Winding currents contain lots of harmonics if motors rotate at a high speed. This paper addresses two key challenges on the harmonic suppression: 1) using the multiple synchronous rotating frame transformations (MSRFTs) to get the primary signals, and 2) proposing the closed-loop detection system (CDS) to extract the harmonics accurately. First, the mathematical model containing the harmonics was built. Second, the MSRFTs were introduced and the high-precision detection method called the CDS was analyzed. The CDS has a higher harmonic detection accuracy than the open-loop method and can enhance the disturbance rejection capability of the system. Third, the parameter-independent compensation algorithm was proposed to enhance the robustness against the motor parameter variations, which was combined with the compensation calculated by the mathematical model to suppress the harmonics. The effectiveness of the proposed harmonic suppression strategy was verified by the experiments on the turbo molecular pump.

Selective Current Harmonic Suppression for High-Speed PMSM Based on High-Precision Harmonic Detection Method

In this paper, we develop formulation of a multi-objective optimization problem (MOOP) to optimally size a battery unit (BU) ultracapacitor (UC) hybrid energy storage system (HESS) for plug-in electric vehicle (EV). In this application, the objectives were to minimize cost, weight, volume of the HESS simultaneously maximizing the remaining cycle life of the BU at the end of the driving cycle. The MOOP is solved by the non-dominated sorting genetic algorithm type 2 algorithm. Detailed mathematical models for the BU and UC are given. The thermal effect on performance and sizing are also included in the formulation. The power demand by the EV powertrain is shared amongst the BU and HESS by two methods: First is by using wavelet transformation, while the second is by using power split ratio. The ratio of the power (i.e., power split) handled by each storage unit was determined by the optimizer. A sensitivity analysis was conducted for the power splitting ratio verification. The problem was solved for using the urban dynamometer driving schedule and the highway fuel economy test driving profiles. This has resulted in sizing of an HESS with lower cost, volume, and weight than those existing in literature. Finally, the effect of changing the motor type on the MOOP result was investigated.

Hybrid Energy Storage Sizing and Power Splitting Optimization for Plug-In Electric Vehicles

The hybrid electric bus (HEB) presents an emerging solution to exhaust gas emissions in urban transport. This paper proposes a multiport bidirectional switched reluctance motor (SRM) drive for solar-assisted HEB (SHEB) powertrain, which not only improves the motoring performance, but also achieves flexible charging functions. To extend the driving miles and achieve self-charging ability, photovoltaic (PV) panels are installed on the bus to decrease the reliance on fuelsbatteries and charging stations. A bidirectional front-end circuit with a PV-fed circuit is designed to integrate electrical components into one converter. Six driving and five charging modes are achieved. The dc voltage is boosted by the battery in generator control unit (GCU) driving mode and by the charge capacitor in battery driving mode, where the torque capability is improved. Usually, an extra converter is needed to achieve battery charging. In this paper, the battery can be directly charged by the demagnetization current in GCU or PV driving mode, and can be quickly charged by the PV panels and GCUAC grids at SHEB standstill conditions, by utilizing the traction motor windings and integrated converter circuit, without external charging converters. Experiments on a three-phase 128 SRM confirm the effectiveness of the proposed drive and control scheme.

Multiport Bidirectional SRM Drives for Solar-Assisted Hybrid Electric Bus Powertrain With Flexible Driving and Self-Charging Functions

This paper investigates a method of reducing the vibration property of a permanent magnet synchronous motor (PMSM) with dual three-phase windings, especially focusing on carrier harmonics. Electromagnetic excitation force on carrier harmonics, which makes carrier harmonic vibration, is formulated and the relationship of the carrier phase difference between the space and the time phase difference to cancel out the excitation force is calculated for dual three-phase winding PMSM. Then, the carrier phase-shift space vector pulsewidth modulation (SVPWM), which makes any difference between the PWM carrier phase of the first and second windings, is applied to a 24-slot 20-pole PMSM. A test motor is manufactured and measured results reveal that the vibration and sound pressure can be approximately halved at around carrier harmonic and twice carrier harmonic when the carrier phase is π/2 radian compared to conventional in-phase carrier PWM.

Vibration Reduction by Applying Carrier Phase-Shift PWM on Dual Three-Phase Winding Permanent Magnet Synchronous Motor

Due to the coaction of supply harmonics and the harmonics resulting from the motor structures, the mechanism and distribution characteristics of iron losses become more complicated in inverter-fed induction motors. Therefore, accurate prediction and fine analysis of iron loss are very important at the design stage of high-efficiency inverter-fed induction motors. In order to predict the iron losses accurately, this paper proposes a piecewise iron loss model whose parameters vary with the magnitude and frequency of flux density, and two additional flux density terms are introduced to the classical iron loss model considering the nonlinearity of magnetic material and harmonic fields. With this model, the iron losses are calculated for an inverter-fed 5.5 kW induction motor. The results reveal the distribution characteristics of hysteresis and eddy current losses in stator and rotor cores, and the characteristics of additional iron loss caused by harmonic fields. By the comparison of predicted and measured no-load iron loss under different supply voltages and switching frequencies, the proposed model and the analysis results are validated.

Piecewise Variable Parameter Loss Model of Laminated Steel and Its Application in Fine Analysis of Iron Loss of Inverter-Fed Induction Motors

This paper investigates a method to increase fuel economy of motors for an electric vehicle (EV) traction system. The low-torque region of an EV motor is frequently used in everyday urban driving and in fuel economy measurement. Pulsewidth modulation (PWM) carrier harmonic iron loss accounts for a high percentage of total loss for EV motors in this region. This paper reveals the relationship between phase current and carrier harmonic iron loss for a permanent-magnet synchronous motor (PMSM) in the low-torque region. Thus, a novel carrier harmonic loss reduction technique is proposed and applied to two sets of three-phase windings for a concentrated winding PMSM. The loss is successfully reduced in a 70-kW EV motor as well as a two-dimensional finite-element method (2-D-FEM) calculation. The efficiency of the developed motor is calculated and compared with that of a conventional motor in the JC08 mode driving cycle.

PWM Carrier Harmonic Iron Loss Reduction Technique of Permanent-Magnet Motors for Electric Vehicles

This paper is investigated to increase fuel economy of motor for electric vehicles (EVs) traction system. Low torque region of EV motor is frequently-used point in usual urban driving and in fuel economy measurement. Pulse-width modulation (PWM) carrier harmonic iron loss takes up high percentage for EV motors in this region. This paper reveals the relationship between phase current and carrier harmonic iron loss for permanent magnet synchronous motor (PMSM) in low torque region. Then, a novel carrier harmonic loss reduction technique is proposed, which is applied two set of three phase windings for concentrated winding PMSM. The loss reduction effect is tested successfully on a 70 kW EV motor as well as two dimensional finite element method (2D-FEM) calculation. The efficiency of developed motor is calculated and compared with that of conventional motor in JC08 mode driving cycle.

PWM carrier harmonic iron loss reduction technique of permanent magnet motors for electric vehicles

This paper introduces a pulse-width modulation (PWM) method for a two-motor drive system that reduces the propagation of conduction noise to the power supply. This two-motor drive system consists of two motors with each of the two inverters connected to a common DC bus. The proposed method suppresses the common mode voltage ideally to zero by shifting the rise and fall times of the output voltage of each inverter. Our experimental results show that the rise and fall times of the output voltage can be synchronized even when the two inverters are driven at different amplitudes and frequencies. We further confirmed that the proposed method suppresses the propagation of conduction noise to the power supply.

A Study of Conduction Noise Suppression Control for Two-Motor Drive Systems

In noise suppression control that switches between two inverters with opposite phases, the synchronization accuracy of switching limits the noise reduction and bandwidth. To improve the noise suppression control, this paper proposes a control method that detects the rise and fall of the inverter output voltage and compensates for the synchronization error between two inverters. The effectiveness of the proposed method was verified by applying it to the double-three-phase motor drive system; the synchronization error was reduced to 10 ns. 

Conductive‐noise suppression control improved by synchronous compensation for switching

This paper introduces a pulse-width modulation (PWM) method for a two-motor drive system that reduces the propagation of conduction noise to the power supply. This two-motor drive system consists of two motors with two inverters, each of which is connected to a common DC bus. The proposed method suppresses the common mode voltage ideally to zero by shifting the rise and fall times of the output voltage of each inverter. Our experimental results show that the rise and fall times of the output voltage can be synchronized even when the two inverters are driven at different amplitudes and frequencies. We confirm that the proposed method suppresses the propagation of conduction noise to the power supply. 

Shota Hanioka

Papers

PWM Carrier Harmonic Iron Loss Reduction Technique of Permanent-Magnet Motors for Electric Vehicles

PWM carrier harmonic iron loss reduction technique of permanent magnet motors for electric vehicles

A Study of Conduction Noise Suppression Control for Two-Motor Drive Systems

Conductive‐noise suppression control improved by synchronous compensation for switching

Common mode noise suppression control for two‐motor drive systems