Investigation Study of Multi-Mode Multi-Speed Operation Method for Surface-Mounted Permanent Magnet Synchronous Machines

Abstract

Typically, a surface-mounted permanent magnet synchronous machine (SPMSM) has a poor flux-weakening performance due to its low synchronous inductance; hence, its speed is proportional to the supply voltage. A relatively high DC-link voltage is required to operate an SPMSM at higher speeds. This paper proposes a multi-mode multi-speed operation method to overcome this issue. With this method, the total line-to-line back electromotive force (EMF) is modified using the winding switching. Each phase of the stator winding is divided into two equal coils. There are four modes of operation of the machine. In mode I, the three-phase stator winding is connected in a wye configuration. In modes II, III, and IV, the winding is reconfigured such that the sum of the individual back EMFs of the coils exhibits a difference in voltages between the line terminals. The back EMF in these modes decreased by 1.74, 3.67, and 6.49 times, respectively, compared with that in mode I. This resulted in a four-speed operation, with base speeds of 1, 1.97, 3.68, and 7.47 pu in modes I-IV, respectively. Herein, the analytical model of the machine and drive topology are explained and demonstrated. Simulation results obtained using the 2-D finite element method are presented along with the experimental measurements to verify the feasibility of the proposed method. INDEX TERMS flux weakening, multi-speed operation, permanent magnet synchronous machine, winding configuration, winding switching. LIST OF ABBREVIATIONS Back EMF Back electromotive force BLDC Brushless DC CAD Computer-aided design CD Circle diagram FEA Finite element analysis FPGA Field-programmable gate array IGBT Insulated-gate bipolar transistor

Improvement of the Constant-Power Speed Range of Surface-Permanent Magnet Machine Using Winding Switching

“…The analytical requirements for CPO are presented in this section. The analysis is based on the analytical model from [23], which is shown below.…”

“…The next method involved the use of a voltage boost converter to increase the available voltage; however, this converter often required a large inductor, which resulted in a large drive cost and bulkiness [8], [9]. The winding switching methods changed the winding configuration using external switches to decrease the effective back EMF [10]- [23].…”

“…The flux linkage was decreased up to 3.73 times for a four-pole machine, and in [18], the possibility of the constant-power operation of a twopole machine using this winding switching was proved. In [22] and [23], the cumulative/differential winding switching was implemented on a three-phase single inverter, and the transistor number was decreased; however, the constant power operation (CPO) was not achieved. Therefore, this method could be implemented only in discrete-type drives.…”

Speed Range Extension of Dual-Stator PM Machine Using Multi-Mode Winding Switching Strategy

“…The most frequently used method for solving this issue is applying a negative d-axis flux weakening (FW) current to reduce the back-electric motive force (back-EMF), which inevitably leads to extra copper loss and potential demagnetization risk of PMs. Other FW concepts have been introduced to extend the speed range of PM machines, such as hybrid excitation [4,5], memory machines [6,7], variable flux leakage [8], mechanical-variable-flux [9], and winding switching (WS) [10][11][12][13][14][15][16][17][18][19][20][21]. Amongst them, the WS strategy does not require a change in the machine structure, but only an external circuit to reconfigure the winding connection, which has, in theory, good compatibility to all PM machines.…”

A Comparative Study on Reduced-Order Disturbance Observer-Based Optimal Control Strategies for Surface-Mounted PMSM Drives

“…Permanent magnet synchronous motor (PMSM) drives such as surface-mounted PMSMs (SPMSMs) and interior PMSMs (IPMSMs) have been applied in various industrial sectors including automation robots, machine tools, and electric vehicles because of their clear benefits such as simple structure, wide speed range, high efficiency, and high power density [1]- [3]. However, there is a challenging task for the PMSM drives to achieve a robust control performance in the presence of system nonlinearities and external disturbances [4], [5].…”