FRT capability of 100kHz single phase utility interactive inverter with FPGA based hardware controller

Abstract

In the near future, many distributed power systems will be connected to the utility line in the local area, the demand of the control accuracy to the utility interactive inverter will also become strict more than the present ability. The utility interactive inverter required FRT capability in the case of utility voltage fluctuation. Deadbeat control and PLL control with quasi dq transformation based on a 1MHz sampling were applied to the utility interactive inverter using FPGA based hardware controller. The FRT characteristics were verified through simulations and experiments. The superior characteristics of the proposed method was verified. The FPGA based hardware controller for the 100kHz career PWM inverter was designed and evaluated with experiments.

Current Harmonics From Single-Phase Grid-Connected Inverters—Examination and Suppression

“…Notably, those requirements tend to be even strengthened in the future, when the grid will become diverse and resilient. For instance, just like the case of wind power systems, the PV systems should be able to support the grid by means of injecting reactive current into the grid in the presence of a voltage drop [11], [12], [15], [22], [44]- [47]. Even in the normal operation mode, the grid voltage is not "constant" in terms of the amplitude.…”

Variable carrier frequency deadbeat control with hysteresis band using SoC-FPGA for utility interactive inverter

“…To adopt to the various grid condition of each connecting point of the inverter, authors proposed a singlerate deadbeat control with disturbance compensation method to achieve the robust control and very superior characteristics was obtained [6]. In the conventional deadbeat control method, the carrier frequency is fixed to design the control method because of the limitation of the ability of the control processors to derive the control gain in each carrier period.…”

Deadbeat Control with Disturbance Compensation Method and 1 MHz‐PLL for Single Phase Utility Interactive Inverter

“…In case of a threephase power system, instantaneous voltage phase and amplitude can be detected via coordinate transformation; however, in case single-phase system, voltage cannot be easily transformed to orthogonal coordinates. In this context, the authors proposed PLL control using quasi dq transformation [4,5], and combined it with deadbeat control in interactive utility inverters [7] to obtain good results [8][9][10][11]. On the other hand, higher sampling frequencies become possible with progress in A/D converters, thus promising improvement of control characteristics for instantaneous system response, which was difficult before.…”

“…On the other hand, higher sampling frequencies become possible with progress in A/D converters, thus promising improvement of control characteristics for instantaneous system response, which was difficult before. Thus, we implemented PLL control at 1-MHz sampling, and applied it together with disturbance compensation deadbeat control to an interactive utility inverter; in so doing, we explored the improvement of transient control characteristics during voltage sags [12]. Recently, FRT requirements were revised because of urgent concerns about system instabilities caused by simultaneous disconnection of multiple distributed generators because of system disturbances.…”