Full-Bridge Reactive Power Compensation for Inductive Position Sensors
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Solution Overview
Problem
Existing methods for compensating reactive power consumed by inductive position sensors in magnetic bearings are limited by fixed voltage capacitors, leading to restricted sensor compatibility and introduce time delays due to sensors and filters, necessitating a more adaptable and efficient compensation method.
Innovation Solution
A method and system that determines the phase shift between supply voltage and current to generate a compensation current in phase with the supply voltage using a full bridge converter, controlled by a control system with multiple loops to adjust amplitude and phase, employing logic circuits and energy storage devices to compensate reactive power without altering circuit element values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed voltage capacitors are used in the compensation device, then the circuit structure is simple, but the range of sensors that will work with the device is limited
Solution Approach 1:
The patent implements dynamic voltage adjustment for the capacitors in the compensation device. The capacitor voltage is no longer fixed but can be dynamically adjusted to match different sensor requirements. This is achieved through a control system that adjusts the capacitor voltage based on the specific sensor being compensated, thereby expanding sensor compatibility without requiring complete circuit redesign for each sensor type.
Solution Approach 2:
The patent changes the voltage parameter of the capacitors from a fixed value to an adjustable parameter. By allowing the capacitor voltage to vary, the system can adapt to different sensor characteristics and cable configurations. This parameter change enables the same hardware circuit to work with a broader range of sensors while maintaining structural simplicity.
2Reliability
If sensors and filters are used to determine reactive current, then the reactive power can be compensated, but a time delay is introduced
Solution Approach 1:
The patent replaces traditional mechanical/electronic filtering methods with a calculation-based approach. Instead of using physical filters to determine reactive current, the system calculates the reactive current component through mathematical operations on the measured current signal. This substitution eliminates the time delay inherent in filter-based methods while maintaining the accuracy needed for reliable compensation.
Solution Approach 2:
The patent implements a feedback control mechanism where the compensation current is continuously adjusted based on the phase difference between the sensor current and the compensation current. The control system monitors the compensation effect in real-time and adjusts the injected current accordingly, achieving accurate compensation without relying on delayed filter responses.
3Adaptability or versatility
If the capacitor voltage is fixed, then the control system is simple, but the adaptability to different sensor types is reduced
Solution Approach 1:
The patent makes the capacitor voltage dynamic rather than fixed. The control system adjusts the capacitor voltage according to the specific sensor type and configuration being compensated. This dynamic adjustment capability allows the same control system to handle multiple sensor types effectively, improving adaptability while the control algorithms manage the increased complexity.
Solution Approach 2:
The patent designs the control system to perform multiple functions: it not only controls the compensation current but also adjusts the capacitor voltage to match different sensor requirements. This multi-functional approach allows a single control system to adapt to various sensor types and cable configurations, achieving universality without requiring separate compensation devices for each sensor type.
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 method effectively compensates reactive power for various sensor/cable combinations, is robust to time delays, and adapts to different types of inductive position sensors, ensuring efficient power factor correction.
Implementation Method 1
The full bridge converter is controlled according to a control signal to generate a compensation current in phase with the supply voltage
Implementation Method 2
determining a voltage reference value for an energy storage device from the amplitude of the control signal and a duty cycle reference value
Data Source
AI summary
A control system (15) for controlling a full bridge converter to compensate the reactive power consumed by an inductive position sensor for a rotor of an electrical machine supported by at least one active magnetic bearing is proposed. The inductive position sensor is supplied by an alternating current source. The control system (15) includes a phase shift determining means (26) to determine a phase shift (SP) between a supply voltage (VS) and a supply current (IS) delivered by the source. A first control loop (22) controls the amplitude (Ac) of a control signal (SC) from the phase shift (SP). A second control loop (23) controls the phase of the control signal (SC). A third control loop (24) controls a voltage reference (VR). A controlling means (25) controls a full bridge converter according to the control signal (SC).