Over the past several decades many researchers have attempted developing DC circuit breaker techniques, recognizing that a DC current loop does not have voltage or current zero crossings across the contact terminals, in comparison with an AC circuit where voltage and current waveforms carry two zero crossings per each cycle. All DC circuit breaker design efforts are based on several primary techniques such as (i) mechanical (ii) solid state and (iii) hybrid. However, commercially useful techniques or prototype development has been limited to mechanical only approach with the adoption of 3 phase AC circuit breakers where three separate contacts are placed in series to share arc energy. Solid state and hybrid design approaches require DC power supplies, transistor driver stages and synchronization circuits which makes the prototype development very cumbersome. As a uniquely different approach, authors have started working on supercapacitor assisted techniques for arc energy management and this article presents corresponding preliminary findings with some experimental evidence.

DC circuit breakers have become an essential protection element for DC buses in renewable energy and DC microgrid systems. Given that there are no zero crossings in a DC power supply compared to an AC waveform, arc extinguishing is a difficult process in DC circuit breakers. Solid state switches are proposed in solving this problem, but their cost is generally unaffordable in general applications, except for marine, military and aviation etc. Hence, commercial and mass-produced DC breakers are modified versions of AC breakers. This paper details different passive component options for absorbing the energy in the electric arc/plasma, including the use of supercapacitors.

AC circuit breakers are a mature technology, and are based on an arc chamber coupled with inductive arc absorption circuitry developed using commercial off the shelf components. In developing these, two zero crossings per AC cycle is effectively used, with capacitors, MOVs and other components used at the switch contacts to absorb the inductive energy in the AC circuit loop.Given that a DC circuit loop does not provide current zero crossings, arc extinguishing is not supported. Hence, commercial DC breakers are modified versions of AC breakers, usually the contacts of a 3 phase breaker poles connected in series to share the arc energy, sometimes combined with other transient absorbing components.This paper presents a preliminary results of a new approach for DC circuit breakers based on placing a supercapacitor based energy absorption loop, making use of the high current capability and the significant joule rating of a supercapacitor.

Charging a capacitor is different to supplying power to a resistive load. With an ideal voltage source a fully discharged capacitor takes five time constants to reach its full charge. From a current source this depends on the current rating. Therefore a capacitor charger can be characterised by the associated total charge. Due to supercapacitors' (SC) large time constant fast charging becomes problematic. The charging topology presented uses a coupled inductor and a voltage source rated higher than the capacitor rated voltage to charge a SC bank divided in to two parts. One part is charged by the higher voltage source and the other by the energy stored in the inductor. Power factor correction can be achieved without using any additional components. This paper presents results from a 3000 joule proof of concept prototype.

A hybrid energy source allows a designer to meet extraordinary application requirements without having to make any performance sacrifices [1]. Most available hybridisation techniques in the literature are applied to automobile applications, describing solutions to pulsed load profile characteristics [2]. This study involves an instant water heater having a load profile of 18kW to 25 kW for 30s to 60s repeating once every 15 min, which cannot be modelled as a pulsed power application. In a commercial product development process, where the total product cost has to be kept low, the present cost of supercapacitors (SC) requires the application of battery-SC hybridisation, with an aim to lower the cost of SCs, without compromising the battery life [3]. This paper presents hybrid power source design options for a representative instant water heater system along with simulation and experimental results.

Delayed hot water in domestic water heating systems is a worldwide problem. In New Zealand, it accounts to over a 15 million cubic meters of treated water wasted per year. There are few commercial solutions proposed to minimize the problem, but none of them are affordable or practically convenient. To increase the temperature of stored water in buried pipes by 20–30 °C at an average flow rate of 5–8 1/min estimated power is over 15 kW. The circuit breaker in a 230V/50 Hz, 10 A domestic sub-circuit creates a barrier for this application to be solely powered from the 230 V mains. A supercapacitor based high-kW pre-stored energy transfer system can solve this environmental issue of wasted water and the repeated frustration in the kitchen or the wash rooms on a daily basis. This paper provides the fundamental justification for such a low-voltage electrically-safe short duration localized in-line water heating solution with high instantaneous power capability. Initial test results of a proof of concept prototype, with "fast-energy-delivery, replenish-gradually, and ready-to-go" basis design shows the effectiveness and the practicality of the supercapacitor solution, leading to a commercial product design.