Electric vehicle (EV) energy systems (fuel cell, battery, supercapacitor) demand power conversion technologies that can vary voltage based on the load or state of charge. This means operating in a dynamic operating environment such as supplying energy during acceleration and storing it during braking. DC-DC boost converters are a widely used component in the power systems of EVs to step the voltage between input (supply) to output (load) during charge-discharge periods. Traditional voltage/current controls for DC-DC converters utilize pulse-width modulation (PWM) controls. While PWM has worked well in the past, it lacks practical stability range under uncertain operating parameters due to its reliance on linearized models of DC-DC converter dynamics.
To overcome this problem, researchers at UC Santa Cruz have developed a new approach to accommodate the transient behavior and every possible state of the boost converter. By combining two feedback controllers and requisite logic, recent research data suggest broad converter stability even under uncertainty in the input voltage and load resistance. This control framework involves switching between global and local controls, with the global scheme inducing practical asymptotic stability of a desired output voltage (and corresponding current) and the local control scheme maintaining industry-standard PWM behavior during steady state. These preliminary research results hold promise for EV and other systems requiring efficient and high-performance DC-DC conversion.
Patent Pending
electrical circuits, energy, power, hybrid, cyber-physical, electric vehicle, DC-DC boost, PWM, DC-DC convert, asymptotic stability, asymptotic, stability, battery, fuel cell, supercapacitor