Electric grill with current protection circuitry
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Solution Overview
Problem
Existing electric grills lack advanced protection circuitry to detect and prevent dangerous current conditions such as short circuits, overcurrent, driver failure, and microcontroller failure, especially in harsh outdoor environments.
Innovation Solution
The electric grill incorporates a protection circuit with a microprocessor, triacs, latch relays, a Hall Effect sensor, and a watchdog monitor to detect unsafe current conditions and disable the flow of electricity, thereby preventing damage and ensuring user safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior art electric cooking devices use simple current protection schemes relying on wall outlet protection and ground lines, then device complexity is reduced, but reliability is insufficient for harsh outdoor environments where component degradation occurs
Solution Approach 1:
The protection system is divided into multiple independent monitoring functions: overcurrent detection, ground fault detection, driver failure detection, and microcontroller failure detection. Each function operates independently through dedicated circuitry (current transformer, Hall Effect sensor, watchdog monitor) to provide comprehensive protection without requiring a single complex protection mechanism.
Solution Approach 2:
The protection circuitry continuously monitors current conditions and component status before dangerous failures occur. The system detects abnormal conditions (overcurrent, ground faults, driver failures) and shuts down heating elements proactively, preventing catastrophic failures and safety hazards before they can develop.
2Reliability
If thermally-responsive circuits are used to shut down heating elements at threshold temperatures, then overheating protection is provided, but current leakage and dangerous current conditions cannot be detected
Solution Approach 1:
A current transformer is introduced as an intermediary device to monitor current flow through the heating elements. This non-intrusive sensor detects current imbalances, ground faults, and overcurrent conditions without requiring direct electrical contact with high-voltage circuits, enabling comprehensive current monitoring while maintaining electrical isolation.
Solution Approach 2:
The patent replaces purely thermal protection mechanisms with electrical field-based detection using Hall Effect sensors and current transformers. These electromagnetic sensing methods can detect current anomalies independent of temperature, allowing the system to identify dangerous current conditions (ground faults, overcurrent) that would not necessarily cause overheating.
3Reliability
If MOSFETs are used to regulate current in prior art circuits, then current control is achieved, but multiple types of failure conditions including ground faults and driver failures cannot be detected
Solution Approach 1:
The protection circuitry is designed with multi-functionality to detect various failure modes through unified monitoring principles. The current transformer and Hall Effect sensor serve multiple detection purposes (overcurrent, ground faults, driver failures), while the watchdog monitor provides independent verification of microcontroller operation, creating a universal protection architecture that handles diverse failure conditions.
Solution Approach 2:
The system implements continuous feedback monitoring where current sensors feed real-time current data to the microcontroller, which compares actual current draw against expected values. This feedback mechanism enables detection of driver failures and abnormal operating conditions, allowing the system to respond by shutting down heating elements when anomalies are detected.
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
The solution effectively protects the electric grill and its users from unsafe current conditions by detecting and responding to failures and anomalies, ensuring safe operation in harsh outdoor environments.
Implementation Method 1
A Hall Effect sensor measures a current passing through the triac
Data Source
AI summary
Provided is an apparatus and method for protecting against unsafe electric current conditions. A protections circuit may be used in a device, such as an electric grill, that has one or more electric loads, such as heating elements. The protection circuit may protect against various failure scenarios, including, without limitation, instances of ground fault, over current, driver failure, and failure of a microprocessor. In response to a failure, the protection circuit may trip a latch relay or disable a triac driver to stop current from flowing.