Single-Phase ICPT Power Supply Using LCL Filter
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Inductively Coupled Power Transfer (ICPT) systems require expensive and bulky DC energy storage components, making them inefficient and costly, especially when dealing with varying loads and requiring complex power factor control, which is unsuitable for single-phase power supplies.
Innovation Solution
A single-phase ICPT power supply using a transformer with leakage inductance, a capacitive element, and a conductive path inductance to form an LCL filter, along with a controller to manage power flow and duty ratio, eliminating DC energy storage components and allowing for efficient power transfer with varying track currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional 3-phase power supply with DC energy storage components is used, then constant current output is achieved, but the system becomes bulky, expensive, and complex
Solution Approach 1:
The patent removes the DC energy storage components (capacitors and inductors) from the power supply system entirely. Instead of using conventional rectification and inversion stages with large DC link components, the invention directly converts single-phase AC to the required output using only reactive components (LCL filter), eliminating the bulky and expensive DC storage elements while maintaining constant current output capability
Solution Approach 2:
The patent changes the operating parameters by using single-phase AC input instead of 3-phase, and operates the LCL filter at resonant frequency. This allows the system to achieve constant current output without DC energy storage components by exploiting the resonant characteristics of the LCL filter formed by the transformer leakage inductance, capacitive element, and conductive path inductance
2Use of energy by moving object
If DC energy storage components are used, then power factor correction is achieved, but the system size and weight increase significantly
Solution Approach 1:
The patent extracts and removes the heavy DC energy storage components from the system. Power factor correction is achieved not through large DC capacitors and inductors, but through the resonant operation of the LCL filter with much smaller reactive components, dramatically reducing system weight while maintaining excellent power factor
Solution Approach 2:
The patent uses the reactive components of the LCL filter (transformer leakage inductance, capacitive element, and conductive path inductance) to replicate the power factor correction function traditionally provided by large DC energy storage components, achieving the same electrical performance with minimal mass
3Weight of stationary object
If single-phase power supply is used, then system size is reduced, but power factor control becomes complex for varying loads
Solution Approach 1:
The patent makes the power supply system self-regulating by operating the LCL filter at its resonant frequency. The system automatically adapts to varying loads without complex control circuitry because the resonant operation inherently maintains power factor correction and constant current output, eliminating the need for additional active control components
Solution Approach 2:
The patent utilizes periodic resonant oscillations of the LCL filter at a specific frequency to achieve automatic power factor correction. By operating at this resonant frequency, the system naturally maintains the required electrical characteristics across varying load conditions without needing complex real-time control algorithms
4Productivity
If high frequency operation is used, then power transfer efficiency improves, but track inductance makes current establishment difficult
Solution Approach 1:
The patent applies resonant vibration principles to the electrical system by operating the LCL filter at its natural resonant frequency. This resonant operation allows efficient power transfer at high frequencies while reducing the voltage required to establish track current, as the resonant oscillation naturally builds up current in the inductive track
Solution Approach 2:
The patent exploits the phase relationship changes that occur at resonant frequency in the LCL filter. By operating at this specific frequency, the system achieves a phase condition where the inductive and capacitive reactances balance, enabling efficient high-frequency power transfer with reduced voltage requirements for current establishment
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 achieves high input power factor and reduced size and weight, enabling continuous power supply to loads with fluctuating track currents, improving efficiency and reducing operational costs by distributing power supplies across the system.
Implementation Method 1
a transformer and a capacitive element wherein the leakage inductance of the transformer, the capacitance of the capacitive element and the inductance of the conductive path provide an LCL filter
Implementation Method 2
Pick-up coils along the track intercept some of the magnetic field from the track
Data Source
Figure 1~2
Figure 3~4
Figure 5~6B
AI summary
An ICPT system has a single phase power supply which energises a conductive path (13) and has an inverter (5) to provide an alternating current at an operating frequency greater than the single phase utility supply frequency in the conductive path. The inverter modulates the amplitude of the alternating current with respect to the utility supply frequency such that the amplitude of the alternating current varies. The pick-up has an energy storage element (26) to provide a continuous supply of power to a load (27) irrespective of the varying amplitude of the alternating current in the conductive path.