| 摘要 |
PURPOSE:To enable control with less torque ripple and less iron loss and with no commutation overlap angle decrease, by performing lead angle control and field weakening control in an entire range from a base speed to a rated maximum speed. CONSTITUTION:In a range from the stoppage to the base speed of a synchronous motor 5 driven by an inverter 4, the field current If is kept constant and the terminal voltage Et is raised in proportion to the velocity. In that range, a control lead angle beta, a commutation margin angle gamma and a commutation overlap angle u are constant and an output P increases with the rise in the velocity and reaches a prescribed level at the base speed. As soon as the base speed is exceeded, field weakening control is started. In an entire range from the base speed to a rated maximum speed, the field current If of the synchronous motor 5 is gradually decreased, the rising rate of the terminal voltage Et is made smaller than that of the revolution speed and the terminal voltage Et is linearly changed so that the terminal voltage reaches a set level at the rated maximum speed. |
