Servo Actuation Power Limiting via Downstream Voltage Feedback
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Solution Overview
Problem
Existing power limiting schemes in missile servo actuation systems are inefficient and inaccurate, as they rely on static current measurements and do not account for varying power demands, leading to potential damage from excessive power consumption and reduced system capability.
Innovation Solution
A method that determines a parameter downstream of the inverter, such as motor voltage or current, to calculate a limiting value applied by the controller, ensuring power remains within a defined supply limit, thereby reducing the number of components and using existing sensors, and compensates for variations in supply voltage to maintain accurate power control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If power limiting is implemented using static current measurements and nominal resistance values, then the system can limit power consumption, but the power estimation becomes inaccurate and system capability is reduced
Solution Approach 1:
The patent implements feedback by measuring the actual voltage downstream of the inverter and using this real-time measurement to calculate accurate power consumption. The controller continuously monitors the voltage parameter and adjusts the power limit accordingly, creating a closed-loop system that accurately reflects actual power consumption rather than relying on static estimates.
Solution Approach 2:
The patent changes the parameter used for power calculation from static nominal resistance values to dynamic voltage measurements. By measuring the actual voltage downstream of the inverter and using this variable parameter in power calculations, the system adapts to changing operating conditions and maintains accurate power estimation.
2Loss of energy
If power limiting schemes are applied upstream of the inverter, then power can be limited, but additional sensors and components are required increasing system complexity
Solution Approach 1:
The patent applies the self-service principle by using the inverter's existing downstream voltage measurement capability to enable power limiting functionality. The system uses measurements already taken for other control purposes (voltage downstream of inverter) and repurposes this data for power calculation, allowing the system to monitor and limit its own power consumption without external sensors or additional components.
Solution Approach 2:
The patent makes the existing voltage measurement system multi-functional by using the downstream voltage measurement not only for inverter control but also for accurate power consumption calculation. This universal use of the same measurement infrastructure eliminates the need for separate sensors, reducing system complexity while maintaining accurate power monitoring.
3Quantity of substance
If multiple missile units draw from the same passive battery source, then the system can operate with limited power sources, but voltage collapse occurs when one unit consumes excessive power
Solution Approach 1:
The patent implements feedback control by continuously measuring the actual voltage downstream of the inverter and using this information to calculate real-time power consumption. This feedback mechanism allows each missile unit to monitor its own power draw and adjust accordingly, preventing any single unit from causing voltage collapse that would affect other units sharing the same battery source.
Solution Approach 2:
The patent changes from static power estimation to dynamic parameter measurement by continuously monitoring the actual voltage downstream of the inverter. This dynamic approach allows the system to adapt to changing power consumption patterns and maintain reliable operation even when multiple units share a limited power source, preventing voltage collapse.
Data Source
AI summary
A method of actuating an article using a servo actuation system is disclosed. The system comprises a motor, a controller and an inverter. The controller comprises a position controller, a velocity controller and a current controller; the position controller outputs velocity demands to the velocity controller, the velocity controller outputs current demands to the current controller, and the current controller outputs voltage demands to the inverter. The inverter outputs inverted voltage demands to the motor. The method comprises: determining a parameter downstream of the inverter; calculating a limiting value from the parameter and a defined supply power limit; and applying the limiting value in the controller to ensure that the power drawn by the servo actuation system remains within the defined supply power limit.