Interleaved Switchmode Power Stages for Fast Setpoint Tracking
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Solution Overview
Problem
Switchmode power converters face challenges in rapidly tracking setpoints due to inherent delays caused by large LC filters and limited switching frequencies, especially in high power applications, leading to increased ripple and reduced response times.
Innovation Solution
The implementation of a power supply system with interleaved switchmode power stages, where multiple buck converters are magnetically coupled and controlled to generate a target output waveform, allowing for instantaneous tracking of dynamic setpoints through interleaved pulse sequences and transformer configurations, reducing the need for large filters and increasing switching frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If larger LC filter components are used to reduce ripple, then ripple is reduced, but response time increases and delay between setpoint and output tracking increases
Solution Approach 1:
The power converter is divided into multiple parallel switchmode stages (e.g., two or more buck converters) that operate simultaneously. Each stage processes a portion of the input power and contributes to the total output, allowing the system to achieve both low ripple and fast response without requiring oversized filter components in a single stage.
Solution Approach 2:
Multiple switchmode power stages are combined in parallel with their outputs summed together. The magnetic coupling between stages through transformers enables the outputs to be added constructively, producing a combined output that has reduced ripple content while maintaining fast dynamic response characteristics.
2Object-generated harmful factors
If switching frequency is increased to reduce ripple and filter size, then ripple is reduced and filter size decreases, but switching losses increase and maximum practical frequency is limited
Solution Approach 1:
The overall power conversion task is segmented into multiple parallel stages, each operating at a moderate switching frequency. This allows the system to achieve an effective high-frequency response (N times the individual stage frequency) without requiring each individual stage to switch at excessively high frequencies, thereby limiting switching losses.
Solution Approach 2:
The interleaved stages switch in alternating periodic sequences, with each stage operating at a fundamental frequency but contributing to an output that effectively operates at N times that frequency. This periodic interleaving allows the system to benefit from high-frequency performance without the penalties of continuous high-frequency switching in a single stage.
3Power
If larger switches and LC components are used for high power applications, then power handling capability increases, but response time further increases and maximum switching frequency is limited
Solution Approach 1:
High power applications are divided into multiple parallel switchmode stages, each handling a portion of the total power. This segmentation allows each individual stage to use smaller, faster-switching components while the combined output achieves the required high power level, thereby maintaining fast response time despite high total power handling capability.
Solution Approach 2:
The system transitions from a single-dimensional approach (one large converter) to a multi-dimensional parallel architecture where multiple converters operate simultaneously. This dimensional change allows the system to achieve high power capability through parallel summation rather than through a single large component, bypassing the response time limitations inherent in large individual components.
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
This approach significantly reduces delays and ripple, enabling near-instantaneous response to setpoint changes and allowing for higher switching frequencies, thus improving the power converter's ability to handle high voltages and currents without the need for large capacitors or filters.
Implementation Method 1
a first output current magnetically coupled with a second output current of the second buck converter
Data Source
AI summary
An apparatus utilizing additive interleaved switchmode (PWM) power conversion stages, having minimal or no output filter, to achieve high bandwidth or even ideally instantaneous power conversion. The additive process may involve voltage stacking of isolated PWM converters, which are interleaved in time, or may involve a single input power supply and inductively combining output currents of PWM power converters interleaved in time, with either additive circuit having minimal or no output filtering. This circuit may overcome limitations for the frequency of feedback control loops once thought to be physical limitations, such as, fundamental switching frequency, output filter delay and the Nyquist criteria.