Instantaneous Power Determination in Induction Heating Inverters
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Solution Overview
Problem
Existing induction heating systems can only determine the average power delivered to a container, lacking the capability to continuously monitor and adjust instantaneous power, which is essential for precise temperature control and user-setpoint power management.
Innovation Solution
A method and device that measure peak currents in the switch and freewheel diode within the inverter power supply device, using a bijective function to calculate instantaneous power based on these values, duty cycle, and control period, allowing for real-time power determination and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If average power measurement is used, then the system is simple to implement, but instantaneous power control precision deteriorates
Solution Approach 1:
The patent segments the power measurement into two distinct components: peak current measurement (capturing maximum current amplitude) and duty cycle measurement (capturing switching ratio). By measuring these separate parameters and combining them through a bijective function, the system achieves instantaneous power determination without requiring complex continuous power monitoring circuitry, thus resolving the contradiction between simplicity and precision.
2Measurement precision
If instantaneous power measurement is implemented, then power control precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces a bijective function as an intermediary mathematical relationship that connects easily measurable parameters (peak current and duty cycle) to the desired instantaneous power value. This intermediary function allows the system to derive precise power information from simple measurements, avoiding the need for complex direct power measurement hardware while maintaining high measurement precision.
3Measurement precision
If continuous power monitoring is implemented, then temperature control precision is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic measurement of peak current and duty cycle at each switching cycle of the power supply device. This periodic sampling approach provides continuous monitoring capability for precise temperature control while consuming minimal energy, as the measurements are taken only at necessary intervals rather than requiring continuous high-power monitoring circuitry operating throughout the heating process.
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
Enables permanent knowledge of instantaneous power delivery, facilitating optimal control loop adjustments to maintain user-setpoint power, improving heating efficiency and precision.
Implementation Method 1
the field of induction heating, and in particular induction hobs comprising one or more induction hearths suitable for heating a container placed on a hearth
Data Source
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AI summary
The method involves measuring peak current (It) circulating in an insulated gate bipolar transistor (IGBT) switch. Peak current (Id) circulating in a free wheel diode (D) is measured. Instantaneous power delivered by an induction unit associated with the container to be heated is determined by a bijective function associating the instantaneous power with a quadruple of values of the peak currents, cyclic ratio (delta) of the switch and control period (T). The peak current of the switch is equal to the current circulating in the switch at the end of a conduction period of the switch. An independent claim is also included for a device for determining instantaneous power delivered by an induction unit associated with a container to be heated, comprising a measurement unit.