Induction Heating Booster Circuit Shutdown Sequence
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Solution Overview
Problem
Conventional induction heating apparatuses face issues with excessive voltage boosting in booster and power factor correction circuits when heating stops, leading to potential element destruction due to sudden changes in load impedance.
Innovation Solution
The induction heating apparatus incorporates a boosting function unit with a choke coil and switching element, an inverter circuit, and a boosting control unit that controls the switching element to prevent excessive voltage boosting by stopping the boosting operation before the inverter circuit, ensuring a stable output voltage and safe shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the boosting operation is stopped simultaneously with the inverter circuit operation, then the shutdown process is simple and fast, but the load impedance changes suddenly causing excessive voltage boosting that may destroy circuit elements
Solution Approach 1:
The patent applies preliminary action by stopping the boosting operation before stopping the inverter circuit operation. This sequential shutdown approach prepares the system in advance by gradually reducing the boosting function while the inverter circuit continues to operate, preventing sudden load impedance changes and excessive voltage boosting that could damage circuit elements.
2Speed
If the inverter circuit is stopped first, then the heating operation stops immediately, but the boosting function unit experiences sudden load impedance increase causing excessive output voltage boosting
Solution Approach 1:
The patent applies preliminary anti-action by implementing a control strategy that prevents the harmful effect of excessive voltage boosting before it occurs. By coordinating the shutdown sequence to stop the boosting operation first while the inverter circuit continues running, the system counteracts the potential harm of sudden load impedance changes before they can cause element destruction.
3Loss of energy
If the boosting operation continues after inverter circuit stops, then voltage boosting is maintained for energy recovery, but the output voltage may excessively boost beyond rated breakdown strength of elements
Solution Approach 1:
The patent applies feedback by implementing voltage detection and control mechanisms that monitor the output voltage of the boosting function unit. When the inverter circuit stops, the system detects the voltage level and controls the boosting operation to prevent excessive voltage boosting that would exceed the rated breakdown strength of circuit elements, while still allowing energy recovery within safe 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 solution effectively prevents excessive voltage boosting, ensuring safe operation and prolonging the lifespan of components by managing load impedance fluctuations during the heating shutdown process.
Implementation Method 1
a boosting function unit that includes a choke coil and a switching element having a high potential side terminal connected to an output end of the choke coil, the switching element being used for a boosting operation in which the switching element is turned on to accumulate energy in the choke coil and is turned off to supply the energy to a capacitor of an output side via a diode
Implementation Method 2
an inverter circuit having a heating coil, which inputs the DC voltage outputted from the booster function unit to generate a high frequency current in the heating coil by the on/off operation of a different switching element
Implementation Method 3
an induction heating apparatus includes: a boosting function unit... an inverter circuit having a heating coil, which inputs the DC voltage outputted from the booster function unit to generate a high frequency current in the heating coil
Data Source
AI summary
An induction heating apparatus is capable of stop heating without excessively boosting output voltages of a booster circuit and a power factor correction circuit. The induction heating apparatus includes a boosting function unit, an inverter circuit, and a booster circuit controller. The boosting function unit includes a power factor correction circuit and a booster circuit, and boosts an input direct-current power to a direct-current voltage having a peak value larger than the peak value of the input direct-current power by turning on/off a switching element. The inverter circuit includes a heating coil, and inputs the direct-current voltage output by the boosting function unit to generate a high frequency current in the heating coil by turning on or off a different switching element. The booster circuit controller stops a boosting operation of the boosting function unit without a prescribed delay from the stop of an operation of the inverter circuit.