Induction Hob Bus Capacitor Discharge for Low-Loss Vessel Detection
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Solution Overview
Problem
Existing induction hob apparatuses suffer from low efficiency in discharging bus capacitors due to high electrical losses in methods like using high-resistance resistors, which interfere with cookware detection at high sample rates.
Innovation Solution
The induction hob apparatus employs a discharging unit with high-side and low-side switch elements that periodically discharge the bus capacitor via the current supply network, minimizing losses and enabling efficient cookware detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high-resistance resistors are used to discharge the bus capacitor, then the capacitor can be discharged, but high electrical losses occur reducing efficiency
Solution Approach 1:
The patent replaces the passive resistive discharge mechanism with an active electronic switching mechanism using MOSFETs. The discharging unit uses controlled switching elements to create a low-impedance discharge path, substituting the high-loss mechanical/resistive system with an electronically controlled system that minimizes energy dissipation while achieving the same capacitor discharge function.
Solution Approach 2:
The patent changes the electrical parameters of the discharge path by using switch elements with very low on-resistance compared to high-resistance discharge resistors. By controlling the resistance parameter dynamically through switching, the system achieves efficient discharge with minimal energy loss, directly addressing the contradiction between discharge capability and energy efficiency.
2Measurement precision
If the bus capacitor is discharged frequently for high sample rate cookware detection, then detection accuracy improves, but energy efficiency deteriorates due to continuous discharge losses
Solution Approach 1:
The patent replaces the energy-wasteful resistive discharge system with an electronically controlled switching system that can perform discharges with minimal energy loss. This substitution enables frequent discharges for high sample rate detection without proportionally increasing energy consumption, thus resolving the contradiction between measurement precision and energy efficiency.
Solution Approach 2:
The patent implements periodic discharge control through the discharging unit, which can be activated at controlled intervals to maintain capacitor voltage within optimal ranges for high sample rate cookware detection. This periodic action with the new low-loss switching mechanism allows frequent measurements while minimizing total energy loss compared to continuous resistive discharge.
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 reduces energy waste by up to 10 W per phase and allows for efficient cookware vessel detection at high sampling rates, improving overall efficiency and reducing installation space and costs.
Implementation Method 1
at least one rectifier (14a, 14b, 14c, 14d, 14e) for current flow during a positive network voltage partial cycle via a first charging path (18a, 18b, 18c, 18d, 18e) and for current flow during a negative network voltage partial cycle via a second charging path (20a, 20b, 20c, 20d, 20e)
Implementation Method 2
a bus capacitor (12a, 12b, 12c, 12d, 12e), wherein the bus capacitor is connected via the rectifier to the network connection (16a, 16b, 16c, 16d, 16e)
Implementation Method 3
the switch elements are provided such that, in a closed state, they enable a discharging path from the bus capacitor back to the network connection (16a, 16b, 16c, 16d, 16e)
Data Source
AI summary
An induction hob apparatus includes a network connection connected to a current supply network, a rectifier, and a bus capacitor connected to the network connection via the rectifier via a first charging path for charging during a positive network voltage partial cycle and via a second charging path for charging during a negative network voltage partial cycle. A discharging unit includes at least two switch units, each including a switch element for periodic discharging of the bus capacitor via the current supply network. One switch unit is embodied as a high-side switch unit with a high-side switch element and another switch unit is embodied switch units as a low-side switch unit with a low-side switch element. The switch elements of the at least two switch units are provided to enable, in a closed state, a discharging path from the bus capacitor back to the network connection.