Inductive Power Harvester With Saturation-Based Current Limiting
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Solution Overview
Problem
Existing power harvesters face challenges in maintaining a relatively fixed power output over a wide range of primary line currents, which can vary significantly, affecting efficiency and power delivery to grid monitoring equipment.
Innovation Solution
A power harvester design featuring an interleaved transformer core and a coil configuration, coupled with a rectifier and a transistor, includes a resistor to limit power delivery over a range of currents, ensuring constant power to a load through inductive coupling and saturation of the transformer core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a transformer with fixed efficiency and constant input-output power ratio is used, then the power delivery is automatically coupled to the demanded power, but the power output varies significantly with primary line currents instead of remaining relatively fixed
Solution Approach 1:
The patent applies dynamics by making the transformer core operate in saturation at high currents through the addition of a resistor in series with the secondary winding. This dynamic operation allows the core to transition between linear and saturated states based on current levels, enabling the system to maintain relatively fixed power output across a wide range of primary line currents while adapting to varying grid conditions
2Loss of energy
If the transformer core operates in linear region, then the transformation is efficient, but the power output varies with primary line currents instead of remaining constant
Solution Approach 1:
The patent changes the operating parameters of the transformer core by introducing a resistor that causes the core to enter saturation at high currents. This parameter change allows the system to maintain efficiency at low currents while limiting power output at high currents, achieving relatively fixed power delivery across varying current conditions
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 maintains a relatively constant power delivery to grid monitoring equipment over a large range of primary line currents, optimizing efficiency at low currents and managing power diversion for higher currents, thus ensuring reliable operation of sensors and associated equipment.
Implementation Method 1
The power harvester uses inductive transformation of electrical power. Inductive transformers taking advantage of electromagnetic phenomena as described by Maxwell's equations.
Implementation Method 2
The transformer core is driven into saturation to provide for limiting of the power over a range of currents within the current conductor
Data Source
AI summary
A power harvester having a current transformer configured to be inductively coupled to a current conductor and a circuit for delivering power to a load. The transformer core has two sections joined together and separable from one another at interleaved portions, allowing the transformer to be installed around the current conductor. The circuit includes a rectifier coupled to the transformer and a transistor coupled in series between the rectifier and a load. The transistor receives an output current from the rectifier and provides power to the load. A resistor is coupled to the transistor and the load, and the transistor and resistor provide for limiting of the power to the load over a wide range of the conductor line currents.