1. Variable Time Step Control for Six-Step Operation in Surface-Mounted Permanent Magnet Machine Drives.
- Author
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Park, Jaeyong, Jung, Sungho, and Ha, Jung-Ik
- Subjects
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PERMANENT magnet motors , *ELECTRIC field strength , *PULSE width modulation , *DYNAMICAL systems , *HARMONIC analysis (Mathematics) , *VOLTAGE control - Abstract
The six-step operation of surface-mounted permanent magnet machine drives in a flux weakening region has many advantages compared to the pulse width modulation mode, such as the reduced switching loss and fully utilized inverter output voltage. However, if the ratio of the sampling frequency to the fundamental frequency is low in fixed sampling system, the low-frequency oscillation in the current can be incurred in the six-step operation. The low-frequency current causes a system stability problem and reduces system efficiency due to an excessive heat and high power loss. Therefore, this paper proposes the variable time step controller for six-step operation. By updating an output voltage, sampling phase currents, and executing the digital controller synchronized with the variable sampling time, the turn
on andoff switch signals for six-step operation can be generated at the exact moment. As a result, the low-frequency oscillation in the phase current can be eliminated. In addition, the system transfer function of the proposed control method is discussed for the system stability and system dynamic analysis. The effectiveness of the proposed method is verified by the comparative simulation and experimental results. [ABSTRACT FROM AUTHOR]- Published
- 2018
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