Interleaved Converter Switching Timing for Surge Voltage Suppression
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Solution Overview
Problem
Existing power conversion apparatuses, particularly those using interleaved converters, face challenges in preventing the generation of surge voltage without increasing the size and manufacturing cost of the apparatus.
Innovation Solution
A power conversion apparatus is designed with a converter circuit that includes multiple phases with reactors and switching elements, and a control unit that adjusts the timing of switching elements to prevent surge voltage generation by advancing or delaying the turn-off timing of one switching element relative to another.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple switching elements are turned on and off at close timings in an interleaved converter, then the input current magnitude is maintained, but surge voltages are superimposed and become higher
Solution Approach 1:
The control unit calculates a predetermined time difference based on circuit parameters (inductance and resistance) before switching operations occur. This preliminary calculation allows the system to proactively set appropriate time differences between switching elements, preventing surge voltage superposition before it happens while maintaining the required input current magnitude.
Solution Approach 2:
The invention dynamically adjusts the time difference parameter between switching element operations based on calculated circuit conditions. By changing this temporal parameter, the system optimizes the balance between maintaining input current magnitude and preventing harmful surge voltage superposition.
2Object-affected harmful factors
If the voltage resistance of switching elements is increased to handle surge voltage, then surge voltage is managed, but the switching elements become expensive and the apparatus size increases
Solution Approach 1:
The control unit proactively calculates and sets optimal time differences between switching operations before surge voltage problems occur. This preventive approach allows the use of switching elements with standard voltage resistance ratings, avoiding the need for expensive high-voltage-rated components and reducing overall apparatus cost and size.
Solution Approach 2:
The invention converts the potentially harmful effect of simultaneous switching into a beneficial control mechanism by deliberately introducing calculated time differences. This transforms what would be a problem (surge voltage) into a design parameter that optimizes both performance and cost-effectiveness.
3Object-affected harmful factors
If the capacity of the snubber circuit is increased to reduce surge voltage, then surge voltage is reduced, but the snubber circuit increases in size and manufacturing cost
Solution Approach 1:
The control unit preemptively calculates and implements optimal switching time differences based on circuit parameters, preventing surge voltage generation at its source. This eliminates the need for large-capacity snubber circuits, allowing the use of smaller, more cost-effective snubber components while still achieving surge voltage reduction.
Solution Approach 2:
The invention extracts the surge voltage suppression function from the snubber circuit and relocates it to the control unit's timing calculation and switching control. This separation allows the snubber circuit to be minimized in size while the control system handles the primary surge prevention function.
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 prevents surge voltage generation while maintaining the apparatus's size and manufacturing cost, thereby improving the reliability and efficiency of the power conversion process.
Implementation Method 1
A first example of the PFC circuit is a booster circuit using a plurality of switching elements and reactors
Implementation Method 2
When a switching element is turned on or off, surge voltage is generated at a terminal of the switching element due to an inductance component of a wire of a circuit
Data Source
AI summary
A power conversion apparatus includes a converter circuit and a control unit. The converter circuit includes circuits for the number of phases being more than one, the circuits each including a reactor and a corresponding first or second switching element connected to the reactor. The converter circuit converts an AC voltage output from a commercial power supply into a DC voltage. In a case where a time difference between a timing of turning off the first switching element and a timing of turning on the second switching element is within a threshold, the control unit performs control for advancing or delaying the timing of turning off the first switching element.