The Application Of The Charge Pump In Driving The Piezoelectric Actuator

Piezoelectric ceramic is a smart material which has been widely used in precision control, micro-nanofabrication, energy recycle, etc. However, piezoelectric ceramic exists nonlinear characteristics of hysteresis and creep. These characteristics affect its positioning precision and accuracy seriously which restricts the scope of application. Solving the problem of hysteresis and creep of piezoelectric ceramic has become a worldwide leading subject. Some approaches have been used to overcome the hyste-resis and creep in domestic and foreign. Because the displacement of piezoelectric is proportional to its drive voltage: a newly construct is presented in this paper: switch capacity charge pump. It can eliminate the hysteresis and creep of piezoelectric ce-ramics effectively.In this paper, the piezoelectric theory is reviewed at first; then analysis the rea-sons of the hysteresis and creep characteristics. According to the traditional drive con-struct, switched capacitor charge pump structure is proposed. Finally, build the ex-periment test platform, test and analysis the results of the driving structure of the switched capacitor charge pump. The new drive method can reduce the hysteresis and creep more effectively. Then, analysis the advantage and disadvantage of the driving method; summary the various parameters on the hysteresis and creep characteristics.The piezoelectric stack used in the experiment is made from 200 layers of ce-ramic stack. The size of piezoelectric stack is 10mm×10mm×18mm. It can with-stand 0 ~ 100V voltage, displacement range can reach 0 ~ 14μm. Experimental results show that the new structure can make a very good linearity; hysteresis characteristic can be reduced. When the displacement frequency is 0.01Hz, the hysteresis size is 2.01%, as the frequency increased; linearity improved, hysteresis also decreased. When frequency is 20Hz, the hysteresis size is 0.57% which is much smaller than the traditional voltage driving. Simultaneously; using this method can make the creep properties better compared to traditional voltage driving. The error can be reduced to 77%. The displacement response becomes more quickly. This drive control method of novel structure, high stability, high control precision, convenient adjustment, enabling the expansion of the scope of application of piezoelectric ceramics.