A Dual Two-Level Inverter Scheme With Common Mode Voltage Elimination for an Induction Motor Drive

Abstract

Pulse-width modulated (PWM) inverters are known to generate common mode voltages which cause motor bearing currents in the induction motor drives. They also result in leakage currents which act as sources of conducted electromagnetic interference in the drive system. The common mode voltage generated by a conventional three-level inverter can be eliminated by switching only the voltage space vectors which do not produce the common mode voltage. This paper presents a PWM switching strategy to eliminate common mode voltage using the open-end winding configuration for the induction motor. The switching strategy presented in this paper, does not generate any alternating common mode voltages in the drive system and hence the electrostatic coupling of the common mode voltage, which results in the bearing currents and the leakage currents, is avoided. The proposed scheme is devoid of neutral point voltage fluctuations and does not require neutral point clamping diodes, when compared to the common mode elimination scheme based on the conventional three-level inverter topology. Also, the present scheme uses a single dc-link with half the voltage compared to the conventional three-level inverter based scheme. Index Terms-Common mode voltage, open-end winding induction motor drive. NOMENCLATURE The dc-link voltage of the neutral point clamped three-level inverter. The pole voltages of INV1. The pole voltages of INV2. The voltage across the phase windings of the induction machine. The combined voltage space phasor for , and. The combined reference voltage space phasor for the dual inverter. The individual reference voltage space phasor for inverter-1 (INV1). The components of along theaxes. The components of along theaxes. The angle of the combined reference space phasor with the A-phase axis.

New Research on AC–AC Converters without Intermediate Storage and Their Applications in Power‐Electronic Transformers and AC Drives

“…The rectified voltage is acts as three-level voltage for the three-level inverter. The three-level inverter is operated as a two-level inverter in order to eliminate any common-mode voltage in the machine [14]. The switching in the inverter and rectifier and matrix converter are synchronized in order to eliminate any change in voltage levels at the primary of transformer [28].…”

“…The open-ended three-phase drive systems are obtained by opening the stator winding neutral of the three-phase motor and driving the motor from both sides of the stator winding using two inverters [12][13][14][15]. By doing so, the output voltage is enhanced and the DC-link voltage requirement is reduced.…”

Reduction of Common Mode Voltage in Asymmetrical Dual Inverter Configuration Using Discontinuous Modulating Signal Based PWM Technique

“…However, these methods cannot reduce the CMV variations. Therefore, [25] presented a modified circuit topology for symmetrical dual inverter configuration. Nonetheless, this topology eliminates CMV with output voltage of poor quality.…”

A Space Vector PWM With Common-Mode Voltage Elimination for Open-End Winding Five-Phase Drives With a Single DC Supply

“…The approach in [9] uses space vectors which do not generate the CMV. Therefore, theoretically, every modulation technique that utilizes only these space vectors would result in zero CMV.…”