Power Converter Controller With DMA-Driven Variable-Frequency PWM
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Solution Overview
Problem
Conventional PWM signals have a fixed frequency, which limits the flexibility in controlling power converters to produce varying output waveforms, such as sinusoidal outputs required for applications like wireless power transfer.
Innovation Solution
A controller for power converters is designed to generate PWM signals with modulated repetition rates, using a generator module that stores rise moment, fall moment, and repetition period values. This allows for the generation of PWFM signals, providing flexible control over pulse width and frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional PWM signals with fixed frequency are used, then the control structure is simple, but the flexibility in controlling power converter outputs is limited
Solution Approach 1:
The patent implements dynamic control by allowing the repetition period RP to be modified during operation through DMA-triggered updates from lookup tables. This enables the PWM signal to transition from fixed frequency to variable frequency operation, providing adaptability for different power converter modes (PWM, PFM, or hybrid PWFM) without requiring a complete redesign of the controller architecture.
Solution Approach 2:
The patent pre-stores multiple repetition period RP values and pulse width parameters in lookup tables within the memory module before operation. When specific control modes are needed, the DMA controller simply triggers the retrieval of pre-calculated parameters from these tables, eliminating the need for complex real-time calculations and reducing the operational complexity of implementing flexible control.
2Adaptability or versatility
If the repetition period RP is modified dynamically to enable variable frequency operation, then the flexibility and adaptability of the controller is improved, but the complexity of the control system increases
Solution Approach 1:
The patent introduces a DMA controller as an intermediary component that bridges the memory module containing lookup tables and the pulse generator module. This intermediary automatically retrieves pre-stored RP values and transfers them to the generator module upon trigger signals, eliminating the need for complex software or hardware logic to dynamically modify the repetition period, thus maintaining system simplicity while enabling variable frequency operation.
Solution Approach 2:
The patent extracts the complex task of dynamic parameter calculation and management into a separate memory module containing pre-computed lookup tables. This separates the complex computational functions from the simple pulse generation function, allowing the generator module to remain relatively simple while still achieving variable frequency control through externally supplied parameters.
3Speed
If lookup tables with pre-stored R, F, and RP values are used, then the speed of parameter updates is improved, but the memory requirements increase
Solution Approach 1:
The patent implements partial action by storing only the essential critical parameters (repetition period RP, rise moment R, and fall moment F) in the lookup tables rather than storing complete PWM waveforms or all possible control parameters. This selective storage of only the most important parameters that directly control the pulse characteristics achieves fast update speeds while minimizing the memory table size to only what is strictly necessary.
Data Source
AI summary
A controller for a power converter includes a generator module which generates a sequence of pulses each having a width defined by a rise moment and fall moment stored in respective RM and FM registers. The sequence of pulses have a repetition rate that is modulated by a repetition period value stored in a RP register. A memory of the controller has tables of rise moment values, fall moment values and repetition period values configured to be written into the RM, FM and RP registers respectively. A direct memory access (DMA) module of the controller is configured to write rise moment, fall moment, and repetition period values from the respective memory table into the RM, FM, and RP registers respectively, in response to a DMA trigger. A core coupled to the DMA module is configured to write the rise moment, fall moment, and repetition period values into the memory tables.