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The armature field for permanent magnet brushless (PMBL) machine working as DC motor is different from that as AC machine, which causes that the iron losses of PMBL DC motor are not equal with those of PMBL AC machine. An experimental system is designed to separate the iron losses due to armature field from other losses for PMBL DC motor and AC generator. The analysis results of the test data for the prototype PMBL machine of 30kW show that the iron losses due to armature field for the prototype as the DC motor are much more than that as the AC generator, and the iron losses due to armature field in rotor for the PMBL DC motor is more than that for the PMBL AC generator.

This paper presents two high speed brushless DC (BLDC) prototype motors: one is related to the surface-mounted permanent magnet (SPM) rotor, the other to the interior permanent magnet (IPM) rotor. The IPM rotor is a combination of magnets magnetized in tangential direction and in radial direction. As for the two prototype motors, the magnetic field distribution in the air gap calculated by 2D finite element analysis (FEA), the back electromotive force (EMF) waveforms obtained by 2D FEA and test, and the test speed-torque curves are compared respectively. The comparison results suggest that the leak flux in the IPM rotor reduces the air gap flux per pole and that the no-load speed and the speed-torque curve slope of the IPM motor are much greater than the no-load speed and the speed-torque curve slope of the SPM motor.

This paper focuses on the braking of interior permanent magnet synchronous machine (IPMSM) driving system. IPMSM motor has strong rotor saliency and extended constant power operating range and is widely used in the field of electrical traction. In the battery-supplied electric drive system, energy saving becomes critical because of the limited energy. Proper braking must be done to feed back the energy to battery and capacitance and to improve energy utilization. Several braking methods are analyzed and a novel braking control strategy is proposed, which takes the feedback current as the control object to set the speed command in different working conditions, including inertia and load monitored in real time, so as to feed back the regenerated energy and brake within the scope of the maximum permissible battery current. The simulation based on Matlab/Simulation is given, and a contrastive analysis of the system physical changes is done between the situations of unlimited speed dump and addition of speed regulation.

Salient-pole permanent magnet synchronous motor has the characteristic of high power density and high efficiency, quick response, high reluctance torque component, and excellent flux weakening function. Consequently, it is quite suitable for electric traction and electrical vehicle applications. In the condition of limited lab power supply and load condition, this paper presents a design of proportional compression motor based on intensely research of salient-pole permanent magnet synchronous motor for light-weight rail vehicle. The motor design includes configuration design, electromagnetic parameters check, and thermal analysis by using the method combining field and circuit. Moreover, the affect of armature reaction towards flux weakening control is analyzed. The HIL experiment results verify the design. The design method presented in this paper provides reference in the research of salient-pole permanent magnet synchronous motor for electrical traction vehicle.

The study and applications of high power density motor (HPDM) have received more attentions urgently by motion control experts. This paper discusses a drive method used to a kind of special high power density asynchronous motor, which we designed and its power density is more than 1.6 kW/kg. But its frequency conversion adjustable speed drives (ASDs) has particularity, such as: high output torque, harmonic, common-mode voltage, current distorted and loss factor etc. Harmonic can result in the calorific severity of HPDM. The ac/dc/ac conversion system used to provide ac voltages with adjustable frequency in the ASD, consists of a voltage source inverter (VSI). The design adopted an inverter output Passive Filter on drive inverter's hardware structure, and introduced a sort of Over-modulation algorithm for Space Vector PWM, which is proposed on inverter's software control. It is shown that the proposed approach can achieve the characteristic demands of ASD used to HPDM.

Brushless DC motor (BLDCM) has been widely used in drive systems and servo control because of its fast response, high power density and high efficiency and so on. It is usually driven by a hard-switching PWM inverter, which has low switching frequency, high switching loss, high electro magnetic interference (EMI) and acoustic noise, etc. To solve the drawbacks of the voltage source type hard switching inverter, many types of resonant DC link inverters have been widely studied. However, these inverters have such drawbacks as high voltage stress of the devices, delta modulation, threshold limit of inductor current or capacitor voltage and sophisticated control. This paper proposed a novel zero voltage transition parallel resonant DC link voltage source inverter (ZVT-PRDCL-VSI) for BLDCM drive systems. The inverter possess advantages of low switching power loss, low inductor power loss, small device voltage stress, simple control scheme and no unbalancing problem of neutral-point voltage. The operation principle and control scheme of the inverter are analyzed. The validity of the circuit is verified by simulation and experimental results.