1、PDF外文：http:/ Characteristics of IPMSM Speed Control System Without Electrolytic Capacitor Tatsuya Nishihara,Shigeo Morimoto,and Masayuki Sanada OsakaPrefectureUniversity,1-1,Gakuen-cho,Nakaku,Sakai,Osaka,Japan Abstract Elimination of the electrolytic capacitor in the inverters of motor system
2、driven domestic appliances is desirable, because the electrolytic capacitor increases the appliance volume and has the problem of short lifetime. Two different control methods for an interior permanent magnet synchronous machine(IPMSM)speed control system without an electrolytic capacitor are compar
3、ed. The performance of the speed control system is then examined using the superior control method and the influence of the motor parameters on the IPMSM drive performance without an electrolytic capacitor is examined. As a result, the influence of inductance is clarified. Index Terms eliminat
4、ion of electrolytic capacitor, maximum torque per ampere control, flux weakening control, IPMSM. I.INTRODUCTION Recently, electrical power converters such as the diode rectifier and inverter have been adopted in some domestic electric appliances. However, with an electrical power conver
5、ter, high performance, high efficiency, downsizing, weight saving, low-cost, and long life are desirable. Additionally, harmonic problem at power side must be considered. These are important factors to consider for the evaluation of electrical power converters.1-3 Therefore, there have been ma
6、ny studies regarding power conversion methods and circuit construction. In general, AC-DC-AC electrical power converters are used as AC-AC frequency converters. However, this method requires a high-capacity electrolytic capacitor, and the size of the electrolytic capacitor for a converter is large a
7、nd the life of the electrolytic capacitor is short. Therefore, there have been many studies regarding control methods for speed control systems without electrolytic capacitors.4-6In this study, two different control methods for an interior permanent magnet synchronous machine(IPMSM)speed control sys
8、tem without an electrolytic capacitor are compared. The performance of the speed control system is examined using the superior control method and the influence of the motor parameters on the IPMSM drive performance without an electrolytic capacitor is examined. II.SIMULATION MODEL The simulati
9、on model for the IPMSM speed control system is shown in Fig.1.The dc-link voltage Vdc is obtained through capacitor C. The rotor position and motor speed are detected using an encoder. At the current control part, d-and q-axis voltage references are obtained through the decoupling and PI controllers
10、. The q-axis current reference iq*is obtained by the PI controller. The d-axis current reference id*is determined using two control methods .One method is the id=0 control method, which maintains the d-axis current reference at zero. The other method is the maximum torque per ampere and flux weakeni
11、ng(MTPA+FW) Firstly, the voltage limit value Vom is given by(1)from the dc-link voltage Vdc. dco m a a m322VV R I （ om 0V ）（ 1） The d-axis current reference id*on the MTPA control is given by(2),and id*on the FW control is given by(3).When the calculated value in the square root is negative, t
12、he value of the square root is limited to zero. When the calculated value of(3)is positive, id*is limited to zero. 2* * 2aadq2qd qdii2 4LL LL （ 2） 2 2*a o md q qdd1iiV LLL （ 3） 22*0 d d a q qiiV L L （ 4） The induced voltage Vo is given by(4).The maximum torque per ampere and flux
13、 weakening control method selects id*by which the induced voltage Vo becomes smaller. Fig.1.Simulation model. III.COMPARISON OF TWO DIFFERENT CONTROL METHODS The specifications of the simulated machine are shown in Table.I.A comparison of the id=0 and MTPA+FW control methods is pre
14、sented in Fig.2.The motor efficiency is calculated by dividing the mechanical output power by the electrical input power.Iron loss is neglected.The reference speed is 1800 1min and the load torque is 1.0 Nm in the simulations.When the capacity of the capacitor is small,the motor efficiency decreases
15、 and the torque ripple increases.The MTPA+FW control method achieves higher motor efficiency and smaller torque ripple than the id=0 control method. IV.CHARACTERISTICS OF THE MAXIMUM TORQUE PER AMPERE AND FLUX WEAKENING CONTROL METHOD The characteristics of the MTPA+FW control method wer
16、e examined in detail.The reference speed and load torque used were 1800 min-1 and 1.0 Nm,respectively.The dc-bus voltage characteristics are shown in Fig.3,and those of the converter input voltage and current are shown in Fig.4.When the capacity of the smoothing capacitor is 1000F,the dc-bus voltage dcV is smoothed.However,the dc-bus voltage Vdc is not smoothed when the capacity of the smoothing capacitor is 10F.(assuming a film capacitor)In addition,when the capacity of the smoothing capacitor is 1000F,the
