SIMULATION AND MEASUREMENT OF SYNCHRONOUS MOTOR PROTOTYPE WITH AN EXTERNAL ROTOR BY USING PERMANENT MAGNETS

Transcription

1 Zeszyty Problemowe Maszyny Elektryczne Nr 4/214 (14) 25 Ján Kaňuch, Želmíra Ferková Technical University of Košice, Slovakia SIMULATION AND MEASUREMENT OF SYNCHRONOUS MOTOR PROTOTYPE WITH AN EXTERNAL ROTOR BY USING PERMANENT MAGNETS Abstract: This paper presents the design, simulation and measurement of a synchronous prototype with an external rotor by using permanent magnets which was optimized for high-torque, in-wheel operation. Based on geometric dimensions, the 3D solid model was created in ANSYS/Maxwell program. The electromagnetic design was calculated in ANSYS/RMxprt program. The cross section with graphical presentation of magnetic induction in particular parts of electromagnetic circuits and the simulated and measured characteristics of the are shown. Keywords: synchronous, permanent magnet, ANSYS/Maxwell program 1. Introduction Synchronous s operate at a constant speed in absolute synchronism with the line frequency or, respectively, can be supplied also from a frequency converter. Servo drives with permanent magnet (PM) s fed from static inverters are finding applications on an increasing scale. PM servo s with continuous output power of up to 15 kw at 15 rpm are common. Rare-earth PMs have also been recently used in large power synchronous s rated at more than 1 MW [1]. Currently, synchronous electric with permanent magnets (PM) and external rotor gradually is applied in electric vehicles drives, and it is stored directly in the wheel. Hub s, also called in-wheel s, were first patented in the 188s. In 1899 the Viennese firm of Lohner & Co. built a car powered by battery-driven hub s. A member of the Jacob Lohner & Co. staff was also Ferdinand Porsche, a native of Bohemia, from Vratislavice nad Nisou. Ferdinand Porsche, as 23 year old, built his first car on the basis Lohner Electric Chaise (Fig. 1). This car was also unique as the world's first front wheel drive. A news report at the time described the development of the first-ever transmission-less vehicle as a revolutionary innovation. The electric in the (Fig. 2) hubs of the front wheels had output of 1.8 kw at 12 rpm. Fig. 2. Electric in hub of the wheel Fig. 1. Lohner-Porsche Mixte hybrid car The 44-cell, 8-volt rechargeable battery with a capacity of 3 Ah gave the car a range of 5 km/ 3 miles between recharges. The maximum speed was 5 km/h. Slow speed of the electric permitted direct drive and inwheel installation. The operated without chains, and hence without mechanical power loss. Consequently, the electric was extremely efficient and was almost silent during operation [2].

2 26 Zeszyty Problemowe Maszyny Elektryczne Nr 4/214 (14) 2. Model and simulation of synchronous with PM external rotor This chapter presents results of the electromagnetic proposal for a synchronous with external rotor with permanent magnets, simulation of electromagnetic field and its operating characteristics. Basic electrical characteristics have been developed on the basis of operational requirements for the, and are shown in Table 1. Table 1. The synchronous parameters Parameter Value Rated power 3 kw Rated voltage 3 x 82 V (Y) Rated current 27 A Rated torque 38 N.m Synchronous speed 75 rpm Electromagnetic design of was calculated and optimized in ANSYS/RMxprt program. Based on required electrical parameters and the geometric dimensions resulting from the mount, designed has been a 3D model of electromagnetic circuit of the in ANSYS/Maxwell program (Fig. 3). Fig. 4. Magnetic field of synchronous U [V] InducedVoltage Curve Info InducedVoltage(Faza_C) InducedVoltage(Faza_A) InducedVoltage(Faza_B) Time [ms] Fig. 5. Induced voltage calculated by Ansys/Maxwell 3D Simulation of the and load torque is shown in Fig. 6. The speed of synchronous was 75 rpm. torque [NewtonMeter] torque Curve Info Torque LoadTorque Fig. 3. The 3-D model of synchronous with PM The following are simulation results of the synchronous electric with external rotor and PM. Simulation of electromagnetic field of the synchronous with PM is shown in Fig. 4. Figure 5 shows simulation of the induced voltage in all three phases of the synchronous machine Time [ms] Fig. 6. Simulation of the and load torque calculated by Ansys/Maxwell 3D 3. Structural design of synchronous The construction and external dimensions of the are designed so that the can be easily positioned and mounted onto a traditional 14" steel rim wheel. The 3-D solid model of stator synchronous has been created based on geometric dimensions of the optimized simulation. The 3D model is presented in Figure 7. In the stator illustration shown are also the winding and shaft.

3 Zeszyty Problemowe Maszyny Elektryczne Nr 4/214 (14) 27 Fig. 7. Stator of the with winding and shaft The 3-D solid model of rotor synchronous with permanent magnets is presented in Figure 8. Fig. 9. Cross-sectional view of the synchronous Fig. 1. 3D solid model of the synchronous Fig. 8. Rotor of the synchronous with permanent magnets Cross-sectional view of the synchronous is shown in Figure 9. Figure 1 shows the general view of the 3D solid model of synchronous with permanent magnets and inverse rotor. 4. Measurement of synchronous prototype Based on structural design of the referred to in chapters 2 and 3 devised was the functional prototype. Fig. 11. The synchronous prototype

4 28 Zeszyty Problemowe Maszyny Elektryczne Nr 4/214 (14) Simulation results of synchronous were attained through comparison of measurements on a real synchronous. Used for practical measurements was the synchronous, photo of which is displayed in Fig Measurement of generator operation When measured in no load generator, the waveforms were recorded with an oscilloscope showing the voltage induced in individual phases. Figure 12 shows waveforms of induced voltages in the phases of the generator for the speed of 75 rpm. Shown in Figure 13 is plot of the terminal voltage and efficiency versus mechanical torque for generator speed of 75 rpm. The measured quantities are indicated by crosses. Whilst the average efficiency is 94%, the voltage drop is up to 19%. Figure 14 shows waveforms of voltage in the first phase (in blue) and of the load current (in red). The generator is loaded with constant current of 2 A (RMS). Fig. 14. Measured waveforms of voltage and current Fig. 12. The measured induced voltages In this measurement, phase voltage reached 47.6 V (RMS) and line-to-line voltage 82.6 V (RMS). Frequency analysis of phase voltages (no load generator) is shown in Table 2. Table 2. Frequency analysis of phase voltages Order U1[%H1] U2[%H1] U3[%H1] When load is exerted on the generator (resistive load), its terminal voltage drops. ] [V U s T [Nm] Us Efficiency [-] c y n ie fic E Fig. 13. Measured quantities for load on generator Frequency analysis of phase currents (for load current of 2 A) is shown in Table 3. Table 3. Frequency analysis of phase currents Order I1[%H1] I2[%H1] I3[%H1] Measurement of load operation When measuring synchronous machine in load operation the machine is connected to a rated supply voltage of 82 V (RMS), with frequency of 5Hz. During loading of the the supply voltage remains constant. The synchronous was operated at constant speed (75 rpm) and was loaded by a torque. At constant mechanical speed, the mechanical output power is equivalent to mechanical torque on the shaft. Shown in Figure 15 is the plot of torque, the input power and the mechanical power supplied to the rated voltage versus phase current for speed of 75 rpm. The measured quantities are indicated by crosses.

5 Zeszyty Problemowe Maszyny Elektryczne Nr 4/214 (14) ] [W m c, P P Pc Pm T ] m [N T inharmonic. The operates under excitation. Figure 18 shows waveforms of supply voltage in the first phase (in blue) and current of (in red). The is loaded with constant torque of 36.6 Nm and operates as overexcited I [A] Fig. 15. Measured waveforms of torque and the powers. Figure 16 shows the plot of efficiency versus mechanical torque for synchronous speed of 75 and rated supply voltage of 82 V (RMS). The measured quantities are indicated by crosses. [-] c y n ie fic E M[Nm] Fig. 16. Measured efficiency of synchronous Figure 17 shows waveforms of supply voltage in the first phase (in blue) and current of (in red). The is loaded with constant torque of 1 Nm. Fig. 17. Measured waveforms of supply voltage and the current T=1Nm If the is loaded with small torque (T=1 Nm), then the waveform of current contains higher harmonics and is very Fig. 18. Measured waveforms of supply voltage and the current T=36.6 Nm If the is loaded with rated torque, then the waveform of current contains lower of the higher harmonics and is roughly sinusoidal. Frequency analysis of phase voltages (for load torque 36.6 Nm) is shown in Table 4. Table 4. Frequency analysis of phase voltages Order U1[%H1] U2[%H1] U3[%H1] Frequency analysis of phase currents (for load torque 36.6 Nm) is shown in Table 5. Table 5. Frequency analysis of phase currents Order I1[%H1] I2[%H1] I3[%H1] Conclusions The present paper shows initial results of simulation and measurement of synchronous machine prototype with an external rotor and permanent magnets. When the synchronous machine works as a generator (resistive load) efficiency is higher than 9%. Efficiency of the synchronous is higher than 8%. (for

6 3 Zeszyty Problemowe Maszyny Elektryczne Nr 4/214 (14) load torque higher than 15 Nm). The is designed to triple the torque overload. The maximum measured load torque of the synchronous was 4.2 Nm. The synchronous is designed to withstand three times the torque overload and is intended for in-wheel operation. Therefore, it is anticipated that performed will be future measurements of a synchronous machine supplied with variable frequency converter. 6. Bibliography [1]. Gieras J.F., Wind M.: Permanent magnet technology Design and Applicatios. Ohio, United States of America, 22 [2]. Ferdinand Porsche ( ), Available on the internet: < [3]. Skala B.: The Heat and Cooling of Electronically Switching Synchronous Machine as a Main Drive of a Car. International Conference on Applied Electronics Location: Pilsen, Czech Republic, sept. 7-8, 211 [4]. Miksiewicz R.: Właściwości silnika bezszczotkowego prądu stałego z magnesami trwałymi o różnych rozpiętościach uzwojeń stojana, Zeszyty problemowe Maszyny Elektryczne, Nr. 87/21, str. 215, Katowice 21 [5]. Glinka T. Jakubiec M.: Silniky elektryczne z magnesami trwałymi umieszconymi na wirniku, Zeszyty problemowe Maszyny Elektryczne, Nr. 71/25, str. 13, Katowice 25 [6]. Kisielewski P., Antal M., Gierak D., Zalas P.: Zastosowanie magnesów trwałych w silnikach elektryczych duzej mocy, Zeszyty problemowe Maszyny Elektryczne, Nr. 92/211, str. 187, Katowice 211 [7]. Rossa R.: Zastosowanie metody polowoobwodowej do obliczania parametrów silników synchronicznych z magnesami trwałymi przy pracy synchronicznej, Zeszyty problemowe Maszyny Elektryczne, Nr. 72/25, Katowice 25 [8]. Bernatt J., Stanisław G.: Nowe rozwiązanie konstrukcyjne dwubiegunowej prądnicy synchronicznej z magnesami trwałymi, Zeszyty problemowe Maszyny Elektryczne, Nr. 72/25, Katowice 25 [9]. Pistelok P., Kądziołka T.: Nowa seria wysokospravnych dwubiegunowych generatorów synchronicznych wzbudzanych magnesami trwałymi, Zeszyty problemowe Maszyny Elektryczne Nr 1/213 cz. II. str. 65, Katowice 213 [1]. Pyrhönen L., Jokinenm T., Hrabovcová V.: Design of Rotating Electrical Machines, John Wiley & Sons, Ltd, p [11]. Zawilak J., Zawilak T.: Minimization of higher harmonics in line-start permanent magnet synchronous. Micromachines and servosystems, MiS '6. International XV Symposium, s , Soplicowo, Sept. 26 [12]. Salminen P.: Fractional slot permanent magnet synchronous s for low speed applications. Diss. Lappeenranta University of Technology, p. 198, Lappeenrannan teknillinen yliopisto, 24 Authors Ing. Ján Kaňuch, PhD., is with Department of Electrical Engineering and Mechatronic, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Letná 9, 41 Košice, Slovakia. jan.kanuch@tuke.sk, tel.: Assoc. professor, Ing. Želmíra Ferková, PhD., is with Department of Electrical Engineering and Mechatronic, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Letná 9, 41 Košice, Slovakia. zelmira.ferkova@tuke.sk, tel.: Acknowledgment We support research activities in Slovakia. Project is co-financed from EU funds. This paper was developed within the Project: "Centrum excelentnosti integrovaného výskumu a využitia progresívnych materiálov a technológií v oblasti automobilovej elektroniky", ITMS (5%) The financial support of the Slovak Research and Development Agency under the contract No. APVV is acknowledged. (5%)