| 摘要 |
A drive circuit for an electric motor, comprising a switchable DC/AC frequency converter, control means for controlling said frequency converter to deliver a pulse width-modulated excitation signal to the motor, setting means for providing a setting signal for setting a desired motor operation, and comparator means for comparing the current motor operation with the setting signal for driving the control means. The simulator means are arranged for analog simulation of the electrical behaviour of the motor for the purpose of comparing the current motor operation with the setting signal. In an embodiment, a first-order low-pass filter is used for simulating the motor behaviour for the purpose of providing an essentially constant relation between the effective stator voltage and the stator frequency so as to retain a sufficiently large motor torque in the case of an increasing frequency. |
