Research of Piezoelectric Ceramics Power with High Frequency and Low Ripple
|School||Harbin Institute of Technology|
|Course||Instrument Science and Technology|
|Keywords||piezoelectric ceramic power signal generate high speed data quisition micro-position platform|
Micro-displacement position technology is a key factor in nanotechnology stage. Piezoelectric ceramic actuator generates micro-displacement by converse piezoelectric effect. For its small size, high resolution, high frequency response and other advantage it becomes an ideal micro-displacement device. Ultra-precision micro-position platform achieves accurate micro-position by the core of platform, piezoelectric ceramic actuator. It needs not only high positioning accuracy, but also high frequency response. In order to obtain the above function, how to design a piezoelectric actuator power, with high frequency response and low ripple, becomes a very important part in this platform.In this paper, comparing the theory of the PZT driver power in domestic and national, error magnify type and high voltage op-amp type is selected to design the high frequency response and low ripple power. The main contents are as follows:1. High-frequency response piezoelectric ceramics driver based on the error amplifier. To make the output displacement of piezoelectric ceramics has the quality of high-frequency response, the driver requires high current, high-voltage output characteristics, and so a driver of piezoelectric ceramics is designed and implemented by discrete components of the error amplifier. And four parallel output circuit is used in the part of the power amplifier in order to increase the drive current to achieve the rapid drive of piezoelectric ceramics. Experiment indicates the frequency response of the designed PZT power up to 1 kHz when working at Maximum voltage amplitude 120V), its highest frequency response is 2.4 kHz.2. Research on the static characteristics of piezoelectric driver. When drive power is at rated load (capacitive), the frequency response and ripple specifications are directly related to whether the experimental platform contains high frequency response and high precision. Through in-depth analysis of the causes of ripple, find out that the main factor affecting the ripple is the input offset voltage of error amplifier circuit in the prior to circuit. And by theoretical calculation the optimal value of the input offset voltage is obtained. Experiments show that, when working within its output voltage the ripple can be controlled within 5mV. In addition, by using the method of feedback zero compensation, the circuit stability is increased when driving capacitive loads. The correctness of the design is verified by simulation and experiments. 3. Control circuit of the Drives. Using FPGA as the main chip of the circuitry, it controls the DAC to complete signal generation. The Verilog language is used in the programming of the FPGA. The circuitry outputs sine wave, square wave, triangle wave and DC signal. On this basis, drive control system is developed. Labwindows software is used in the subject to complete the data acquisition card program design of PCI-1716. The design can achieve single-or dual-channel sampling, sample data preservation, sample signal waveform display, the signal frequency and amplitude display.