Control of Variable Frequency Drive PWM to Mitigate Motor Overvoltage Due to Double Pulsing in Reflected Wave Phenomenon

Xiong, Han; Zhang, Julia

doi:10.1109/ecce.2018.8558140

Cited by 11 publications

(3 citation statements)

References 14 publications

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“…Further, under high switching frequencies, a greater than twice of the inverter voltage can occur at the motor terminal at high modulation indices. This is known as the double pulsing effect, where a second voltage pulse arrives at the motor terminals before the first reflected pulse is fully decayed under closely spaced PWM pulses [11] [14] [15], causing higher than double the inverter output voltage at the motor terminal.…”

Section: Introductionmentioning

confidence: 99%

Impact of High Switching Speed and High Switching Frequency of Wide-Bandgap Motor Drives on Electric Machines

Yuan

et al. 2021

IEEE Access

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The emergence of fast-switching wide-bandgap (GaN, SiC) power electronics devices has enabled motor drive systems to achieve high efficiency, power density, control bandwidth and high-level of integration. However, the fast-switching speed and high switching frequency result in an increased level of motor overvoltage at both motor terminals and stator neutral. This overvoltage increases the stress across the motor winding insulation and bearings. This paper investigates three types of motor overvoltages, i.e., differential mode (DM) (phase-to-phase) motor terminal overvoltage, common mode (CM) (phase-to-ground) motor terminal overvoltage and CM stator neutral overvoltage (motor neutral to ground). Both the high switching speed (high dv/dt) effect and the high switching frequency effect on the motor overvoltage are investigated in this paper, where the high switching frequency effect has not been fully addressed in existing literature. Significant overvoltage is observed when the switching frequency or its multiples coincide with the cable or motor anti-resonant frequency. The anti-resonant behavior in the cable and motor impedance has been used to identify the overvoltage oscillation frequency and to explain the overvoltage observations for the three types of motor overvoltages. The analysis has been tested using a 7.5kW motor setup with and without a four-core cable, driven by a SiC or a GaN three-phase inverter with a switching frequency up to 250kHz and switching speed up to 40kV/µs. In addition, the motor bearing current, which is a main cause of bearing degradation, has also been tested and the increase of bearing current is observed due to the high frequency effect.INDEX TERMS Anti-resonance, bearing currents, common-mode, differential mode, motor drive, motor overvoltage, neutral point voltage, gallium-nitride (GaN), silicon-carbide (SiC), switching frequency, switching speed, wide-bandgap.

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Section: Introductionmentioning

confidence: 99%

Impact of High Switching Speed and High Switching Frequency of Wide-Bandgap Motor Drives on Electric Machines

Yuan

et al. 2021

IEEE Access

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“…High voltage ratings and fast switching speeds of SiC devices can increase the voltage stress on the insulation of motor windings. First, the reflected wave phenomenon in a SiC device-based motor drive is more severe than that in a Si device-based system due to the fact that SiC devices can switch higher voltages at faster speeds [10] [11]. Second, fast-switched voltages create uneven voltage distributions in motor winding insulations [12] [13].…”

Section: Introductionmentioning

confidence: 99%

A Partial Discharge Study of Medium-Voltage Motor Winding Insulation Under Two-Level Voltage Pulses With High Dv/Dt

Wei

You

et al. 2021

IEEE Open J. Power Electron.

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Medium-voltage (e.g. 10 kV rated) silicon carbide (SiC) devices have great potentials in medium-voltage variable speed drives. But their high switching dv/dt can increase the voltage stress on motor windings and cause partial discharges. This paper presents a partial discharge study of a medium-voltage form-wound winding under two-level square-wave voltage pulses. A 10 kV SiC device-based test platform is built to generate voltage pulses with high dv/dt. A three-step test approach is proposed and employed to systematically investigate the effects of various voltage parameters on partial discharges. These include voltage rise/fall time, voltage pulse width, pulse repetitive rate, duty ratio, voltage polarity, fundamental frequency, and modulation index. Partial discharge inception voltages (PDIVs) and repetitive partial discharge inception voltages (RPDIVs) of the sample are measured with varied voltage parameters. Test results show that voltage rise/fall time is a major affecting factor which reduces PDIVs of the winding sample by 6.5% when it decreases from 800 ns to 100 ns. Based on test results, a hypothetical partial discharge mechanism is presented to explain the effects of fast voltage rise/fall edges. An empirical equation is also derived to estimate PDIVs of a winding sample under various voltage rise/fall time and pulse width conditions.

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“…With increased switching speeds and cable lengths, the motor terminal voltage can rise to twice or even four times of the dc-bus voltage [12]. The RWP is more pronounced in SiC inverter-fed motor drives, where the motor terminal voltage can be doubled with shorter cable lengths, compared to those used in equivalently rated Si-based drives, due to faster switching speed [13].…”

Section: Introductionmentioning

confidence: 99%

Impact of Parasitics and Load Current on the Switching Transient Time and Motor Terminal Overvoltage in SiC-Based Drives

Zhou

Diab

Yuan

2020

2020 IEEE Energy Conversion Congress and Exposition (ECCE)

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The fast switching speed of silicon carbide (SiC) MOSFETs has enabled converters to operate at higher switching frequencies with enhanced efficiencies, achieving performance improvement in motor drive systems. However, the high voltage slew rate (/) due to faster switching speeds results in excessive transient overvoltage at motor terminals, known as the reflected wave phenomenon (RWP). This paper systematically examines the motor terminal overvoltage in cable-fed SiC motor drive systems considering the effects of parasitic elements of SiC MOSFETs and load current during switching transitions. Starting with a half-bridge inverter, the switching transitions are analysed in detail and then extended to three-phase inverters. The theoretical and experimental results show that besides the rising edge of the inverter output waveform, the falling edge also affects the RWP depending on the load current polarity. Also, the motor terminal overvoltage has a non-uniform envelop which depends on the rise/fall switching times of the generated voltages of the SiC inverter, where these times vary with the load current due to the device parasitic capacitance.

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Control of Variable Frequency Drive PWM to Mitigate Motor Overvoltage Due to Double Pulsing in Reflected Wave Phenomenon

Cited by 11 publications

References 14 publications

Impact of High Switching Speed and High Switching Frequency of Wide-Bandgap Motor Drives on Electric Machines

Impact of High Switching Speed and High Switching Frequency of Wide-Bandgap Motor Drives on Electric Machines

A Partial Discharge Study of Medium-Voltage Motor Winding Insulation Under Two-Level Voltage Pulses With High Dv/Dt

Impact of Parasitics and Load Current on the Switching Transient Time and Motor Terminal Overvoltage in SiC-Based Drives

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