Digital hybrid current mode control for DC–DC converters

Abstract

A digital hybrid current mode (HCM) control technique which combines peak current and average current mode (ACM) control methods is studied. The proposed controller consists of three control loops, an analogue fast current loop, a digital slow current loop and an outer voltage loop. For the control method, both continuous and discrete-time models are built. Similarly, a continuous-time model for ACM control is provided for comparison. For both control techniques, a compensator design method is proposed. The control methods are implemented on a 6 W synchronous buck converter with a mixed-signal ARM-based microcontroller. Controller models are verified with the frequency response measurements of the inner and outer loops. In digital HCM control, higher DC gain and phase margin is achieved with the same gain margin compared to digital ACM control. Furthermore, the transient responses of the systems are analysed. When the outer voltage loop is open, 30% faster dynamic response is measured by the digital HCM method. With voltage compensation, comparable dynamic response on the output voltage is achieved without inductor current overshooting by the digital HCM control.

Review on Performance Analysis of Three Control Techniques for Buck Converter feeding a Resistive Load

“…Several control techniques have been applied to control the output voltage, current, and switch duty cycle of a buck converter. Voltage mode control (VMC) [21], current-mode control (CMC) [22], state-space average model [23], proportional-integral (PI) [10] and proportional-integral-derivative (PID) [5]- [10] are well-known basic linear control methods. However, in the case of large input voltage and load fluctuations, conventional linear control techniques cannot perform efficiently.…”

“…A boost converter's voltage mode control (VMC) is designed and implemented in [21]. Digital hybrid current mode (HCM) control of a dc/dc converter is designed and implemented in [22]. In [23], two half-bridge dc/dc converters are designed using an average state-space method.…”

Design of Digitally Controlled DC-DC Boost Converter for the Operation in DC Microgrid

“…As there are several drawbacks in the hardware implementation of the controller such as lowering of the efficiency, increasing use of hardware components, and power loss [19], and as the output of power sources consists of ripples voltage [20], digital control methods have gained importance for its operational reliability and flexibility [21,22,23]. Current control methods are extensively used in the converters for better performance and simple design [24]. The output voltage of these energy sources alters with the increase of loads.…”

Asymmetric slope compensation for digital hybrid current mode control of a three-level flying capacitor buck converter

“…On the other hand, a digital hybrid current mode (DHCM) control method that combines the ACM and PCM control has recently been introduced for DC-DC converter. Main advantages of this control method are fast response, accurate current control, and overcurrent protection [18]. Similar to the analogue hybrid current mode control [19], there are two current control loops in the DHCM method.…”