The majority of power losses in solar inverter systems are driven by the root mean square (RMS) DC current in the input loop and the voltage stress imposed on inverter components. The Supercapacitor-Assisted Inverter (SCA-inverter) technique based on the Supercapacitor-Assisted Loss Management (SCALoM) concept, reduces these losses by partitioning the load of a single central inverter into an even number of smaller inverters, integrated with a set of supercapacitor (SC) modules. This approach effectively doubles the inverter system’s input voltage range without having to increase the voltage rating of the components, while halving the input RMS current by a factor of two. This paper presents an experimental efficiency validation of a proof of concept prototype (PoC) of a four-SCA-inverter system and a single inverter delivering the same cumulative power output upto 200W. The proposed technique allows the use SC modules to provide uninterruptible DC power supply (UPS) functionality without having to rely on conventional battery packs.

This paper presents the development of a new Matlab mosfetmodel specifically designed for RLC circuits. The key contribution is the formulation of a novel equation that accurately captures the device behavior across subthreshold, above-threshold regions and at threshold point, addressing limitations in existing models. The developed model treats themosfetas a variable resistance element, with the resistance changing dynamically at each instant, enabling the solution of differential equations governing the RLC circuit. Curve fitting and refinement were conducted based on experimental results, leading to a close match between the simulations and experimental data. The model was tested with triangle, sinusoidal and quadrilateral gate voltages, and the simulation results show good match with the experimental data, demonstrating the model’s accuracy. It provides a straightforward way to predict performance, making it easier to refine and optimize the design gate voltage before physical implementation. This work provides a solid foundation formosfetmodeling in oscillatory RLC circuits, which can be applied to a wide range of power electronics applications.

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.

A novel hybrid energy storage mechanism for portable smart devices that combine supercapacitors and batteries is proposed. Supercapacitors offer rapid charging and high-power delivery, which are ideal for short bursts of power activity, and batteries provide long-term energy storage. The system incorporates a solar energy harvester that efficiently charges the supercapacitor. A unique swapping converter topology allows for quick replacement of depleted supercapacitors with charged ones. This hybrid approach along with the solar harvester aims to extend device operation and reduce reliance on conventional battery charging methods and converters.

Supercapacitor assisted loss management (SCALoM) concept has laid the theoretical foundation to develop high efficiency power converters for renewable energy systems using supercapacitors as lossless voltage droppers and energy buffers. SCALoM theory is applicable to inverter combinations in reducing overall losses, mainly occurring in the input loop, including losses in the DC bus capacitor.Supercapacitor assisted (SCA) multi-inverter technique reduces the voltage stress on the internal components of inverters enabling the use of more efficient lower voltage rated components. A summary of the theoretical foundations with reference to previous works on the topic is presented first. The four-SCA-inverter technique discussed in this paper extends the input voltage range of an inverter system by two times and reduces the input loop current by two times. The preliminary results obtained from the first experimental prototype of the 700W four-SCA-inverter system coupled with four identical 250F supercapacitor modules switched at low frequencies (less than 0.02 Hz), show up to 2.53% of efficiency gain at the inverter end. Additionally, proposed technique provides unquantified efficiency gains by reducing the ripple currents in the system, functioning as an energy buffer. Development of a high power capable SCA-inverter prototype is in progress.

High-voltage pulse generators are useful in many applications such as transient surge simulators, electric fence energizers, and transcranial magnetic stimulation (TMS) systems. Traditionally they are based on a high-voltage DC power supply with or without voltage multipliers for raising the voltage to several thousand volts. In contrast to these complex and costly approaches, we use a pre-charged supercapacitor followed by a step-up transformer and associated output circuitry to develop an inexpensive and flexible high-voltage pulse generator for applications in transcranial magnetic stimulation. Our new approach is to use the high-power delivery capability of commercial supercapacitors. In this work, we explore the advantages of different waveforms applied to the MOSFET associated with the secondary stage of the circuit topology and how they affect the final pulse shape.

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.

High power pulse generators with variable parameters are helpful in many applications in the industrial and medical fields. The traditional approach to design these pulse generators is to start with a high voltage DC power supply, energy storage capacitor, and a wave shaping circuit. However, building a high-voltage DC power supply itself is a complex task and it ends up in a complicated circuit with several high-voltage components hence adding to the total cost. This paper presents a unique new approach to designing a supercapacitor-based high-voltage pulse generator with a lower number of components and simple two-winding transformer. First experimental circuit developed based on this new approach is presented here with variable pulse generator capable of several hundred volts peak voltage with loop current capability of several hundred amperes.

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.

SCASA is a new supercapacitor assisted surge protector technique whose goal is to reduce component count in surge protectors while achieving higher surge-withstand capability. Basic topology was developed based on a semi-experimental basis, during the first stage leading to patents and a successful commercial implementation. This paper summarises a numerical analysis applied to the basic circuit to compare and validate its performance with experimental results using a lightning surge simulator and LTSpice simulation. Noiseken LSS6230 was used as the test gear to do the testing according to IEEE C62.4X standards and UL 1449 test procedure. This comparison is used as the basis for further improvement of SCASA topology to withstand higher energy and increased surge repetition.

The supercapacitor-assisted low-dropout (SCALDO) regulator is an extra-low frequency technique for designing high efficiency, low noise, step-down DC-DC converters with a supercapacitor (SC) energy circulation front-end in series with an LDO regulator. Due to the nature of the SC switching network at the front-end, one can tend to consider the SCALDO technique as a variation of a charge pump topology. The scope of this paper is to compare the major topological differences of the SCALDO regulator and the step-down charge pumps and hybrid-charge pump converters. The operation principles of conventional step-down switched-capacitor DC-DC converters are described, their limitations are identified, and the advantages of hybrid charge pump converters are also highlighted. Then, the SCALDO concept is discussed in detail. The topological differences of the SCALDO and charge pumps are identified, and the performance characteristics are compared concerning the output current driving capability, operating frequency, switching ripple, efficiency, power density, and complexity.

Supercapacitor-assisted low-dropout (SCALDO) regulator technique is gradually developing as a novel design approach for high-efficiency, low-frequency DC-DC converters. This technique increases the end-to-end efficiency while maintaining the useful benefits of a linear regulator such as the low output noise, fast dynamic response, and less electromagnetic interference (EMI) and radio-frequency interference (RFI) issues. It is essential in SCALDO regulators to have primary circuit protection measures to safeguard the converter and the output load during external conditions such as overcurrent, overvoltage and undervoltage. This paper provides an insight into applicable circuit protection techniques so that SCALDO regulator designers can integrate them to make a robust design. The proposed protection techniques are tested on a 12–5 V discrete component-based SCALDO regulator developed in MATLAB SIMULINK simulation.

To extract the maximum power from a photovoltaic (PV) system, the maximum power point (MPP) of the PV array must be tracked continuously. A directly coupled load with the PV array does not track the MPP of the PV array because the load has a constant resistive value. Therefore, to track the MPP of the PV array, a technique called impedance matching is used. This is done by continuously matching the load impedance to the instantaneous impedance of the PV array. Switch mode DC-DC converters are widely used for this purpose which also helps to interface the DC output of the PV array with power distribution systems in order to deliver the power to the consumer end. However, the efficiency of these converters lies around 90% which degrade the end to end efficiency of the PV system. In this context, novel supercapacitor (SC) assisted PV systems have been introduced, which were able to enhance the end to end efficiency of PV systems. However, existing impedance matching technique is no longer valid for SC assisted PV systems. Therefore, still it is a challenge for these systems to track MPP of the PV array continuously while in operation. This paper presents a study on impedance matching technique for the novel SC assisted PV systems. Previously, it has been experimentally shown that a series connected SC bank between PV array and DC-DC buck converter of a PV system could deliver higher end to end efficiency than typical systems. This study validates the impedance matching technique for SC assisted PV systems by connecting a SC bank in series with buck, boost, and buck-boost converters. Simulation results indicate that this can be achieved by carefully designing the system with given parameters.

Supercapacitor (SC) assisted low dropout regulator (SCALDO) is a very low-frequency DC-DC converter technique, with high end-to-end efficiency, where the load receives a high slew rate capable low noise output of a linear regulator. This technique can be easily extended with a transformer isolated input stage to achieve the 48-V DC rack power architecture proposed by Google recently. One specific advantage of this new design approach is the two-stage DC-UPS capability by over-sizing the SC bank. In this new SCALDO-derived technique with transformer isolation, by inserting an SC in the input side of the converter, energy transfer towards the load side occurs at a higher frequency, in a combination of forward and flyback modes to reduce the overall volume of the converter. The paper details the magnetics design aspects of the technique providing experimental results of a proof of concept prototype.

Typical solar powered DC-microgrids (DCMG) employ rechargeable batteries for energy storage. In order to extract and deliver the maximum power out from the PV array to the load, maximum power point tracking (MPPT) solar charge controller is mandatory. With the commercial supercapacitor (SC) devices available in the market, new converter techniques with SC energy storage are possible for DCMG systems. The SCALED converter is such a technique where the rechargeable battery bank is replaced by a supercapacitor bank. However, if a SC bank is used as the sole energy storage, existing MPPT schemes are no longer appropriate since the storage bank acts as near ideal capacitor instead of a rechargeable battery pack. This is due to the fact that a capacitor bank retains energy within its electrostatic field, compared to the electrochemical reaction related back EMF of a battery pack. This paper presents the theoretical analysis to validate the above hypothesis.

Energy efficiency of power converters used in computer server farms is a major issue today since these facilities consume huge amounts of energy on a continuous basis. In 2016, Google introduced a 48 V rack power architecture at the Open Computing Project (OCP) summit to replace 12 V, and announced their plans to shift towards 48 V DC rails with DC-UPS. This was with the main target of reducing ohmic losses in the DC-distribution by 16 times and transformer losses by 30%. Compared to well-developed switching converter techniques, a new linear high efficiency RFI/EMI free DC-DC converter technique, namely SCALDO, has the potential to be used for these 48 V DC server power supplies. This paper presents analytical and simulation details of an electrically isolated, 48 V DC, 20 A extended-SCALDO based design. Experimental validation of this technique has been established by developing a proof of concept prototype, a scaled down 30-to-6-V DC converter. The paper highlights the advantages of combining the fly-back and forward modes similar to a switching converter, for charging a supercapacitor bank which acts as energy reservoir, where the final 48 V DC rail is regulated by a simple SCALDO converter extended to supply 20 A, and achieving DC UPS capability by over-sizing the supercapacitor.

In configuring energy-efficient renewable energy systems, rechargeable batteries are typically used with maximum power point tracking (MPPT) based DC-DC converters. With the commercial supercapacitor (SC) devices available in three different forms namely (i) symmetric electrical doubled layer capacitors (EDLC) (ii) hybrid and (iii) capa-batteries, where device cycle-life is exponentially larger than rechargeable batteries, new converter techniques with SC energy storage are possible for DC Microgrid systems. This paper presents the preliminary concept of a new and commercially-useful SC-based LED powering technique, currently under development as the SC assisted LED (SCALED) technique. Challenges of developing this technique which can be extended into the powering of DC powered electrical appliances is presented with the theory and early experimental validations carried out in a sea-port based industrial location.

Electrical physics text book theory tells us that charging a capacitor is much less efficient than replenishing the energy in a discharged electro-chemical battery. If a fully discharged capacitor is pumped with a charge of Q coulombs, it stores 1/2QV while dissipating the same amount of energy in the loop resistance. However, if the same charge is pumped into a re-chargeable electrochemical cell of voltage V the energy stored in the cell is QV, while the wasted energy is determined by the loop resistance and the voltage difference across the resistance. If a rechargeable battery pack is to be replaced by a supercapacitor module, this difference could seriously affect the design of power converters required, since the power converter should stop charging at a certain point to avoid overcharging the capacitor bank. However, if a useful resistive load such as heater, DC-DC converter, inverter or a lamp load is used as a part of the loop resistance in a capacitor charging loop, a significant part of this loss can be recovered. One example of this is in the supercapacitor assisted low drop-out regulator (SCALDO) technique. This paper will detail the concept of circumvention of RC loop charging loss, theoretically quantifying the same in a generalized circuit, demonstrating how this can be applied in completely novel circuit topologies such as the supercapacitor assisted LED (SCALED) converter. The paper will provide experimental results of selected SCALDO implementations and early results of SCALED technique to support this theory.

AC voltage regulators, an important family of power conditioners, are intended to reduce line-voltage fluctuations of AC mains at customer premises. Typical designs are based on automatic tap changers, motor-driven variacs, thyristor-based systems, ferro-resonant systems and solid-state versions. Solid-state regulators typically rely on high frequency switching, so have significant RFI/EMI problems, while ferro-resonant regulators are bulky, have high no-load power consumption and waveform defects. Thyristor-driven designs are light in weight, but also have waveform defects. Motor-driven variacs are slow-responding, while automatic tap changers create spikes. A linear design using an array of serially connected transistors was developed in late 1980's to address these issues, and to achieve rapid output response without requiring thyristors, high-frequency switching or mechanical systems [1], [2]. We have built on these ideas to develop an AC voltage regulator for consumer use, with a power output ranging from 500 to 3000 W. A multi-primary-winding transformer design was originally proposed, but was found to be uneconomical due to manufacturing costs. The simple approach is to combine two standard step-down transformers. The viability of this approach demonstrated with practical results for a scaled down prototype which can be scaled up to a full 230 V, 2 kVA commercial product. Energy efficiency is optimized by minimizing the losses in the transistor array.

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.

Their combination of large continuous energy ratings and very large time constants allows supercapacitors to be used in surge protection circuits. This fact, supported by recent research publications and laboratory tests, has assisted the authors to propose a new surge protection circuit topology known as the supercapacitor-assisted surge absorber (SCASA). This technique utilizes a multi-winding transformer, common surge protector devices such as metal oxide Varistors (MOV) and/or semiconductor types combined with a supercapacitor sub-circuit to absorb part of the surge energy usually expected to dissipate within the MOV or the semiconductor. The paper presents design details and test results for a differential mode surge protector based on the SCASA technique where the test device was subjected to lightning-type surges defined in international standards for Class-A and Class B type protectors. The performance of a prototype based on Class-B waveforms of up to 6.6 kV surges generated from a lightning surge simulator are discussed in the paper. Its performance is compared with two commercially available surge protectors.

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.

A supercapacitor-assisted low-dropout regulator (SCALDO) technique has been developed previously to improve the end-to-end efficiency of linear regulators based on low-dropout regulators. To implement this technique in a high-current application such as a voltage regulator module (VRM), it is necessary to reduce the number of low-speed switches used in SCALDO topologies. A preliminary prototype of a modified SCALDO version has been built with commercially available low-dropout regulators to prove the concept of reduced-switch SCALDO. One limitation of this reduced-switch SCALDO prototype was the unwanted discharge of supercapacitors via body-diode of low-dropout regulators. Experimental results indicate that the reduced-switch SCALDO can be further developed for application to VRM by suitably designing a high-current low-dropout regulator. This paper presents the theoretical aspects of the reduced-switch topology, a new approach to avoid the low-dropout regulator body-diode effect on supercapacitors, and a method to optimize the control circuits. The preliminary results of a custom-designed 1.5 V, 2 A discrete low-dropout regulator and a 3.5-to-1.5 V reduced-switch SCALDO converter are presented.

With the transformer less direct AC mains rectification adopted in many AC-DC converters for processor based products, many electronic components in off-the-line switchmode power supplies are vulnerable to common-mode transients. With the predictions in the International Technology Roadmap for Semiconductors, VLSI devices are currently progressing towards feature sizes around 22 nm, with sub 1 V DC power supply requirements and equivalent noise voltages close to the DC rail values. These two scenarios make state-of-the-art systems seriously vulnerable to lightning and other power transients, and better transient protection systems are required by the power conversion electronics. In a research project to predict the propagation of transients within the power conversion interfaces, accurate models for nonlinear surge protection devices have been developed. This paper highlights the numerical simulations done with the help of MATLAB to investigate transient propagation through an IEC61000-4-5 specified category “B” protection unit. The accuracies of the simulations are confirmed by experimental validations using a lightning surge generator.