H-Bridge Circuit for Piezo Actuator Charge Recovery
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Solution Overview
Problem
Existing bridge circuits for driving piezoelectric actuators suffer from high electrical losses during charge reversal, requiring additional components and complex switching converters, which increase power consumption and occupy significant space, especially in low-power applications.
Innovation Solution
A novel H-bridge circuit with a shunt arm incorporating a capacitance, inductance, and a third partial inductance, allowing for efficient charge recovery and voltage amplification or attenuation without additional components, using a coupled inductor to minimize energy losses and enable bipolar operation with unipolar power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional H-bridge circuits with series inductance are used for charge reversal, then piezoelectric actuator can be driven, but electrical losses are high and additional components are required
Solution Approach 1:
The patent converts the harmful electrical losses during charge reversal into beneficial magnetic field energy storage. By using an inductor in the shunt arm, the energy that would normally be dissipated as heat is instead stored in the magnetic field and reused during the next charge cycle, thereby reducing overall energy losses.
Solution Approach 2:
The patent merges the functions of charge reversal and energy storage into a single integrated circuit structure. The inductor in the shunt arm simultaneously enables charge reversal of the piezoelectric actuator and stores magnetic field energy, eliminating the need for separate energy storage components and reducing circuit complexity.
2Loss of energy
If additional components and switching converters are added to reduce losses, then energy efficiency improves, but device size and complexity increase
Solution Approach 1:
The inductor in the shunt arm performs multiple functions simultaneously: it enables charge reversal of the piezoelectric actuator, stores magnetic field energy for reuse, and acts as an energy recovery mechanism. This multi-functionality eliminates the need for additional separate components, reducing both power consumption and circuit board space.
Solution Approach 2:
The circuit uses its own inductor to recover and reuse energy internally during operation. The magnetic field energy stored in the inductor during one phase is automatically reused during the next charge cycle, creating a self-sustaining energy recovery mechanism that reduces overall power consumption without external intervention.
3Device complexity
If conventional circuits are used, then simple structure is maintained, but charge reversal causes high energy loss
Solution Approach 1:
The patent converts the harmful energy loss during charge reversal into beneficial magnetic field energy. The inductor captures the energy that would normally be dissipated and stores it in its magnetic field, which is then reused during subsequent charge cycles, transforming waste energy into useful energy.
Solution Approach 2:
The patent changes the electrical parameters of the circuit by introducing an inductor, which alters the energy dynamics. The inductor's inductance parameter enables energy storage in magnetic field form, fundamentally changing how energy is handled during charge reversal from dissipative to regenerative.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves low-loss periodic charge reversal of piezoelectric actuators, reducing energy consumption and component count, allowing for precise control of mechanical forces and expanded application range in both resonant and non-resonant systems with reduced complexity and size.
Implementation Method 1
maintaining a magnetic field energy in the inductor by commutating
Implementation Method 2
A piezo actuator can deform when an electrical voltage is applied to the piezo actuator. In particular, the piezo actuator can perform a change in length.
Implementation Method 3
an inductor that has a first partial inductance and a second partial inductance that is inductively coupled to the first partial inductance
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a bridge circuit (104) for controlling a piezo actuator (102), which is configured as an H-bridge consisting of four switches (112, 116, 120, 122) and with a capacitor (124) and an inductor (126) in the cross branch (106). The inductor has a first partial inductance (128) and a second partial inductance (130) inductively coupled to it. One terminal of the first partial inductance is connected to a terminal of the capacitor. The second partial inductance is connected via a fifth switch (132) to a first contact of the interface (131) to the piezo actuator. The first contact of the interface is further connected to the cross branch via a sixth switch (134).