Current-Mode Control with Asynchronous Sigma-Delta Modulation for Single-Phase Grid-Connected Inverters
Date Issued
2014
Date
2014
Author(s)
Chang, Chia-Hsi
Abstract
The objective of this dissertation is to develop two novel hysteresis-based current control strategies for single-phase grid-connected inverters (GCIs). One of the proposed current control strategies adopts the asynchronous sigma-delta modulation (ASDM), which consists of an integrator and a hysteresis comparator, to generate the gating signals for the power switches of the GCI. The usage of ASDM for the GCI’s output current control is first reporting in this dissertation. Since the ASDM has the variable switching frequency feature, it can improve the dynamic response and reduce the electromagnetic interference noise. Of particular importance, its switching frequency variation is much less sensitive to the power-stage parameters comparing to the conventional hysteresis current control. The other proposed current control strategy is to develop the constant-frequency ASDM (CF-ASDM) for the GCI’s output current control, which maintains the advantage of quick dynamic response. The operation principle and mathematic derivations of the proposed current-mode ASDM and CF-ASDM control strategies are developed thoroughly. A 1 kW GCI prototype for either ac or dc microgrid applications is built and tested. Computer simulations and experimental results are presented to confirm the theoretical results.
Subjects
遲滯型電流控制
非同步和差調變
變頻切換/定頻切換
市電併聯換流器
交流/直流微型電網
Type
thesis
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