An enhanced adaptive frequency locked loop for variable frequency controls

Bari, Syed Mustafa Khelat; Li, Qiang; Lee, Fred C.

doi:10.1109/apec.2017.7931184

Cited by 3 publications

(4 citation statements)

References 12 publications

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“…In particular, this relation is specific to solving reach-avoid-stay game with specification Φ defined in Eq. (4). In what follows, we formally state this relation.…”

Section: A Raw Abstractionmentioning

confidence: 99%

“…Given the hybrid automaton H, the LTL specification Φ defined in Eq. ( 4), and an initial state x init (or a set of initial states X init ) 4 , the goal is to find a switching controller under which all the executions of H starting from X init and t d = N dwell + N grace (i.e., starting from mode 2) satisfy LTL formula Φ. In particular, the control action needs to be determined based on the history of x, but not x.…”

Section: Problem Statementmentioning

confidence: 99%

“…In this work, we consider controller design for a specific power converter called constant on-time buck converter. Such converters are widely used in voltage regulator modules and point-of-load converter applications [4]. The converter usually has two switches as actuators, denoted as S 1 and S 2 respectively, and the term "constant on-time" indicates that the turn-on time of the switch S 1 is kept constant.…”

Section: Introductionmentioning

confidence: 99%

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Correct-by-construction control synthesis for buck converters with event-triggered state measurement

Yang

Cui

Avestruz

et al. 2019

2019 American Control Conference (ACC)

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In this paper, we illustrate a new correct-byconstruction switching controller for a power converter with event-triggered measurements. The event-triggered measurement scheme is beneficial for high frequency power converters because it requires relatively low-speed sampling hardware and is immune to unmodeled switching transients. While providing guarantees on the closed-loop system behavior is crucial in this application, off-the-shelf abstraction-based techniques cannot be directly employed to synthesize a controller in this setting because controller cannot always get instantaneous access to the current state. As a result, the switching action has to be based on slightly out-of-date measurements. To tackle this challenge, we introduce the out-of-date measurement as an extra state variable and project out the inaccessible real state to construct a belief space abstraction. The properties preserved by this belief space abstraction are analyzed. Finally, an abstraction-based synthesis method is applied to this abstraction. We demonstrate the controller on a constant on-time buck voltage regulator plant with an event-triggered sampler. The simulation verifies the effectiveness of our controller.

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“…In particular, this relation is specific to solving reach-avoid-stay game with specification Φ defined in Eq. (4). In what follows, we formally state this relation.…”

Section: A Raw Abstractionmentioning

confidence: 99%

Section: Problem Statementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Correct-by-construction control synthesis for buck converters with event-triggered state measurement

Yang

Cui

Avestruz

et al. 2019

2019 American Control Conference (ACC)

View full text Add to dashboard Cite

show abstract

“…In addition, the frequency stability of constant on-time buck converter is generally affected by on-time variation under different operating conditions [22]. To improve the frequency stability, the converter in [23] adopts a frequency locked loop to generate a constant frequency, and the circuits in [24] utilize predicting correction technique (PCT) to suppress the switching frequency variation. However, the PCT technique requires the accurate value of device parasitic resistances, and large-ESR output capacitor is required to ensure the system stability.…”

Section: Introductionmentioning

confidence: 99%

A Pseudo-Constant Frequency Constant On-Time Buck Converter With Internal Current Ripple Injection and Output DC Offset Cancellation

Sun

et al. 2019

IEEE Access

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A constant on-time buck converter with internal inductor current synthesizer and output DC offset cancellation technique is proposed. A fully integrated inductor current synthesizer based on valley voltage detector is employed to avoid system instability for constant on-time converters with low-ESR output capacitors. Moreover, the valley voltage detector could shift the emulated inductor current signal to zero valley level. In this way, the output DC offset due to ripple injection variation could be eliminated. An on-time circuit with comparator delay compensation is presented to alleviate the switching frequency variation. The small-signal model and design criteria are derived for system stability design. The circuit has been implemented with 0.18 µm BCD process. The measurement results show that the transient response is about 15.4 µs and the overshoot or undershoot voltage is less than 36 mV when the load transient between 1 A and 5 A for input voltage of 12 V and output voltage of 1.05 V. The switching frequency across load variation f SW / I LOAD is 4.6 kHz/A at the nominal frequency of 700 kHz. The output DC offset is less than 10 mV in case of 4 A load current change. INDEX TERMSConstant on-time control, emulated inductor current synthesizer, ripple-based converter, switching frequency, valley voltage detector.

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Correct-by-construction control synthesis for buck converters with event-triggered state measurement

Yang

Cui

Avestruz

et al. 2019

Preprint

View full text Add to dashboard Cite

An enhanced adaptive frequency locked loop for variable frequency controls

Cited by 3 publications

References 12 publications

Correct-by-construction control synthesis for buck converters with event-triggered state measurement

Correct-by-construction control synthesis for buck converters with event-triggered state measurement

A Pseudo-Constant Frequency Constant On-Time Buck Converter With Internal Current Ripple Injection and Output DC Offset Cancellation

Correct-by-construction control synthesis for buck converters with event-triggered state measurement

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