Current estimation circuit for discontinuous conduction mode flyback pulse‐width modulation controller

Shi, Lei; Qi, Yihong

doi:10.1049/iet-pel.2014.0358

Cited by 22 publications

(5 citation statements)

References 19 publications

(25 reference statements)

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“…The equivalent primary current i m is used for analysis. i m can be expressed in (7). m 1 and m 2 are the increasing slope and decreasing slope of i m in t on and t r periods, separately.…”

Section: The Fixed Switch-off Time Control With Time-length Compensmentioning

confidence: 99%

“…[3][4][5][6][7][8][9][10][11][12] In PSR flyback converter, discontinuous conduction modulation (DCM) mode is mostly used for small power. [6][7][8][9][10][11] To improve the power density, continuous conduction modulation (CCM) mode will be introduced. [13][14][15][16] In digital control, the inductor average current is always required for the output current estimation.…”

Section: Introductionmentioning

confidence: 99%

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A simple average current control with time‐length equality for primary‐side regulation flyback converter with constant output current control

Wang

Kou

et al. 2018

Circuit Theory & Apps

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Primary-side regulation (PSR) flyback converter is widely used in small power applications. To increase the output power, continuous conduction modulation mode is always introduced. In this paper, a simple average current control method with very low cost is proposed for constant current controlled PSR flyback converter in both continuous conduction modulation mode and discontinuous conduction modulation mode. The average current control method is realized with time-length equality by simply comparing the average current with switch current, such that analog-to-digital converter for current sampling in traditional average current control method is removed. In addition, to eliminate the subharmonic oscillation and keep low cost, a fixed switch-off time control with time-length compensation algorithm is used. To improve the output current accuracy, a hysteretic multimode control method is applied. The total control requires very low implementation costs that only contain a lowspeed Digital to analog converter (DAC), three comparators, and a digital controller. The performance of the proposed control method is experimentally verified on an Field-progrannable gate array (FPGA) controlled 3.8 to 16 V/3.8 A PSR flyback converter. In experiments, stable control and high output current accuracy are obtained, and the output current accuracy is within ±1.8% under universe line voltage and output load.

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“…The equivalent primary current i m is used for analysis. i m can be expressed in (7). m 1 and m 2 are the increasing slope and decreasing slope of i m in t on and t r periods, separately.…”

Section: The Fixed Switch-off Time Control With Time-length Compensmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A simple average current control with time‐length equality for primary‐side regulation flyback converter with constant output current control

Wang

Kou

et al. 2018

Circuit Theory & Apps

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“…Frequency analysis proves that VCM can achieve similar steady-state and transient responses as its peak current mode (PCM) counterpart. Furthermore, current observation strategies are used in current mode control, which replaces conventional current sensors, and saves cost, power and size of the converter system [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Voltage‐extrapolative charge balance controller with charge compensation for flyback converter operating in DCM

Zhang

Min

Ji³

et al. 2019

IET Power Electronics

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This study presents a voltage-extrapolative charge balance (VECB) controller with charge compensation for flyback converter operating in discontinuous conduction mode (DCM). Compared with conventional charge balance controller, the VECB controller benefits from voltage extrapolation, which improves the transient response to load disturbance. Based on the output voltage differential value, a voltage extrapolator calculates the output voltage after two switching cycles under the influence of discharge. Furthermore, the extrapolated voltage is used to calculate the reference charge for the next switching cycle. The VECB controller eliminates the lag in calculating the reference charge, which improves the transient response to load disturbance. Closed-loop small signal models under VECB and conventional charge balance controls are derived and compared to prove the improvement. Furthermore, charge damping and its influence to the output voltage are intensely studied. To minimise the influence, a constant factor is adopted to carry out charge compensation, which is proved to be adequate. Finally, the effectiveness of VECB controller is verified on a flyback converter prototype.

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“…Frequency analysis proves that the VCM can achieve similar steady-state and transient response performance to its PCM counterpart. Furthermore, current observation (or estimation) strategies are used for current mode control, which replaces conventional current sensors, and saves cost and power, and reduces the size of the converter system [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

An Optimized Sensorless Charge Balance Controller Based on a Damped Current Model for Flyback Converter Operating in DCM

et al. 2018

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This paper presents an Optimized Sensorless Charge Balance (OSCB) controller based on a damped current model for flyback converter operating in Discontinuous Conduction Mode (DCM). By solving total differential equations of non-ideal transformer currents, the damped current model is derived with consideration of parasitics, leakage inductance of transformer, and the Resistor-Capacitor-Diode (RCD) snubber circuit. Based on the proposed model, current observation and control algorithms of the Sensorless Charge Balance (SCB) controller are optimized, which forms the OSCB control strategy. The average current damping is considered in the equivalent discrete-time small signal model. Furthermore, frequency analyses show that OSCB controller achieves higher closed-loop bandwidth and lower overshoot than a SCB controller, which indicates an improved transient performance. Finally, both OSCB and conventional SCB controllers are experimentally evaluated on a flyback converter prototype.

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Current estimation circuit for discontinuous conduction mode flyback pulse‐width modulation controller

Cited by 22 publications

References 19 publications

A simple average current control with time‐length equality for primary‐side regulation flyback converter with constant output current control

A simple average current control with time‐length equality for primary‐side regulation flyback converter with constant output current control

Voltage‐extrapolative charge balance controller with charge compensation for flyback converter operating in DCM

An Optimized Sensorless Charge Balance Controller Based on a Damped Current Model for Flyback Converter Operating in DCM

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