Inductive Power Transfer Phase Compensation Under Relative Movement
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Solution Overview
Problem
Inductive energy transmission in transport systems, such as linear and planar motors, faces challenges due to relative movements between primary and secondary parts, leading to shifts in resonance frequencies, increased reactive power from leakage inductance, and inefficiencies in active power transmission, which existing methods fail to adequately address, especially concerning hardware requirements and adaptability.
Innovation Solution
A system that uses a secondary-side compensation current to induce a compensation voltage in the primary coil, altering the phase shift between voltage and current, thereby increasing active power transmission without additional primary-side storage elements, and reducing reliance on primary-side reactive power compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If resonant coupling is applied to increase magnetic coupling and efficiency, then active power transmission is improved, but the system becomes sensitive to resonance frequency shifts caused by relative movements, reducing reliability
Solution Approach 1:
The patent changes the operating parameter from resonance frequency coupling to direct frequency coupling. The supply frequency is set equal to a predetermined frequency corresponding to the leakage inductance of the transmitting coil, rather than tuning to a resonance frequency. This eliminates sensitivity to resonance frequency shifts caused by relative movements between primary and secondary parts, while still achieving efficient active power transmission through optimized frequency selection based on leakage inductance characteristics.
2Loss of energy
If primary-side capacitive compensation is used to compensate for leakage inductance, then reactive power is reduced, but hardware complexity and device size increase
Solution Approach 1:
The patent extracts and eliminates the need for primary-side capacitive compensation hardware. Instead of adding capacitors to compensate for leakage inductance on the primary side, the invention accepts the leakage inductance as inherent system characteristics and compensates for its effects through frequency selection and secondary-side reactive power management. This removes the additional hardware components while maintaining system efficiency.
Solution Approach 2:
The system uses the secondary side to provide its own reactive power compensation. The secondary-side converter handles the reactive power requirements locally, eliminating the need for separate primary-side compensation components. The primary side focuses on active power transmission while the secondary side manages its own reactive power needs through the converter circuitry.
3Power
If supply voltage is increased to overcome feed limitations, then available electrical power increases, but physical limits of power electronic devices are exceeded
Solution Approach 1:
The patent changes the approach to increasing power transmission capability by optimizing frequency selection instead of increasing voltage. The supply frequency is specifically tuned to match the predetermined frequency corresponding to the transmitting coil's leakage inductance, which maximizes the active power transmission efficiency within the existing voltage and current limits of the power electronic devices. This allows full utilization of available device capabilities without exceeding their physical limits.
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 approach enhances active power transmission by up to several thousand percent, reduces hardware requirements, and improves adaptability to changing conditions, specifically by using a secondary-side compensation unit to modify phase shifts and optimize energy transfer.
Implementation Method 1
an electrical primary current is fed from a supply unit into a transmitting coil arranged on the primary part in order to create a first alternating magnetic field for energy transmission, whereby an electrical AC voltage is induced in a receiving coil arranged on the secondary part
Implementation Method 2
A system that uses a secondary-side compensation current to induce a compensation voltage in the primary coil, altering the phase shift between voltage and current, thereby increasing active power transmission
Data Source
AI summary
A method for inductive energy transmission between a primary part and a secondary part, wherein a primary current is introduced into a transmitting coil arranged on the primary part in order to create a first magnetic field which induces an electrical AC voltage in a receiving coil arranged on the secondary part, which electrical AC voltage causes an electrical secondary current at the secondary part and thus a power flow to at least one load connected to the receiving coil, which power flow comprises an uncompensated active power, it is provided that a compensation unit introduces a compensation current into a secondary-side coil, which compensation current generates a second magnetic field which is superimposed on the first magnetic field and induces a compensation voltage in the transmitting coil. The compensation voltage changes the phase shift between the primary voltage that drops across the transmitting coil and the primary current flowing through the transmitting coil in such a way that the transmitted active power is increased.