Patent ID: 6333610
Filing Date: 2001-12-25
Classification: H02P

Abstract:
A speed control device for use with an electronically commutated multiphase electric motor, comprising:a plurality of phase shifters;a sensor signal evaluation device, evaluating rotor position sensor signals;a time block pulse pattern source, providing at least two distinct time block pulse patterns, each assigned to a specific motor speed;a switching frequency source, providing at least one switching frequency that is below the audible frequency range; anda controller,wherein the phase shifters control delivery of unidirectional and unpulsed power during definable time blocks to motor phases of the electric motor from a constant voltage supply, thereby creating torque, andwherein the controller controls the phase shifters in accordance with the evaluated rotor position sensor signals and the time block pulse patterns and alternately switches between the time block pulse patterns at the switching frequency.