-phase loads in an islanded microgrid have a bad influence on the alternating current (AC) bus voltage symmetry, which will further impact the power supply for the other loads. In this paper, the combined three-phase inverter is adopted as the distributed generation (DG) interface circuit for its independent control of each bridge. However, the combined three-phase inverter will generate an asymmetrical voltage with the traditional droop control. Moreover, the system impedance also effects the voltage symmetry. Therefore, the improved droop control method based on the self-adjusting P-f and Q-U droop curves and the system impedance voltage drop compensation are proposed. The system control scheme is also designed in detail. A simulation and an experiment under the conditions of the balanced, unbalanced loads are carried out, and the results verify the feasibility and effectiveness of the control strategy.

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