Galvanic Isolation in Corona Ignition Supply Circuit
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Solution Overview
Problem
Existing corona ignition systems in vehicles face challenges in safely and reliably generating a high supply voltage from the on-board electrical system voltage, which is typically low, and lack effective galvanic separation to prevent damage from secondary side defects.
Innovation Solution
A supply circuit using two resonant converters with parallel primary sides and series secondary sides, connected in series with diodes, and a bridge circuit with transistor switches, along with a storage capacitor, to ensure reliable power delivery and emergency operation by isolating defects to the secondary side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If converters without galvanic separation (e.g., charge pumps or upwards converters) are used, then the device complexity is reduced, but defects on the secondary side can penetrate to the primary side and cause major damage
Solution Approach 1:
The patent divides the power conversion system into two separate converters (first converter and second converter) with galvanic isolation between primary and secondary sides. This segmentation prevents defect propagation from secondary to primary side, protecting the system while maintaining manageable complexity through modular architecture.
2Device complexity
If a single converter is used, then the device complexity is reduced, but the supply security and functionality are compromised when the converter fails
Solution Approach 1:
The patent implements a redundant converter configuration where a second converter is prepared in advance to take over if the first converter fails. The switching mechanism is pre-configured to enable seamless transition, providing insurance against converter failure and maintaining supply security without requiring complex real-time diagnostics.
3Ease of operation
If the on-board electrical system voltage (12V or 24V) is used directly as input, then the ease of operation is improved, but the power level is insufficient for corona ignition requirements
Solution Approach 1:
The patent employs voltage conversion through resonant converters to transform the low-voltage on-board electrical system voltage (12V or 24V) into the high-voltage supply required for corona ignition. The resonant conversion process efficiently changes voltage parameters while maintaining power delivery capability, enabling operation from standard vehicle electrical systems.
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 configuration significantly reduces the risk of primary side damage, maintains system functionality, and allows for reduced engine speed operation in case of converter failure, enabling the vehicle to drive to a workshop independently.
Implementation Method 1
The use of converters with transformers that exhibit two magnetically coupled coils enables a galvanic separation of the primary side of the converter from the secondary side
Implementation Method 2
Another advantageous refinement of this disclosure provides that the converters be resonant converters
Implementation Method 3
The secondary side of each of the two converters is here connected in parallel with a diode; the secondary sides connected in series are thus each bridged by at least one diode
Implementation Method 4
a respective bridge circuit with at least four transistor switches be arranged between the input and primary side of the converters
Implementation Method 5
a storage capacitor be connected in parallel with the load connected to the output of the supply circuit
Data Source
AI summary
Described is a supply circuit for a corona ignition device, with an input for connection to a direct voltage source, a first converter, a second converter, and an output for connecting a load. The two converters each generate an output voltage, which is provided on its secondary side and exceeds the input voltage. The two converters each contain a transformer that galvanically separates the primary side of the converter from its secondary side. At least one transistor switch is arranged between the input and primary side of the two converters for pulse width-modulation of the input voltage. The primary side of the second converter is connected in parallel with the primary side of the first converter, the secondary side of the second converter is connected in series with the secondary side of the first converter, the secondary sides of the two converters are each bridged in this series connection by at least one diode, so that an output voltage can be provided at the output of the supply circuit even given a failure of one of the two converters.