Patent WO-2020117097-A2 (WO)
Title: Device for powering a piezoelectric stepper motor (variant embodiments)
Inventor: KUZNETSOV ANDREY LEONIDOVICH
Filed: 2019-11-27
Abstract: The invention relates to electrical engineering and can be used for powering piezoelectric stepper motors used in everyday life, transportation and industry to actuate different mechanisms and pumps. The present device comprises three parallel-connected modules for generating pulses which impinge on the plates of a piezo actuator P n  of the respective module n (n=1,2,3). Each module n is connected by its output terminals to a direct current power supply (hereinafter DC) having a storage capacitor C1 connected thereto, and is formed by two half-bridges, the midpoints of which are connected by a storage choke L n , and a device for controlling the electronic switches of the half-bridges. In a first embodiment, the modules are identical. The first half-bridge consists of series-connected controllable electronic switches К 1n  and К 2n , and the second half-bridge consists of series-connected controllable electronic switches К 3n  and К 4n  (hereinafter switches). Said switches have diodes connected in parallel thereto, as follows: switch К1n to diode D 1n ; switch К 2n  to diode D 2n ; switch К 3n  to diode D 3n ; and switch К 4n  to diode D 4n . In a second embodiment, the middle module of the above-described device additionally contains a third half-bridge connected in parallel to the first half-bridge. The third half-bridge is formed by a diode D 52  and a switch К 52  connected in series. The cathode of diode D52 is connected to the positive terminal of DC, and the anode of diode D 52  is connected to the input of switch К 52 . The output of switch К 52  is connected to the negative terminal of DC. A choke L 22  is connected in between the midpoints of the third half-bridge and the second half-bridge. In a third embodiment, all three modules are identical. The first half-bridge of each module consists of series-connected switches К 1n  and К 2n . The second half-bridge is formed by a switch К3n and a diode D4n connected in series. Each of said switches has a diode connected in parallel thereto, as follows: switch К1n to diode D1n; switch К2n to diode D2n; switch К 3n  to diode D 3n . The input of switch К 1n  is connected to the positive terminal of DC. The output of switch К 2n  is connected to the negative terminal of DC. The input of switch К 3n  is connected to a positive contact of a piezo actuator P n , the anode of diode D 4n  is connected to a negative contact of the piezo actuator P n  and to the negative terminal of DC. In a fourth embodiment, a third half-bridge is additionally connected in parallel to the first half-bridge of the second module. The third half-bridge is formed by a diode D 52  and a switch К 52  connected in series. The cathode of diode D 52  is connected to the positive terminal of DC, the anode of diode D 52  is connected to the input of switch К 52 . The output of switch К 52  is connected to the negative terminal of DC. The midpoints of the third half-bridge and the second half-bridge are connected by a choke L 22 , the inductance of which is greater than the inductance of L 2 . The design of the device is intended to generate electrical oscillations on the plates of each piezo actuator (P) in different phases of each step of a piezoelectric motor, thus allowing the working member of the piezoelectric stepper motor to perform translational or rotational movement with high energy efficiency. High energy efficiency is achieved by storing the energy released during the discharging of the piezo actuators and returning this energy for the subsequent charging of a piezo actuator in the next step of the motor.