Specifications-driven design space boundaries for Point-of-Load converters

Bjeletic, Aleksandar; Corradini, Luca; Maksimović, Dragan; Zane, Regan

doi:10.1109/apec.2011.5744741

Cited by 9 publications

(9 citation statements)

References 19 publications

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“…This integral gain K i must be limited in order for a single unit impulse of the error signal to produce a step change in the controlled quantity (e.g., output voltage). This condition is expressed in Equation (23). Theoretically, the parameter a is equal to 1, but in practice a, safety factor is considered, which can typically be a = 0.5.…”

Section: Limit Cycling Conditionsmentioning

confidence: 99%

Computer-Aided Design of Digital Compensators for DC/DC Power Converters

et al. 2018

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Digital control of high-frequency power converters has been used extensively in recent years, providing flexibility, enhancing integration, and allowing for smart control strategies. The core of standard digital control is the discrete linear compensator, which can be calculated in the frequency domain using well-known methods based on the frequency response requirements (crossover frequency, f c , and phase margin, PM). However, for a given compensator topology, it is not possible to fulfill all combinations of crossover frequency and phase margin, due to the frequency response of the controlled plant and the limitations of the compensator. This paper studies the performance space (f c , PM) that includes the set of achievable crossover frequencies and phase margin requirements for a combination of converter topology, compensator topology, and sensors, taking into account the effects of digital implementation, such as delays and limit cycling. Regarding limit cycling, two different conditions have been considered, which are related to the design of the digital compensator: a limited compensator integral gain, and a minimum gain margin. This approach can be easily implemented by a computer to speed up the calculations. The performance space provides significant insight into the control design, and can be used to compare compensator designs, select the simplest compensator topology to achieve a given requirement, determine the dynamic limitations of a given configuration, and analyze the effects of delays in the performance of the control loop. Moreover, a figure of merit is proposed to compare the dynamic performance of the different designs. The main goal is to provide a tool that identifies the most suitable compensator design in terms of the dynamic performance, the complexity of the implementation, and the computational resources. The proposed procedure to design the compensator has been validated in the laboratory using an actual DC/DC converter and a digital hardware controller. The tests also validate the theoretical performance space and the most suitable compensator design for a given dynamic specification.Energies 2018, 11, 3251 2 of 21 power factor corrector. In [13,14], state feedback is applied to multiphase power converters to ensure current-sharing. These techniques are suitable for keeping different quantities in control, typically current and voltage. Therefore, they can be considered as an alternative in multiple loop control structures.Reference [15] proposes a time-domain design method. The digital compensator is derived from specified rise time and overshoot. In [16], the compensator is designed based on the Internal Model Control design method used in motor control. In [17], complex zero compensation is used to improve transient response. In [18], the root locus method is applied to the calculation of a digital controller for a multiphase buck converter.Frequency domain techniques are very popular when designing analog linear compensators for DC/DC converters [19]. The compensator is calcula...

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Section: Limit Cycling Conditionsmentioning

confidence: 99%

Computer-Aided Design of Digital Compensators for DC/DC Power Converters

et al. 2018

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“…This converter could be used as the niBP of the DC-PDS. The limits Δv op and Δv ot imposed on the output voltage by the power quality requirements set a lower bound for the buck output capacitor C. These minimum values C(Δv op ), that guarantees a maximum steady state Δv op , and C(Δv ot ), which ensures a maximum Δv ot during a load step of magnitude ΔI o , can be calculated as in [14], [15].…”

Section: Converter Design Requirements In a Dc-pdsmentioning

confidence: 99%

“…In a synchronous buck converter, power losses are mainly due to the pair of MOSFETs and the inductor. The current ripple through the capacitors is commonly small enough to consider their losses negligible [15], although it is also relatively easy to model if the capacitor series resistance and the current flowing through them is known.…”

Section: Converter Design Requirements In a Dc-pdsmentioning

confidence: 99%

“…Previous works have defined design maps in order to ensure correct steady-state and transient operation for specific topologies [14], [15]. Based on a relatively large amount of design inputs, some of them being topology dependent, they provide an infinite amount of valid solutions for a single switching frequency.…”

Section: Converter Design Requirements In a Dc-pdsmentioning

confidence: 99%

“…They are determined by the maximum allowable inductor current ripple (Δi L ) and the minimum acceptable control loop crossover frequency (f c ) [14], [15].…”

Section: Converter Design Requirements In a Dc-pdsmentioning

confidence: 99%

See 2 more Smart Citations

Optimization procedure of source/sink converters for DC power distribution nano-grids

Martin

Vázquez

Arias

et al. 2018

2018 IEEE 19th Workshop on Control and Modeling for Power Electronics (COMPEL)

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Abstract-DC-Power Distribution Systems require DC-DC converters to interface all their elements. These converters should provide a high power quality and be efficient, compact and inexpensive. Furthermore, the characteristics of the loads and sources connected to these converters are not known beforehand and may change widely (there is no regulation about the DC loads, such as IEC61000-3-2 in AC grids). As a consequence, the design procedure is neither standard nor obvious. This work proposes an optimized design procedure for any Bus Provider in a DC-Power Distribution System. It is based on models, hence extensible to different Bus-Provider topologies, and takes into account the main issues in DC-Power Distribution Systems, especially the design conditions imposed by the wide variety of loads, or even sources, which may be connected to the output bus. Experimental results obtained from three designs show a close match with the analytical models and verify that the proposed procedure minimizes converter losses and complies with the requirements.

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Systematic approach to construct and assess power electronic conversion architectures using graph theory and its application in a fuel cell system

Zhang

2019

IET Power Electronics

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With the proliferation of renewable energy generations, power conversion systems (PCSs) are becoming much more complex; it is becoming challenging to search all possible power conversion architectures (PCAs) and find the best optimisation in terms of different objectives. Therefore, this study investigates a systematic approach to construct and evaluate PCAs using graph theory. First, the components in PCSs are graphically modelled as either nodes or edges. Then, a generalised PCA deduction methodology is proposed, and all possible PCAs can be mathematically deduced by modifying elements in adjacency matrices. For a fuel cell (FC) generation system, 45 possible PCAs are found with the proposed method. Furthermore, an evaluation methodology based on graph theory is proposed. The performance indices of the deduced PCAs, including costs, efficiency, and reliability, are calculated. Then, an optimisation approach is applied to finding the best architecture compromise, where the one with the shortest distance to the ideal architecture is considered the best architecture compromise. For the FC demo system, with the proposed assessment methodology, the best architecture compromise (dc-bus structure) is found among 45 possible architectures. Finally, the experimental platform, which adopts the dc-bus optimised architecture, is built and experimental results validate the architecture selection.

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Specifications-driven design space boundaries for Point-of-Load converters

Cited by 9 publications

References 19 publications

Computer-Aided Design of Digital Compensators for DC/DC Power Converters

Computer-Aided Design of Digital Compensators for DC/DC Power Converters

Optimization procedure of source/sink converters for DC power distribution nano-grids

Systematic approach to construct and assess power electronic conversion architectures using graph theory and its application in a fuel cell system

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