Closed loop selective harmonic elimination applied to a grid connected PWM converter with LCL filter

Abstract

This paper presents the development and design of a control strategy applied to a three-phase grid connected PWM converter with Selective Harmonic Elimination (SHE). First, the transcendental equations of SHE are solved offline and then stored in a look-up table inside of the SHE-Modulator, which is implemented using a FPGA. Synchronism with the grid is obtained using a modified Digital PLL which includes the Modulator with SHE. A discrete model is obtained in dq synchronous frame for the converter with LCL-filter with passive damping and dq PI controllers are used to provide zero steady-state error of grid current. Finally, simulation results are presented to validate the proposed approach.

Dynamic and Steady State Response Analysis of Selective Harmonic Elimination in High Power Inverters

“…In other researches, the implementation of SHE is generally achieved by a microcontroller unit (MCU) and a field programmable gate array (FPGA), where MCU is responsible for sampling and control procedures, and FPGA is responsible for SHE modulation [10], [42]. A large scale of FPGA is usually needed as the number of the switching angle increases because a large amount of switching angle data and control information need to be transmitted between MCU and FPGA.…”

“…Selective harmonic elimination (SHE) was first proposed in the early 1960s, and quickly developed into the form of the current version [8], [9]. Since its proposal, SHE has been found to stand out among the modulation strategies because of the reduced number of commutations and tight control of low order harmonics [10]. The engineering application of SHE was limited at the beginning because of the huge difficulties of solving the nonlinear and transcendental equa-tions [11].…”

Model predictive control approach for frequency and voltage control of standalone micro‐grid

“…PWM generator of EI‐DG should be equipped with selective harmonic elimination (SHE) module that consists of offline calculations of converter switching angles stored in a look‐up table to eliminate the undesirable harmonics for different modulation indexes [24]. Higher order harmonics that are not eliminated by SHE module can be attenuated using passive LC filter of EI‐DG.…”

FPGA-Based Space Vector PWM and Closed Loop Controllers Design for the Z Source Inverter

“…Owing to this reason, FPGA based palatforms have been broadly used for accelerating many systems. The unwanted voltage and current fluctuations that can be seen in the output can be minimized by reducing the delay between the output and the controller by using FPGA [15]. Apart from PWM and closed loop control, the determination of the circuit parameters of the ZSI is very important for the reliability of the drive circuit.…”