Non-Linear Digital Control Breaks Bandwidth Limitations

2009 Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exposition

et al. 2009

Self Cite

Abstract- Figure 1 shows the non linear and linear control scheme proposed in [1], it is based on a hysteretic control of the C out current. When a load step occurs: the non linear control leads the converter close to the new steady state and the linear control provides the accurate regulation. In the literature many current sensors design can be found, most of them measure the current in the inductor or in the power MOSFET. (In [25], an overview of current sensing techniques is presented). The dynamic performance of this control technique is very good although to measure the output capacitor current is very complex. The use of a series resistance is not viable since the output impedance is deteriorated, worsening the dynamic response of the converter. The use of a current transformer is less invasive although output impedance is still affected. The main disadvantages are the size, cost and integrating capability. Therefore, non-invasive technique must be used to avoid the increment of the C out impedance, reduce size and keep integrating capability. The design of the non-invasive current sensor is difficult since it is very sensitive to parasitic effects. This paper is organized as follows, section II explains the operating principle and design considerations, section III describes the proposed design methodology and design example. Section IV shows the experimental validation.

Section: Introduccionmentioning

confidence: 99%

Section: Introduccionmentioning

confidence: 99%

Design methodology of a non-invasive sensor to measure the current of the output capacitor for a very fast non-linear control

Huerta

2009 Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exposition

et al. 2009

Self Cite

“…The combination of non-linear and linear control proposed in [4] is based on a hysteretic control of the output capacitor current of a Buck converter. It achieves a faster control action under load steps since the output capacitor current reacts instantaneously.…”

Section: Introductionmentioning

confidence: 99%

V<sup>2</sup>I<inf>C</inf> control: A novel control technique with very fast response under load and voltage steps

Viejo

2011 Twenty-Sixth Annual IEEE Applied Power Electronics Conference and Exposition (APEC)

et al. 2011

Self Cite

Abstract-High switching frequencies (several MHz) allow the integration of low power DC/DC converters. Although, in theory, a high switching frequency would make possible to implement a conventional voltage mode control with very high bandwidth, in practice, parasitic effects and robustness make very complex to achieve bandwidths higher than 1MHz. This paper proposes a fast control technique to optimize the dynamic response of high switching frequency DC/DC converters. The proposed control is based on two loops. The fast internal loop has information of the output capacitor current and the error voltage, providing fast dynamic response under load and output voltage reference steps, while the slow external voltage loop provides accurate steady state regulation. Experimental results validate the fast dynamic response of the proposed control under load and output voltage reference steps and its suitability for high switching frequencies.

“…The non-linear and linear control scheme proposed in [1] is based on a hysteretic control of the output capacitor (C out ) current of a Buck converter. It achieves a faster control action under load steps since the output capacitor current reacts instantaneously (Fig.…”

Section: Introductionmentioning

confidence: 99%

“…However, the high bandwidth needed, if a linear control is used, is difficult to obtain because of parasitic effects, component variation and non-idealities of the error amplifier. One technique to face up to these limitations is the combination of non-linear and linear control [1], P].…”

Section: Introductionmentioning

confidence: 99%

Fast control technique based on peak current mode control of the output capacitor current

Viejo

2010 IEEE Energy Conversion Congress and Exposition

et al. 2010

Self Cite

-The control proposed and analyzed in this paper is based on the peak current mode control of the output capacitor current of a Buck converter. The output capacitor current loop provides fast dynamic response to the control since it behaves as a feed-forward of the load current while the voltage loop provides accurate steady state regulation. A simulation oriented averaged model of the proposed control has been developed to design the external voltage loop. As shown in simulations, with the converter switching at 5 MHz, the proposed control with a voltage loop of 50 kHz bandwidth has the same voltage drop and a similar dynamic response as a 1 MHz bandwidth voltage mode control. The reduction of the bandwidth makes easier the control implementation and integration. Finally, experimental results have been achieved verifying the fast dynamic response of the proposed control under load steps.Index Terms-DC/DC converters, high switching frequency, fast dynamic response, output capacitor current and integration.