Higher Dynamics with Energy Recovery Driver Design
Most drive electronics for piezo actuators are based on linear amplifiers or charge amplifiers. For industrial 24/7 high dynamics applications, driving large capacitance actuators, the energy consumption can be a factor to be considered. With typical periodic dynamic applications and linear amplifiers, the energy to charge and discharge a piezo actuator is lost after each cycle – actually it is turned into heat that needs to be dissipated.
A new patented amplifier design with an energy recovery circuit is available with standard drivers covering up to 6KVA. The system is based on a combination of PWM (pulse width modulation) where the pulse width of the drive voltage is modulated and the relatively large piezo capacitance smoothes out the signal. In addition, a patented circuit for energy recovery is also integrated. It stores a portion of the returned energy when the piezo discharges in a capacitor, making it available for next charging cycle. The result is significantly higher efficiency with energy savings up to 80%.
Weight savings in the amplifier and significant reduction in the amplifiers heat dissipation are additional benefits. In contrast to conventional switched amplifiers (Class D), the new patented energy recovery piezo amplifier is run in both current and voltage control mode.
This is critical for applications in the field of active vibration control.
Additional Temperature Monitor to Protect the Piezo Mechanisms
The energy loss in static piezo operation is negligible. In continuous dynamic operation, especially with powerful drivers, it is recommended to monitor the temperature of the piezo mechanism. Integrated sensors are available to hook up to the driver and shut it down when a preset threshold is exceeded.