Induction Coil Frequency and Voltage Control for Abrupt Load Changes
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Solution Overview
Problem
Induction coils used in induction hobs face challenges in maintaining efficient power transmission when there are abrupt load changes or rapid movement of electrical consumers, leading to instability and potential damage due to changes in transformer-style coupling and electrical load.
Innovation Solution
The method involves using control means with two manipulated variables - operating frequency and voltage - to adjust primary power, employing a transfer function with local peaks to maintain optimal coupling, and dynamic current limiting to protect the system from sudden changes, ensuring efficient power transmission and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the induction coil operates with fixed frequency and voltage to maintain simple control, then the control system remains simple, but the system becomes unstable during abrupt load changes or rapid movement of electrical consumers
Solution Approach 1:
The control system dynamically adjusts operating frequency and voltage based on real-time coupling conditions and load changes. The system transitions from static fixed parameters to dynamic variable parameters, allowing adaptation to abrupt load changes and consumer movement while maintaining stability.
Solution Approach 2:
The control means continuously monitor the coupling between induction coil and receiver coil, and adjust frequency and voltage accordingly. This feedback mechanism detects changes in load conditions and modifies operating parameters to maintain optimal power transmission and system stability.
2Power
If the system uses maximum power transmission to meet high power demands, then the power supply capability is sufficient, but the system becomes vulnerable to damage from sudden load changes
Solution Approach 1:
The control system applies preliminary protective actions by monitoring coupling conditions and preemptively adjusting power levels before harmful current spikes can occur. When detecting rapid consumer movement or load changes, the system reduces power transmission in advance to prevent damage.
Solution Approach 2:
The system dynamically modulates power transmission levels based on real-time coupling conditions. Rather than maintaining maximum fixed power, the system adapts power output to match actual transmission efficiency, providing both high power capability when needed and protection when coupling deteriorates.
3Loss of energy
If the operating frequency is kept constant to simplify the control mechanism, then the control mechanism remains simple, but the coupling efficiency deteriorates during consumer movement
Solution Approach 1:
The system changes the operating frequency parameter in response to coupling conditions and consumer position. By adjusting frequency rather than keeping it fixed, the system maintains optimal coupling efficiency throughout consumer movement, reducing energy losses without requiring complex mechanical adjustments.
4Power
If the voltage applied to the primary-side resonant circuit is increased to boost power transmission, then the power transmission improves, but the risk of excessive current and component damage increases
Solution Approach 1:
The control system monitors current levels and coupling conditions, and adjusts applied voltage accordingly. When coupling efficiency is low or load conditions change rapidly, the system reduces voltage to prevent excessive current and component damage. When coupling is optimal, voltage is increased to maximize power transmission.
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 allows for robust operation of electrical consumers on induction hobs, even with abrupt load changes or movement, by adjusting primary power to match desired secondary power, reducing losses, and protecting circuit components from excessive current.
Implementation Method 1
a current in the induction coil induces a voltage in the receiver coil, which in turn causes a flow of current, as a result of which a secondary power is generated
Implementation Method 2
the induction coil forms a primary-side resonant circuit with a capacitance connected in series
Data Source
AI summary
A method for controlling an induction coil on an induction hob involves a power generation for a primary power on the induction coil for power transmission to an electrical consumer put onto a cover above the induction coil, which consumer has a receiver coil and an electrical load connected thereto, being adjusted. The induction coil forms a primary-side resonant circuit with a capacitance connected in series, and the induction coil and the receiver coil are coupled in the style of a transformer such that a current in the induction coil induces a voltage in the receiver coil with a flow of current and generation of the secondary power in the load of the electrical consumer. The control means can attempt to adjust the desired secondary power to a steady state using maximum modulation of the voltage effectively applied to the primary-side resonant circuit, as second manipulated variable. The primary power is decreased in a first step by virtue of the voltage effectively applied to the primary-side resonant circuit, as second manipulated variable, being decreased before the operating frequency as first manipulated variable is increased in a second, subsequent step.