Interleaved Power Converter Current Balancing Controller
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Solution Overview
Problem
Interleaved power converters face current imbalances due to timing differences between phases, leading to increased RMS currents, transformer saturation, and reduced reliability, which existing solutions address by directly sensing currents in each switch, increasing complexity and cost.
Innovation Solution
A controller for interleaved power converters that senses input currents at specific sample points relative to switch-on and switch-off times to determine current imbalances and adjusts the on-time interval of switching devices to compensate, reducing the need for direct current sensing in each switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct current sensing is implemented in each switch to detect and adjust current imbalances, then current balance between phases is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the current sensing function from individual switch locations and relocates it to a single common point (the DC voltage source). By sensing the total input current and using timing information to attribute portions to each phase, the system achieves current balance without requiring separate current sensors in each switch, thereby reducing device complexity while maintaining reliability
Solution Approach 2:
The patent introduces timing information as an intermediary element that mediates between the single sensed input current and the multiple phase currents. By using the known switch-on and switch-off times to calculate what each phase current should be, the system indirectly determines phase currents without direct sensing, resolving the contradiction between accurate current measurement and simplified hardware
2Reliability
If direct current sensing is implemented in each switch to determine current imbalances, then current balance is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges multiple current sensing functions into a single sensing location at the DC voltage source. Instead of requiring separate current sensors for each phase (which would increase manufacturing cost), the system combines the sensing function into one shared resource and uses computational methods to derive individual phase currents, thereby reducing component count and manufacturing cost while maintaining current balance capability
Solution Approach 2:
The patent creates a virtual copy of the current sensing function through calculation rather than physical duplication of sensors. By using the timing information to calculate what each phase current should be based on the total sensed current, the system replicates the information-gathering capability without requiring physical sensor copies, reducing manufacturing cost
3Reliability
If processor power is increased to handle direct current sensing from multiple switches, then current balance control is improved, but loss of energy increases
Solution Approach 1:
The patent extracts the computationally intensive current measurement task from the processor and relocates it to simple timing measurements and basic calculations. By measuring switch-on and switch-off times rather than processing multiple analog current signals, the system significantly reduces processor workload and energy consumption while maintaining current balance control capability
Data Source
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Figure 3a~4
Figure 5a~5b
AI summary
An interleaved power converter for converting a DC voltage source into a DC voltage output, the converter comprising:- two or more sub-circuits connected in parallel, each sub-circuit comprising an inductive element (L1, T1), a rectifying element (D1, D2) and a controllable switching device (M1, M2) connected for converting a DC voltage source (25) into a DC voltage output (23,24); driving means (PWM1, PWM2) for driving the switching device of each sub-circuit to repeatedly switch on at a time t1 and off at a time t2, with a phase difference between the switch-on times t1 of each switching device; current sensing means for repeatedly determining an input current value associated with each sub-circuit, by sensing the input current of the converter at a sample point a pre-determined time relative to the switch-on time t1 or the switch-off time t2 of said switching device; and control means comprising:- comparator means for comparing the input current value determined at each sample point with the input current value determined at the preceding sample point, to obtain a measure of current imbalance attributable to one or both of the sub-circuits with which the compared input current values are associated; and current balancing means for adjusting the time interval Ton from t1 to t2, for one or both of the sub-circuits with which the compared input current values are associated, to compensate for said current imbalance.