Discrete Switching Speed Allocation for Power Conversion Loss Reduction
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Solution Overview
Problem
Existing power conversion circuits for vehicles face challenges in reducing losses when switching speeds are continuously changed, leading to increased complexity and cost, while discrete changes in switching speed result in decreased loss reduction effects.
Innovation Solution
A driving apparatus for switching elements in a power conversion circuit that sets discrete turn-on and turn-off speeds based on parameters correlated with output torque, with more speeds allocated in ranges with higher occurrence frequencies, minimizing overall complexity and enhancing loss reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If switching speed is continuously changed, then loss reduction effect is improved, but device complexity and cost increase
Solution Approach 1:
The patent segments the continuous switching speed control into multiple discrete switching speed levels. The switching element operates at different discrete switching speeds selected from a predetermined set, rather than continuously variable speeds. This segmentation reduces the complexity of the control system while still achieving effective loss reduction across different operating conditions.
Solution Approach 2:
The patent implements dynamic switching speed selection by automatically adjusting the discrete switching speed level based on real-time operating conditions such as switching frequency and load characteristics. The control unit dynamically selects appropriate switching speeds from the predetermined discrete levels, enabling adaptive loss reduction without requiring continuous variable control mechanisms.
2Device complexity
If switching speed is discretely changed, then device complexity is reduced, but loss reduction effect decreases
Solution Approach 1:
The patent changes the parameter of switching speed across multiple discrete levels rather than maintaining a single fixed value. By providing a predetermined plurality of discrete switching speeds and selecting appropriate levels based on operating conditions, the system achieves effective loss reduction while keeping the control mechanism relatively simple. The parameter change approach allows optimization of switching losses without requiring continuous variable control.
Solution Approach 2:
The patent applies different discrete switching speed levels to different operating conditions locally. Rather than using a uniform switching speed strategy, the system selects specific discrete switching speeds tailored to particular operating ranges and load conditions. This local optimization approach ensures effective loss reduction in each specific operating scenario while maintaining overall system simplicity.
3Loss of energy
If multiple discrete switching speeds are provided, then loss reduction effect is improved in localized ranges, but total number of switching speeds increases complexity
Solution Approach 1:
The patent provides a predetermined plurality of discrete switching speeds that covers the necessary operating ranges without requiring an excessively large number of levels. By selecting an appropriate number of discrete switching speed levels that suffices for most operating conditions, the system achieves effective loss reduction in localized ranges while avoiding unnecessary complexity from having too many switching speed options.
Data Source
AI summary
A power conversion circuit is mounted in a vehicle and controls an output torque of the rotating machine based on a requested command torque. A driving apparatus of a switching element controls a current flowing to the rotating machine. The driving apparatus sets at least one of a turn-on speed and a turn-off speed for the switching element to a plurality of switching speeds that are discretely determined, based on a parameter that is correlated with the output torque and has a controllable value. The driving apparatus turns on or off the switching element at the switching speeds. The switching speeds are allocated to the respective magnitudes of the parameter at uneven intervals, and determined such that the number of allocated switching speeds is greater in a range in which an occurrence frequency of the parameter is high, compared to a range in which the occurrence frequency is low.