Planar Transformer Compensation Circuit for Common Mode Noise
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Solution Overview
Problem
Planar transformers experience common mode noise due to capacitive coupling between primary and secondary windings, which reduces performance and requires additional components or increased size to mitigate, leading to inefficiencies and higher costs.
Innovation Solution
A compensating arrangement with a coupling capacitor and conductor provides an AC link between the windings, inducing a voltage that counteracts parasitic currents caused by capacitive coupling, effectively reducing common mode noise without increasing component count or size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If additional filtering components are added to reduce common mode noise, then common mode noise is reduced, but device complexity and cost increase
Solution Approach 1:
The patent utilizes the parasitic capacitance between primary and secondary windings, which normally generates harmful common mode noise, to create a beneficial effect. By connecting a capacitor across the secondary winding terminals, the parasitic capacitance becomes part of a compensating circuit that generates a counter-phase current to cancel the common mode noise current, converting the harmful parasitic effect into a useful noise cancellation mechanism.
Solution Approach 2:
The patent introduces a compensating capacitor as an intermediary element that mediates between the parasitic capacitance and the secondary winding. This capacitor creates an AC link that allows induced voltage to generate a compensating current, serving as a mediator that transforms the harmful parasitic coupling into a beneficial counteracting force without requiring complex external filtering circuits.
2Object-affected harmful factors
If additional filtering components are added to reduce common mode noise, then common mode noise is reduced, but manufacturing cost increases
Solution Approach 1:
The invention converts the harmful parasitic capacitance into a beneficial noise cancellation mechanism, eliminating the need for expensive external common mode filters. The compensating capacitor can be implemented using standard capacitor values, significantly reducing component costs compared to traditional filtering solutions.
Solution Approach 2:
The transformer arrangement becomes self-correcting by utilizing its own parasitic capacitance to generate the compensating current. The system automatically cancels its own common mode noise without requiring external active filtering components, reducing both component count and manufacturing complexity.
3Object-affected harmful factors
If transformer core volume is increased to reduce capacitive coupling, then common mode noise is reduced, but device size and cost increase
Solution Approach 1:
Instead of trying to eliminate parasitic capacitance by increasing transformer size, the patent embraces the parasitic capacitance and converts it into a useful resource for noise cancellation. This approach allows maintaining compact transformer dimensions while achieving effective common mode noise reduction through the compensating circuit.
4Volume of stationary object
If winding proximity is increased to reduce size, then device size is reduced, but common mode noise increases
Solution Approach 1:
The patent allows close winding proximity for compact size by converting the resulting parasitic capacitance into a beneficial noise cancellation mechanism. The compensating capacitor transforms the harmful effect of close coupling into a useful counter-phase current that actively cancels common mode noise, enabling compact designs without sacrificing noise performance.
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 solution significantly reduces common mode noise while maintaining efficiency and reducing costs by allowing full utilization of the transformer core volume and avoiding external filtering circuits, with the compensating current precisely adjusting to counteract parasitic capacitance effects.
Implementation Method 1
a change of a magnetic flux through the primary winding and the secondary winding induces a voltage in the compensating arrangement
Data Source
AI summary
A transformer arrangement comprises a primary winding and a secondary winding, which are magnetically coupled. The transformer arrangement also comprises a compensating arrangement, which is circuited to provide a link between a terminal of the primary winding and a terminal of the secondary winding. The compensating arrangement is configured such that a change of a magnetic flux through the primary winding and the secondary winding induces a voltage in the compensating arrangement. The compensating arrangement comprises at least one coupling capacitor configured to block a DC current and to pass a current caused by the induced voltage. The compensating arrangement is configured to at least partially compensate a current that is caused by an inter-winding capacitance between the primary winding and the secondary winding using the current caused by the induced voltage.