Common-Mode Current Prediction and Analysis in Motor Drive Systems for the New Frequency Range of 2–150 kHz

Abstract

Due to the significant advances in fast switching semiconductor devices, harmonic emissions caused by the adjustable speed drives (ASDs) have been changed in terms of frequency range and magnitude. The frequency range of 2-150 kHz has been distinguished as a new interfering frequency range, disturbing the distribution networks. This paper proposes a behavioral model of an AC motor to predict the common-mode (CM) current in ASDs. An approach is presented to calculate the parameters of the model, through which the dominant impact of each element at a specific frequency is considered. Moreover, along with the proposed motor model, a system modeling strategy is presented for filter design considerations at the emerging frequency range of 2-150 kHz. To verify the effectiveness of the proposed model, real-time experiments are conducted. The results prove that the introduced model can accurately predict the resonances of the CM loop created by the motor. Consequently, the proposed model is suitable for EMI filter design covering the 2-150 kHz standard.

Analysis of 0–9 kHz Current Harmonics in a Three-Phase Power Converter Under Unbalanced-Load Conditions

“…These terms denoted by s a,ω0 , s b,ω0 , and s c,ω0 need to be multiplied by the positive-sequence current of their corresponding phases in (8) to (10). By manipulating the results of these multiplications, the equations to consider the impact of positive-sequence current of load at phases a to c are obtained as given in (11) to (13).…”

“…This equation can be used to estimate the current harmonics below and above 9 kHz by manipulating the values of m and k. However, the value of circuit parameters above 9 kHz varies significantly due to switching transient effects on PWM pulses, the saturation of magnetic elements, and the high-frequency characteristic of electrolytic capacitors. Therefore, the model of the system needs to be modified comprehensively, as described in [11], to study the current harmonics above 9 kHz. This is the main reason that the standardization committees separate the 2-150 kHz frequency range to 2-9 kHz and 9-150 kHz, considering different measurement methods based on International Electrotechnical Commission (IEC) and international Special Committee on Radio Interference (CISPR) standards [11].…”

“…Therefore, the model of the system needs to be modified comprehensively, as described in [11], to study the current harmonics above 9 kHz. This is the main reason that the standardization committees separate the 2-150 kHz frequency range to 2-9 kHz and 9-150 kHz, considering different measurement methods based on International Electrotechnical Commission (IEC) and international Special Committee on Radio Interference (CISPR) standards [11]. In this article, the target is estimating and analysing the current harmonics across dc-link below 9 kHz at an unbalanced-load condition.…”

“…The existing standards only cover the harmonics between 0-2 kHz and above 150 kHz based on IEC 61000-3-2, IEC 61000-3-12, and CISPR (International Special Committee on Radio Interference). Consequently, 2-9 kHz harmonics have become a crucial topic of standardisation committees, such as IEC SC77A WG1, WG8, and WG9, for being considered in the new regulations and standards [11].…”

Nonlinear Effects of Three-phase Diode Rectifier on Noise Emission in the Frequency Range of 2–9 kHz

“…According to IEC activity, the frequency range has been split into two main frequency bands as 2-9 kHz and 9-150 kHz. In parallel to the standardisation activity, recent studies on 2-150 kHz frequency range have been presented in [4]- [8] related to emission modelling of different converter topologies. Even though 2-150 kHz range is new for emission studies, the Differential Mode (DM) emission modelling beyond 150 kHz is well discussed for DC-voltage fed three-phase power converters in [9]- [11] , for grid connected-three-phase bucktype PWM rectifier topology in [12] and for grid connectedthree-phase diode rectifier-Inverter topology in [13].…”