Power Frequency Current Converter Variable Switching Control
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Solution Overview
Problem
Conventional power electronic converters using semiconductor switching devices face significant losses and thermal challenges, particularly due to high switching frequencies, which lead to increased junction temperatures and potential device damage during short-period overloads, necessitating costly and voluminous solutions for heat dissipation.
Innovation Solution
A power frequency current converter with a controller that generates at least two fixed-frequency control signals, allowing the switching device to operate at different frequencies within a half power frequency cycle, thereby distributing switching losses more evenly and reducing maximum junction temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the switching frequency of the semiconductor switching device is increased, then the power conversion efficiency is improved, but the switching losses increase and the junction temperature rises
Solution Approach 1:
The patent applies dynamics by making the switching frequency variable rather than fixed. The controller dynamically adjusts the switching frequency of the semiconductor switching device based on real-time operating conditions, allowing the system to optimize between conversion efficiency and switching losses adaptively throughout different operational states.
Solution Approach 2:
The patent changes the parameter of switching frequency from a constant value to a variable parameter that can be adjusted according to operating conditions. By modifying the switching frequency parameter dynamically, the system resolves the contradiction between maintaining high conversion efficiency and reducing switching losses.
2Loss of energy
If the switching frequency is reduced to decrease switching losses, then the switching losses decline, but the power conversion efficiency deteriorates
Solution Approach 1:
The system uses dynamic frequency adjustment to resolve this contradiction. Rather than operating at a fixed low frequency that would reduce switching losses but harm efficiency, the controller dynamically varies the frequency to maintain optimal efficiency while keeping switching losses low through adaptive timing.
Solution Approach 2:
The switching frequency parameter is changed from a static low value to a dynamically adjustable parameter. This allows the system to achieve low switching losses while maintaining high conversion efficiency by optimizing the frequency parameter according to actual operating conditions.
3Temperature
If conventional heat dissipation designs or higher rated current switches are used to manage junction temperature, then the maximum operating junction temperature is controlled under 150°C, but the cost and volume of the system increase
Solution Approach 1:
The patent applies preliminary action by proactively controlling the switching frequency to prevent excessive junction temperature rise before it occurs. The controller adjusts the frequency in advance based on predicted thermal conditions, avoiding the need for complex reactive heat dissipation systems or oversized semiconductor devices.
Solution Approach 2:
The system changes the operating parameters (switching frequency) to manage junction temperature instead of relying on physical heat dissipation structures. By adjusting the frequency parameter, the thermal load is controlled, eliminating the need for complex heat sinks or higher-rated switches.
4Power
If the junction temperature variation amount is increased during overload, then the short-period overload capability is improved, but the bonding wires may break due to heat stress
Solution Approach 1:
The patent uses dynamic frequency adjustment to manage thermal stress during overload conditions. By rapidly varying the switching frequency, the system distributes thermal load more evenly over time, preventing the cumulative heat stress that would cause bonding wire failure while still maintaining overload capability.
Solution Approach 2:
The patent applies periodic action through pulse-width modulation (PWM) control, where the switching device operates in periodic on-off cycles. This periodic operation distributes the thermal load across multiple cycles rather than concentrating it continuously, reducing peak thermal stress on bonding wires while maintaining power delivery capability during overload.
Data Source
AI summary
The present disclosure provides a power frequency current converter, including: an input side and an output side, wherein a current of the input side or the output side is a power frequency current; a switching device; and a controller, configured to control the switching device to be turned on and turned off at an operating frequency, wherein within a half of a power frequency cycle, the controller generates at least two fixed-frequency control signals and the operating frequency of the switching device alters at least twice according to the at least two fixed-frequency control signals, so as to reduce junction temperature of the switching device.