초록

An apparatus for use with a switch-mode rectifier for minimizing DC bus voltage without causing current distortion, the apparatus monitoring rectifier saturation and decreasing DC bus voltage until the rectifier is near a saturation point and then maintaining the DC bus voltage at that point.

대표청구항 ▼

[ We claim:] [1.] An apparatus for use with a motor controller, the controller including a PWM switch mode rectifier linked to a utility grid which provides three utility supplied rectifier input AC voltages at rectifier inputs, the rectifier also linked to a DC bus for generating DC voltage on the

[ We claim:] [1.] An apparatus for use with a motor controller, the controller including a PWM switch mode rectifier linked to a utility grid which provides three utility supplied rectifier input AC voltages at rectifier inputs, the rectifier also linked to a DC bus for generating DC voltage on the bus, the controller using rectifier input current feedback signals, DC bus voltage feedback signals and a DC command signal to generate a synchronous signal set including synchronous d and q-axis voltage signals, using the synchronous set to generate a stationary signal set including stationary d and q-axis voltage signals, using the stationary set to generate a modulating signal set including first, second and third modulating signals, providing a triangle carrier signal having a peak amplitude, comparing the modulating signals to the carrier signal to generate control signals for the rectifier to convert the utility supplied input voltages to DC voltage on the DC bus, each of the synchronous, stationary and modulating sets being an intermediate set, the apparatus for limiting the DC voltage to a minimum DC voltage required to generate rectifier input voltages which are greater than the utility supplied input voltages, the apparatus comprising:an amplitude signal generator receiving a first intermediate set's signals and generating an amplitude signal, the first intermediate set's signals defining a vector having a vector amplitude, the amplitude signal being a function of the vector amplitude;a reference signal generator which generates a reference signal as a function of the carrier signal peak amplitude;a first summer mathematically combining the reference signal and the amplitude signal generating an error signal;a regulator receiving the error signal and providing a correction signal as a function of the error signal; anda second summer mathematically combining the command signal and the correction signal generating a modified command signal representing the minimum DC bus voltage signal.