Impact of PWM Voltage Waveforms in High-Speed Drives: A Survey on High-Frequency Motor Models and Partial Discharge Phenomenon

Abstract

The insulation system’s dielectric of the electric motor is very often subjected to severe electrical stress generated by the high dv/dt seen at the machine’s terminals. The electrical stress and high reflected wave transient overvoltage are even more evident in case of high-speed machines fed by high-frequency (HF) converters featuring very fast wide-bandgap devices. They are promoting the occurrence of partial discharges and consequently accelerate ageing. As this is serious issue and the main cause of the drive failure, it is important to analyse and characterise the surges at the motor terminals. Several HF models of motors have been proposed in the literature for this purpose. This article presents a survey on HF motor models, which is crucial in understanding and studying the most critical parameter identification and overvoltage mitigation techniques. Moreover, it offers a comparison of the models’ main features as well as a comparison with the experimental voltage waveform at motor terminals. A general overview of the partial discharge (PD) phenomenon is also provided, as it is favoured by HF operation and together with HF motor modelling provides key insights to the insulation ageing issue. In particular, an analysis of the effects of PWM waveform affecting insulation is given, as well as useful methods for developing strategies for the inspection and maintenance of winding insulation.

Genetic algorithm-enhanced linear quadratic control for balancing bicopter system with non-zero set point

“…This instability arises from the inability of the device to cope with excessively fast changes in PWM signals. Furthermore, such rapid changes in current and voltage can increase the risk of device damage [32]. In contrast, the LQ-GA method produces a more stable control signal, making it safer to apply to controller and actuator devices.…”

Analysis of Electrical Aging Effects on AC High Frequency Motor Based on Exchange Market Algorithm Model Parameter Identification

“…Additionally, HF models can be employed for the development and assessment of PD mitigation strategies, such as the design of optimized dv/dt filters or the implementation of active gate driving techniques that shape the PWM voltage pulses originating from the inverter to reduce overvoltages. Several machine models capable of capturing the machine's high-frequency behavior in detail have been proposed in the scientific literature [10]. These HF models can be mainly grouped into four families: lumpedparameter circuit models [11]- [14], multi-section models [15], [16], transmission-line models [17], and analytical models.…”

Power Electronic Circuits for Electric Drives and Renewable Energy Sources

“…The second topic, i.e., power electronics for innovative electric drives, features two papers; one is regarding the hybrid drivetrain with the tractor application [3] and the other the Energies 2022, 15, 5301. https://doi.org/10.3390/en15145301 https://www.mdpi.com/journal/energies review paper on the high-frequency motor models and partial discharge phenomenon [4].…”

“…The innovative full-hybrid driveline based on an electric continuously variable transmission has been analyzed in [4]. System architecture and control have been compared with conventional tractors, while unprecedented features such as power boost, full-electric mode, optimized auxiliary drive and electric power delivery have been discussed and simulated.…”

“…A tractor prototype demonstrates compact layout installation ease. Authors in [4] proposed a review paper on the impact of high-speed drives PWM voltage waveforms on dielectric aging and electrical stress. An extensive discussion of the partial discharge phenomenon and the high-frequency motor models necessary for its study is given.…”