Adjustable Damping Capacitors for Induction Inverter Efficiency
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Solution Overview
Problem
Induction hobs with multiple inverters face inefficiencies due to undesired oscillations in resonant circuits, leading to power losses, particularly in matrix-type hobs where heating zones are dynamically formed based on cookware placement, requiring optimal damping to minimize scattering losses.
Innovation Solution
The induction hob incorporates a means to adjust the damping constant of damping arrangements connected to semiconductor switches, allowing for optimal damping by using a control unit to adjust the total capacity of the damping capacitor system, comprising adjustable capacitors and resistors, ensuring symmetrical damping and minimizing power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a damping capacitor is arranged in parallel to each semiconductor switch to prevent undesired oscillation, then oscillation is suppressed, but power losses increase due to incorrect sizing
Solution Approach 1:
The patent applies dynamics by making the damping capacitor system adjustable rather than fixed. The total capacitance can be dynamically changed based on operating conditions (power level, heating zone configuration), allowing optimal damping performance across different operating points while minimizing energy losses.
Solution Approach 2:
The patent changes the parameter of capacitance from a fixed value to an adjustable value. By varying the total capacitance of the damping capacitor system according to operating conditions, the system achieves optimal damping at different power levels and configurations, resolving the contradiction between reliable oscillation suppression and energy efficiency.
2Loss of energy
If the damping capacitor is correctly sized to minimize power losses, then efficiency improves, but the system cannot adapt to varying power requirements in matrix-type hobs
Solution Approach 1:
The damping capacitor system is designed to be dynamically adjustable, enabling it to adapt to varying power requirements in matrix-type hobs. Multiple capacitors can be switched in or out based on the operating point, allowing the system to maintain optimal damping performance across different heating zones and power levels.
Solution Approach 2:
The adjustable damping capacitor system serves multiple functions: it provides optimal damping for different power levels, adapts to various heating zone configurations in matrix-type hobs, and maintains efficiency across different operating conditions. This multi-functionality resolves the contradiction between minimizing losses and adapting to varying requirements.
3Adaptability or versatility
If multiple inverters are used in matrix-type hobs to enable flexible heating zone formation, then versatility improves, but scattering losses increase due to varying loads
Solution Approach 1:
Each inverter in the matrix-type hob is equipped with its own adjustable damping capacitor system, allowing local optimization of damping for each inverter's specific operating conditions. This local quality approach ensures that each inverter operates efficiently regardless of the overall heating zone configuration, minimizing scattering losses while maintaining versatility.
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 enhances the overall efficiency of the induction hob by reducing power losses and adapting to varying loads, particularly in matrix-type hobs, by dynamically adjusting the damping constant based on target power and other parameters, thereby preventing wastage and maintaining efficient heating performance.
Implementation Method 1
The damping arrangement can in particular comprise one or more capacitors and/or one or more resistors
Implementation Method 2
a damping arrangement which is arranged parallel to one of the semiconductor switches... This leads to a reduction in scattering losses
Implementation Method 3
The DC voltage source can in particular comprise a rectifier for rectifying a mains voltage of a household power network
Implementation Method 4
An inverter can then supply one or more inductors with a suitable heating current... generate a high-frequency alternating current... which flows through the inductors 30 and generates a magnetic field
Implementation Method 5
The magnetic field in turn generates alternating currents in the ferromagnetic base of the cookware element 34, thereby heating this base
Implementation Method 6
generates alternating currents in the ferromagnetic base... thereby heating this base
Data Source
Figure 1~2
Figure 3~5
AI summary
The invention relates to a household device having at least one power inverter (10) that comprises at least two semiconductor switches (14, 16) connected to a direct current voltage source (12) by different poles and at least two attenuation assemblies (18, 20) that are each arranged parallel to one of the semiconductor switches (14, 16). In order to reduce divergence loss due to the switching processes of the power inverter (10), according to the invention, the household device is equipped with at least one means (22) for adjusting an attenuation constant of at least one of the attenuation assemblies (18, 20).