Insulation design of low voltage electrical motors fed by PWM inverters

Lusuardi, Luca; Cavallini, A.; Calle, M. Gomez de la; Martínez-Tarifa, Juan Manuel; Robles, G.

doi:10.1109/mei.2019.8689431

Cited by 44 publications

(86 citation statements)

References 16 publications

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“…Similar low values (K St ≈ 6) of the streamer constant are reported in the recent literature [35] on the investigation of PDIV for twisted pairs of enameled wire, where the electrode configuration and dimensions of the discharging air gap are similar to those occurring in the present study. The authors in [35] refer to literature that scrutinizes the value of the streamer constant, in particular, the relation K St = ln(N c ), where N c = 10 6 ...10 8 is the critical number of electrons required to initiate the streamer propagation mode of the discharge: "there is no reason apart from tradition for retaining K [St] equal to 18" [36] (p. 729). There thus seems to be a need for better understanding the inception criteria of PD in dielectric-barrier-type electrode configurations under inverter-type medium voltages.…”

Section: Discussionsupporting

confidence: 91%

“…However, the obtained value of the streamer constant K S predicting the observed value of the PDIV is much lower (K S = 4.6...5.2) than the standard value K S = 14...18 traditionally used for determining streamer inception in air [34]. Similar low values (K St ≈ 6) of the streamer constant are reported in the recent literature [35] on the investigation of PDIV for twisted pairs of enameled wire, where the electrode configuration and dimensions of the discharging air gap are similar to those occurring in the present study. The authors in [35] refer to literature that scrutinizes the value of the streamer constant, in particular, the relation K St = ln(N c ), where N c = 10 6 ...10 8 is the critical number of electrons required to initiate the streamer propagation mode of the discharge: "there is no reason apart from tradition for retaining K [St] equal to 18" [36] (p. 729).…”

Section: Discussionsupporting

confidence: 78%

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Endurance of Polymeric Insulation Foil Exposed to DC-Biased Medium-Frequency Rectangular Pulse Voltage Stress

et al. 2019

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The endurance of polymeric insulation foil is investigated under a mixed medium-voltage stress (DC + medium-frequency rectangular pulse) by means of accelerated lifetime testing. A dedicated setup is used that allows us to selectively eliminate the known risk factors for premature insulation failure under medium-frequency pulse voltage stress: partial discharges (PDs) during pulse transitions, excessive dielectric heating, and systemic overvoltages. The obtained results on polyethylenterephtalat (PET) insulation foil suggest that the adequate consideration of these factors is sufficient for eliminating the adverse effects of the pulse modulation under the investigated conditions. Indeed, if all mentioned risk factors are eliminated, the time to failure observed under a pure DC stress is shorter than with a superimposed pulse (keeping the same peak voltage). There is then no indication of an additional detrimental “per pulse” degradation process (i.e., the time to failure is not dependent on pulse frequency). In contrast, when repetitive PDs are present, the lifetime under combined DC + rectangular pulse stress strongly decreases with increasing pulse switching frequency. PD erosion of the foil is quantified by means of confocal microscopy, and the applicability of the streamer criterion for predicting PD inception is discussed.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionsupporting

confidence: 78%

Endurance of Polymeric Insulation Foil Exposed to DC-Biased Medium-Frequency Rectangular Pulse Voltage Stress

et al. 2019

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“…To calculate the applied fields with FEM, the geometric and permitivity (see [17]) data from several magnet wires shown in Table 1 are used 1 .…”

Section: Physics Of Partial Discharge Inception Voltagementioning

confidence: 99%

“…This simplification cannot be assumed for this geometry [18], so the path followed by the electric field lines (the lines that would define the path followed by a free electron) cannot be used in the line integral in Equation 3. 2) Equation 3 is based on Townsend ionization mechanism, whereas the streamer inception mechanism has proven to be effective in previous works [17]. In that case, Equation 3 can be rewritten as:…”

Section: Physics Of Partial Discharge Inception Voltagementioning

confidence: 99%

“…By contrast, authors of [17] question the validity of Paschen's Law for PDIV prediction in turn to turn insulation systems, as the electric fields created by the coils are nonuniform. They used the streamer criterion to predict the PDIV (without including the impregnation varnish), changing the air density to include the effects of temperature in the proposed model.…”

Section: Introductionmentioning

confidence: 99%

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Uncertainty Sources in the Estimation of the Partial Discharge Inception Voltage in Turn-to-Turn Insulation Systems

Calle¹,

Martínez-Tarifa

Solanilla

et al. 2020

IEEE Access

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Partial discharges (PD) are one of the main causes of premature failure in low-voltage motors driven by variable-speed drives. The use of these control systems are being quite extended due to new applications, such as the more electric aircraft (MEA) or hybrid and electric vehicles, and this has pushed research towards appropriate designs of electric motors to avoid, as much as possible, the presence of PD within their windings. This paper presents a model to predict the partial discharge inception voltage (PDIV) in the insulation of low-voltage machines. A value for the secondary ionization coefficient based on a statistical study is also proposed. The deviations of the model are also studied by obtaining the uncertainty of the value of that coeficient and the predicted values of the PDIV for a set of wires. This uncertainty will be compared with other error sources such as generator harmonics and humidity. Finally, the tests are done for different temperatures extend the model applicability. INDEX TERMS Insulation design, inverter-fed machine, partial discharges, Paschen's Law, Temperature, Townsend's coefficients.

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A data-driven approach for exploring partial discharge inception voltage of turn-to-turn insulation in inverter-fed motors

Zhang

Wang

et al. 2023

Electr Eng

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Insulation design of low voltage electrical motors fed by PWM inverters

Cited by 44 publications

References 16 publications

Endurance of Polymeric Insulation Foil Exposed to DC-Biased Medium-Frequency Rectangular Pulse Voltage Stress

Endurance of Polymeric Insulation Foil Exposed to DC-Biased Medium-Frequency Rectangular Pulse Voltage Stress

Uncertainty Sources in the Estimation of the Partial Discharge Inception Voltage in Turn-to-Turn Insulation Systems

A data-driven approach for exploring partial discharge inception voltage of turn-to-turn insulation in inverter-fed motors

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