Multifunctional Grid-Connected Voltage Source Inverter to Drive Induction Motor Operating With High-Inertia Load

Abstract

This paper proposes a novel multifunctional topology for a grid-connected voltage source inverter to control the speed and power flow of a squirrel-cage induction motor. For high-inertia loads during startup, the issues faced include a large transient current and high heat generation. However, the solutions proposed by existing startup methods are inadequate. The topology presented in this study not only addresses the problems related to these methods, i.e., creating a smooth startup, but also presents a flexible alternative for power factor correction using capacitor banks. First, the proposed technique accelerates the motor smoothly to its operating point through the sinusoidal voltage provided by an inverter with an LC filter in its output. In the second step of the control method, after achieving stability in the desired operating point, a converter with an LC filter is assigned the task of power factor correction. Thus, the proposed topology achieves a smooth startup and unity power factor. It includes a new control strategy in which the rotor fieldoriented control method is employed for the speed control mode. Finally, the validity of the proposed theory is verified.INDEX TERMS field-oriented control, grid-connected inverter, induction motors, power factor correction, startup process. NOMENCLATURE Grid: uGrid voltage in the bus bar. v g , i gGrid voltage and current in coupling point. R g , L gGrid resistance and inductance. ω g , f gGrid frequency in rad/s and Hz. θ g Voltage phase measured in rad. Power converter with filter: v, i Filter output voltage and current. v i , i i Inverter output voltage and current. i c , i r Capacitance and damping resistance currents. R f , L f , C f Filter resistance, inductance, and capacitance. f r Resonance frequency. f s Switching frequency. V dc DC link voltage.

Systematic and Novel Approach to Modeling, Analysis and Control of Grid Tied PV Power Supply System Using Integral State Feedback Control and State Observer

“…From Fig. 11 the inverter system can be mathematically expressed in the synchronous reference frame as [29]:…”

Efficient Adaptive Regulation Strategy for Control Position of Induction Motors

“…In that scheme, an inverter with a capacitor is controlled to compensate for the increasing reactive voltage drop inside the motor as the speed increases. Paper [12] presents a proposal of a voltage source inverter to control the speed and power flow of a squirrel-cage induction motor. The features that they try to solve are to create a smooth startup, a stable control strategy, and a power factor correction using capacitor banks.…”