JPS6126272A - Driving device for reactive load - Google Patents

Abstract

PURPOSE:To enable the efficient utilization of power by a method wherein the reactive power generated by reactive load is recollected and re-utilized. CONSTITUTION:When a switch S1 turns on, a current I flows through an inductance L, a piezoelement C1 discharges. Next, when the switch S1 is turned off and a switch S2 on, a capacitor C2 is set in charging and turns off the switch S2 at the time when the current I becomes 0. Then, the capacitor C2 is charged into the energy lost in the element C1 and the voltage energy for next impressing by turning on a switch S3. The element C1 is started to be charged by turning the switch S2 on, the switch S2 off at the time when the voltage V2 of the capacitor C2 becomes 0, and S1 on, resulting in the drive of the piezoelement. Then, the switch S1 is turned off at the time when the current I becomes 0. After a necessary time is passed, the switch S1 is turned on and the above-mentioned process is repeated. This manner minimizes the energy loss and yields the driving device of high efficiency for capacitive load.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a reactive load drive device that drives a reactive load such as a piezo element.

<Prior Art> The input impedance of an electrostrictive element using a piezo or the like is close to pure capacitance, and driving these elements results in almost no reactive power. Conventionally, this power turned into heat in the output transistor of the drive device, resulting in low efficiency, large device size, and increased cost.

<Objective> In view of the above-mentioned shortcomings of the prior art, it is an object of the present invention to provide a highly efficient reactive load drive device.

<Embodiment> FIG. 1 is a drive circuit diagram of an embodiment of the present invention, and FIG. 2 is an operation timing diagram of each part of FIG. 1.

In this embodiment, a case where the load is capacitive will be described.

In the figure, 01 is a piezo element used in an inkjet head as a reactive load, and DR is a drive circuit that drives the piezo element C1.

Ll is an inductance, and C2 is a capacitor, both of which constitute a recovery means. R is resistance, E is variable DC power supply, S
l, 82.83 are switches.

First, the piezo elements C1Vcv are charged with a voltage of sl, s2. All s3 are turned off.

When the switch S1 is turned on at time t1 in FIG. 2, a current I flows through the inductance L, C1 is discharged, and the voltage V of C1 is
When 1 becomes 0, the electric current is at its maximum.

When the switch S1 is turned off and C2 is turned on at this time t2, the capacitor C2 is charged, and at the time when ■ becomes 0, the capacitor 82 is turned off. Next, 83 is turned off, and 02 is charged with the energy lost in the piezo element C1 and the voltage energy to be applied next (t4 to t5). 82 at t6
is turned on, and at time t7 when the voltage of C2 becomes OK, 82
is turned off, Sl is turned on, charging of the piezo element CIK is started, the piezo element is driven, and Sl is turned off at time t8 when the electric current reaches zero. Then, after the necessary time has elapsed, 81 is turned on at time t9, and the process of 11.19 is repeated.

The electrostatic energy stored in CIK in this way is recovered as electrostatic energy in C2 via the magnetic energy of Ll, and the amount lost in this process can be used to realize the next drive port.

In FIG. 2, 0 indicates the off state of the switch, and 1 indicates the on state of the switch. Turning on switches 81 to S3,
Off can be controlled by a known timing signal generator.

Effects> As described above, according to the present invention, it becomes possible to recover and reuse the reactive power generated by the reactive load, thereby realizing efficient use of power and contributing to power saving. Furthermore, it can contribute to making the power source smaller and lighter.

[Brief explanation of drawings]

FIG. 1 is a drive circuit diagram of this embodiment, and FIG. 2 shows voltage and current waveforms of each part of FIG. 1 and switch S1. It is a figure which shows the state of C2 degree C3. In the figure, 01 is a piezo element as a reactive load, DR is a drive circuit, Ll and C2 are inductances and capacitors constituting recovery means, and sl, C2 and C3 are switches, respectively.

Claims (1)

[Claims] 1. A driving device for a reactive load, comprising a reactive load having a reactance component, a driving circuit for driving the reactive load, and a recovery means for recovering reactive power generated in the reactive load to the driving circuit.