STARTING-PROCESS CONTROLLER FOR STARTING A PIEZOMOTOR

摘要

The invention relates to a starting-process controller for starting a piezomotor (4), having a voltage-controlled oscillator (1)(VCO), a power output stage (2), and a resonant converter (3), wherein the oscillator (VCO) generates the control signals required for the power output stage (2), and the resonance converter (3) converts the stepped output voltage from the power output stage (2) into a sinusoidal voltage at the output of the resonance converter (3), with which voltage the resonance converter (3) drives the piezomotor (4). The motor current that flows when the piezomotor (4) is driven is measured and compared with the phase of the drive voltage in a phase comparator (6). The output signal from the phase comparator (6) then is a measure for the phase difference at the time between current and voltage. A phase-locked loop filter (8) smoothes the phase-difference signal, which in turn controls the oscillator (1)(VCO). This starting-process controller (11) comprises a start-assisting circuit element (10) that fixes the output voltage from the phase-locked loop filter (8) at start-up and thus applies a constant voltage to the input of the voltage-controlled oscillator (1)(VCO).