Power Amplifier Variable Duty Cycle Control for Active Magnetic Bearings
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Solution Overview
Problem
Existing power amplifiers for active magnetic bearings suffer from significant power losses, output voltage ripple, and output current ripple due to eddy currents in inductive loads, which generate excessive heat and inefficiency.
Innovation Solution
A power system comprising semiconductor devices and a controller that operates semiconductor switches to manage output current, using a DC power source and capacitors to reduce ripple, and a current sensor to adjust the current flow, thereby minimizing AC components in output voltage and current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If H-bridge based power amplifiers operate switches with a 50% duty cycle, then the power amplifier can control output current, but significant AC component is generated in output voltage and current causing power losses
Solution Approach 1:
The patent applies dynamics by making the duty cycle variable rather than fixed at 50%. The controller dynamically adjusts the duty cycle of semiconductor switches based on the operating conditions and current requirements, allowing the power amplifier to maintain effective current control while minimizing AC components and reducing power losses in inductive loads.
2Power
If H-bridge based power amplifiers operate switches with a 50% duty cycle, then the power amplifier can control output current, but excessive heat dissipation occurs due to eddy currents in inductive loads
Solution Approach 1:
The patent applies dynamics by making the duty cycle variable rather than fixed at 50%. The controller dynamically adjusts the duty cycle of semiconductor switches based on the operating conditions and current requirements, allowing the power amplifier to maintain effective current control while minimizing AC components and reducing power losses in inductive loads.
3Loss of energy
If semiconductor switches are operated with variable duty cycle, then power losses and ripple are reduced, but device complexity increases due to controller requirements
Solution Approach 1:
The patent applies feedback by incorporating a current sensor that measures the actual output current and feeds this information back to the controller. The controller uses this feedback to continuously adjust the duty cycle of semiconductor switches, enabling automatic optimization of power losses and ripple reduction without requiring complex external control systems.
4Loss of energy
If current sensor and controller are added to adjust duty cycle, then output current ripple and eddy currents are minimized, but manufacturing cost increases
Solution Approach 1:
The patent applies feedback by incorporating a current sensor that measures the actual output current and feeds this information back to the controller. The controller uses this feedback to continuously adjust the duty cycle of semiconductor switches, enabling automatic optimization of power losses and ripple reduction without requiring complex external control systems.
Data Source
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AI summary
Unique systems, methods, techniques and apparatuses of power amplifiers are disclosed. One exemplary embodiment is a power system for an active magnetic bearing including at least one power amplifier. Each power amplifier includes a first semiconductor device including a first node coupled to a neutral point node and a second node, a second output node coupled to the neutral point node, a second semiconductor device including a first node coupled to the second node of the first semiconductor device and a second node coupled to a first output node, a third semiconductor device including a first node coupled to a first DC bus node and a second node coupled to the first output node, and a fourth semiconductor device including a first node coupled to a second DC bus node and a second node coupled to the second node of the first semiconductor device.