Boost Dual-Loop Control Model

The boost dual-loop control model is a widely adopted control strategy in switched-mode power supplies, particularly suitable for boost converters operating in Continuous Conduction Mode (CCM). This model achieves precise output voltage regulation and fast dynamic response through coordinated operation of an outer voltage loop and an inner current loop. In code implementation, this typically involves nested PID controllers with appropriate sampling rates and anti-windup protection.

The outer voltage loop monitors the output voltage and compares it with a reference voltage to generate an error signal. This error signal is processed by a Proportional-Integral (PI) regulator, which outputs a current reference value serving as the input target for the inner current loop. The primary function of the voltage outer loop is to maintain stable output voltage at the set value, ensuring excellent steady-state accuracy. Algorithm implementation typically uses discrete PI control with code structure including error calculation, integral accumulation with clamping, and proportional gain multiplication.

The inner current loop tracks the current reference signal provided by the voltage outer loop, controlling the inductor current by adjusting the switching transistor's duty cycle. The inner current loop typically responds much faster than the voltage outer loop, which helps suppress disturbances caused by input voltage fluctuations or load variations, thereby enhancing system dynamic performance. Code implementation often involves high-frequency sampling of inductor current, rapid PWM duty cycle adjustments, and may incorporate current limiting protection algorithms.

In CCM mode, where inductor current remains continuously above zero, controller design becomes relatively straightforward though attention must be paid to potential issues like subharmonic oscillation. Implementation considerations include proper slope compensation in the control algorithm and careful tuning of loop bandwidths. The dual-loop control structure's advantage lies in balancing steady-state accuracy with dynamic response while improving system disturbance rejection capability.

This control model finds extensive applications in renewable energy generation, battery charging systems, and DC-DC converters, representing one of the fundamental control strategies in power electronics. Typical software implementation involves structured state machines, ADC configuration for voltage/current sensing, and PWM peripheral control with dead-time management.