Voltage sags are normally described by magnitude variation and duration. In addition to these quantities, sags are also characterized by unbalance (asymmetry), nonsinusoidal waveshapes, and phase angle shift (phase jump). These factors are important for determining the behavior of ac motor drives during sags. Voltage unbalance and phase angle shifts cause large unbalanced source currents to, ex...

In this paper, a buck half-bridge DC-DC converter is used as a single-stage power factor correction (PFC) converter for feeding a voltage source inverter (VSI) based permanent magnet brushless DC motor (PMBLDCM) drive. The front end of this PFC converter is a diode bridge rectifier (DBR) fed from single-phase AC mains. The PMBLDCM is used to drive a compressor load of an air conditioner through...

In this paper three-phase isolated source and non-isolated source cascaded two level inverter (CTLI) topology is used for grid connected photovoltaic (PV) system. The CTLI is one of the widespread topology in multilevel inverter. In this work, both topology isolated source and non-isolated source CTLI system are operated to supply active power with available solar irradiance and to supply react...

This paper presents the dc-link capacitor balancing control scheme and effective current regulation algorithms for the modular cascaded converters (MCCs). The analytical model for the dc-link voltage balancing and capacitor energy mechanism are presented. Based on the devised control models, an effective control method is devised for the dc-link capacitor voltages, i.e., the sum capacitor volta...

This paper proposes an output current ripple reduction algorithm using a proportional-integral (PI) controller for an energy storage system (ESS). In single-phase systems, the DC/AC inverter has a second-order harmonic at twice the grid frequency of a DC-link voltage caused by pulsation of the DC-link voltage. The output current of a DC/DC converter has a ripple component because of the ripple ...

This paper presents the modeling, rapid control prototyping, and hardware-in-the-loop testing for real-time simulation and control of a grid-connected doubly fed induction generator (DFIG) in a laboratory-size wind turbine emulator for wind energy conversion systems. The generator is modeled using the direct-quadrature rotating reference frame circuit along with the aligned stator flux, and the...

This paper presents first an overview of the wellknown voltage and current dc-link converter topologies used to implement a three-phase PWM ac–ac converter system. Starting from the voltage source inverter and the current source rectifier, the basics of space vector modulation are summarized. Based on that, the topology of the indirect matrix converter (IMC) and its modulation are gradually dev...

High-voltage and power capability of multilevel converters better used for unified power-flow controller (UPFC application). The three-level neutral-point-clamped (NPC) converter allows back-to-back connection as the UPFC shunt and series converters than other multilevel topologies. In place of the pulse width-modulated (PWM) multilevel control schemes, constant dc-link voltage and balanced vol...

A method of actively maintaining voltage margin in field oriented induction machine controllers is proposed. A voltage margin controller is developed that rejects dc link and load disturbances such that current regulation and field orientation is maintained. In addition, the voltage margin controller coupled with rotor flux oriented control is shown to provide maximum torque capability equivale...