Improved motion control and energy consumption for sensorless electromagnetical actuators

Reliability, noise emission and system costs of variable valve actuation applications and impulse charge systems highly depend on an intelligent electronic motion control. A sensorless motion control can provide low landing velocity, minimum energy consumption and high robustness against variations of supply voltage and armature forces. The applied algorithm only relies on the coil current and the coil voltage and needs no further position or speed sensor. At the beginning of the armature movement, the induced voltage allows a sensorless detection of the lift off time and a compensation of the disturbing forces. Another important design aspect for the total system is the energy consumption. A high efficiency of the electrical system is reached by an internally generated overvoltage and an optimum current waveform. Minimum hardware and software effort are required for the realization, which provides substantially lower system costs compared to alternative concepts with geometrical or magnetic field sensors.