Bi-directional Hysteresis Control for Servo Actuator Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional servo controllers for gas and steam turbines become bulky due to the need for large heat sinks in linear drive circuitry, leading to reduced energy efficiency and increased temperature in control panels.
Innovation Solution
Implementing bi-directional hysteresis control to manage actuator drive current through switching amplifiers, which eliminate the need for heat sinks by operating in 'on' or 'off' states, reducing heat dissipation and allowing for more compact designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If linear buffers or linear amplifiers are used to provide drive current for actuators, then the actuator can be controlled with precise current, but bulky heat sinks are required to dissipate excess heat
Solution Approach 1:
The patent changes the operating parameters of the drive circuitry from linear operation to switching operation. By using pulse-width modulation (PWM) to switch the power transistors between fully on and fully off states, the circuit operates in a non-linear regime that dramatically reduces power dissipation while maintaining precise average current control through duty cycle adjustment.
Solution Approach 2:
The patent employs periodic switching action through PWM control, where the power transistors are rapidly switched on and off at a fixed frequency. This periodic action allows the average current to be precisely controlled by adjusting the duty cycle, while the switching nature minimizes the time the transistors spend in the high-dissipation linear region.
2Reliability
If linear amplifiers are used for excitation drive circuits, then AC excitation current can be provided for transducers, but bulky heat sinks are required
Solution Approach 1:
The patent transforms the excitation drive circuit from a linear amplifier to a switching amplifier that generates AC excitation current through PWM modulation. The switching action allows the circuit to deliver the required AC current to transducers like LVDTs and resolvers while operating in efficient on/off states that minimize heat generation.
Solution Approach 2:
The patent replaces the thermal management mechanism (heat sinks) with an electronic control mechanism (PWM switching). Instead of managing heat dissipation through large thermal mass, the system substitutes switching electronics that inherently generate less heat, thereby eliminating or dramatically reducing the need for heat sinks.
3Ease of operation
If conventional linear drive circuitry is used, then actuator control is achieved, but energy efficiency is reduced and heat dissipation increases
Solution Approach 1:
The patent changes the operational parameters from continuous linear control to discontinuous switching control. By modulating the duty cycle of PWM signals, the system maintains precise actuator control while operating the power transistors in highly efficient switching states, reducing resistive losses and improving overall energy efficiency.
4Adaptability or versatility
If multiple valves with actuators and LVDTs are controlled, then comprehensive turbine control is achieved, but the servo controller becomes excessively bulky
Solution Approach 1:
The patent implements a universal switching amplifier architecture that can drive multiple actuators and excitation circuits using a single or few multi-functional power stages. By using PWM control that can be programmed to output different waveforms and frequencies, the same hardware platform can control various turbine components, eliminating the need for separate linear amplifier circuits for each actuator.
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
This approach enhances efficiency, reduces heat dissipation, and minimizes the size of heat sinks, resulting in a more compact and efficient servo actuator control system.
Implementation Method 1
controlling actuator drive current using bi-directional hysteresis control
Data Source
AI summary
Certain embodiments of the invention may include systems, methods, and apparatus for controlling actuator drive current. According to an example embodiment of the invention, a method is provided for controlling actuator drive current. The method may include receiving a reference signal, determining a feedback signal based at least in part on the drive current, determining a conditioned feedback signal based at least in part on the feedback signal, comparing the reference signal to the conditioned feedback signal, and controlling the drive current based on the comparison of the reference signal and the conditioned feedback signal. Certain embodiments of the method may include manipulating one or more devices to establish at least one positive current path and at least one negative current path through an actuator via hysteresis control.