Effective and Simple Control of Grid-Connected Three-Phase Converter Operating at a Strongly Distorted Voltage

Abstract

Three-phase power electronics converters (PECs) are commonly used as an interconnection of DC loads/sources with the electrical AC power system. Their important goal is to ensure three-phase symmetrical and pure sinusoidal grid current waveforms. Unfortunately, frequent adverse of grid voltage conditions like the occurrence of higher order harmonics and dips/sags leads to problems in maintaining high-quality parameters of current and stable operation of PEC. Therefore, a more complex control algorithms are usually used to solve those problems. In this paper, effective and simple control is proposed to mitigate grid current distortions caused by grid-voltage harmonics. This improvement of current quality can be easily obtained in control of grid-connected PEC using only band notch filtered grid voltage as a feedforward without any additional control loops parallel connected to linear current controllers (tuned to fundamental frequency). Theoretical analysis with simulation and experimental investigations are presented, which prove very good properties and advantages of the proposed control idea. INDEX TERMS Current harmonics mitigation, DC-AC power conversion, grid distortions, harmonic distortion, voltage control.

A current sensorless control method for multi‐level active front‐end rectifiers with LCL filter

“…As mentioned in the Introduction, existing control methods developed for three-phase rectifiers with LCL filters utilize the capacitor voltage and/or inductor current feedbacks [11][12][13][14][15][16][17][18][19][20][21]. It is worth noting that the measurements of grid voltages in all of these control methods are essential for synchronization purposes.…”

“…As a remedy to this problem, the LCL filters which offer better attenuation than L filters are considered an effective solution in grid-connected rectifiers [11][12][13][14][15][16][17][18][19][20]. However, the use of an LCL filter increases the control complexity.…”

“…On the other hand, with the aim of achieving control objectives such as unity power factor operation, fast dynamic response to sudden load and reference variations, and low total harmonic distortion (THD) in the grid currents, various control methods are developed for three-phase rectifiers with LCL filter. These methods require grid current measurement [11], rectifier current measurement [12][13][14][15], grid current and rectifier current measurements [16], rectifier current, capacitor current and capacitor voltage measurements [17], rectifier current and capacitor voltage measurements [18,19], and grid current and capacitor current measurements [20,21]. An insight into the complexity of these control methods can be obtained by counting the number of required measurements.…”

“…An insight into the complexity of these control methods can be obtained by counting the number of required measurements. Hence, based on the control methods in [12][13][14][15][16][17][18][19][20][21], the number of required sensors (including the grid voltage measurements) varies from six to twelve. When the number of sensors is increased, the cost and power losses arising because of the measurements also increase and the reliability of the system is adversely affected due to the increased risk of sensor faults.…”

Smart actuator for IM speed control with F28335 DSP application

“…There are two techniques of control used: hysteresis and proportional integral (PI) [25]. To improve the wrong compensation, the side of DC is collected from sources of: 1) current, 2) controlled current linked with static load, and 3) controlled voltage obtained because of its rapid dynamic response [26]. The traditional algorithm of DTC relies on the immediate values and is directly computed using the digital control signals for the inverter [27].…”