Academic literature on the topic 'Independent metering, mode switching, energy efficiency'

In order to meet the growing demands of electricity, it is imperative to increase the efficiency of distribution system and reduce all wastage of energy. In this paper, the data from the distribution companies and regulatory bodies are analysed to identify the inefficiencies existing in the electricity distribution to the agriculture consumers of the state of Gujarat in India. The primary causes for the inefficiencies in the system are absence of effective monitoring and correct and reliable data on the usage of electricity by agricultural consumers, and the technical loses of electricity on account of low Power Factor and poor voltage regulation. The paper proposes a comprehensive solution to address the identified problems by way of installing a Metering Reactive Compensation Unit (MRCU) independent of consumers’ energy meters. MRCU will contain capacitors for reactive compensation, relay and switching unit, metering unit for current, voltage, Kilowatt, KVARH and KWH, and LORA based communication module for 24x7 data capture. The data captured at the cloud level will be analysed by a head end software system for real time reports and corrective actions. The estimated monetary benefits from installing MRCUs for entire Gujarat’s agricultural consumers is estimated to be Rs 1500 Crore in a year, apart from an estimated energy saving of close to 2000 MUs per year.

This paper provides an exhaustive analysis of the Dual-Active-Bridge with Triple-Phase-Shift (DAB-TPS) modulation and other simpler ones, identifying all the possible switching modes to operate the DAB in both power flow directions, and for any input-to-output voltage range and output power. This study shows four cases and seven switching modes for each case when the energy flows in one direction. That means that the DAB operates up to fifty-six different switching modes when the energy flows in both directions. Analytical expressions for the inductor current, the output power, and the boundaries between switching modes are provided for all cases. Additionally, the combination of control variables to achieve Zero-Voltage-Switching (ZVS) or Zero-Current-Switching (ZCS) is provided for each case and switching mode, by showing which switching modes obtain ZVS or ZCS for the whole power range and all switches—independent of the input-to-output voltage ratio. Therefore, the most interesting cases, switching mode and modulation for using the DAB are identified. Additionally, experimental validation has been carried out with a 250 W prototype. This analysis is a proper tool to design the DAB in the optimum switching mode, reducing the RMS current and achieving to increase efficiency and the power density.

In this paper, two light-load efficiency improvement methods are presented and applied to the ultrahigh step-down converter. The two methods are both based on skip mode control. Skip Mode 1 only needs one half-bridge driver integrated circuit (IC) to drive three switches, so it has the advantages of easy signal control and lower cost, whereas Skip Mode 2 requires one half-bridge driver integrated circuit IC, one common ground driver IC, and three independent timing pulse-width-modulated (PWM) signals to control three switches, so the cost is higher and the control signals are more complicated, but Skip Mode 2 can obtain slightly higher light-load efficiency than Skip Mode 1. Although the switching frequency used in these methods are reduced, the transferred energy is unchanged, but the output voltage ripple is influenced to some extent.

<span>This work presents a design and development of a remote controller application using an Altera DE2-115 board. A remote controller lighting provides smart technologies make it viable to monitor, control and support users in which can enhance the quality life and promote independent living. Nowadays, to turn on the electrical devices, a user will go to the located switch. It is difficult and required more time to switch on the devices instead of staying at certain location while controlling the switching mode of the devices. Implementing this system, users do not need to have numerous switches in their home to turn on the lights as they can do this digitally from a switchless control located in one place or using a remote controller. The Altera board is built with eighteen slide switches which act as inputs and at the same time it will display the outputs on seven segments, LEDs and LCD display character. As a conclusion, the remote controller lighting system provides convenience and energy efficiency in order to allow the users to control the lighting system using smart devices. </span>

As being restricted by factors such as cost, efficiency and size, the development of high-power solar LED street light controller is faced with plenty of difficulties. In case that a structure of two independent DC/DC is applied as the main circuit, it has to face problems such as large size and high cost; in case of applying the bidirectional BUCK/BOOST circuit, it requires change-over switches to control the solar panel and LED light. As being restricted by withstanding voltage, on-resistance and cost, a PMOS device cannot be used as the change-over switch of solar panel and LED light. However, when being used as a change-over switch, an NMOS device must apply the low-side mode under which the negative ends of the mentioned three parts are cut off. In the condition of applying the low-side mode, a differential circuit must be used to detect the voltage of the solar panel. Furthermore, in order to make sure batteries can still be regularly charged after wearing out in daylight, the controller must be supplied with power through a dual power supply circuit that can obtain power from both the solar panel and the battery. The demander has a requirement on extremely low standby power consumption of the product, and thus it is necessary to minimize the circuit that is live while working in standby mode. Methods: The bidirectional BUCK/BOOST circuit structure is applied to the main circuit to realize a higher change-over efficiency while giving considerations to both cost and size. The NMOS device, model IRFB4410ZPBF, with a price of about three yuan, is used as the switching device, and the low-side mode is applied, that is the switches inserted in between negative end of the solar panel or LED light and that of the DC/DC circuit. The low-cost rail-to-rail operational amplifier LM358 is used to form a differential amplification circuit for detecting the voltage of the solar panel. A XL1509-12E1 chip that only costs 0.88 yuan/pc is selected as the main change-over chip for the power supply, which has realized the highly-efficient and low-cost change-over of the power supply. A dual power supply circuit and a step-down protective circuit are designed for the XL1509-12E1 change-over chip. By comparing solar panel voltage with battery voltage, the solar panel booting circuit is realized. Only when solar panel voltage is higher than battery voltage, does the system program start to power it up for running, so that the outage of most of the circuits of the system under standby mode does not consume energy. Furthermore, the solar panel voltage detecting circuit, the solar panel booting circuit and several return difference functions are corrected during system debugging. Results: The circuit board of the entire controller features small size, low cost and high efficiency. It measures about 100*62*18mm in size, costs about 60 yuan, and the charge/discharge change-over efficiency reaches up to over 95%. The controller has many functions: it is capable of operating within a large scope, in which, solar panel voltage is subject to 15~50V, LED light voltage is subject to 15~60V, battery voltage is subject to 10~35V and battery-end charge/discharge current is 10A; it is capable of adapting to monocrystalline silicon/multicrystalline silicon/thin-film and many other kinds of solar panels, as well as lithium/lead-acid and many other kinds of batteries; it is capable of detecting the conversion of day and night, automatically controlling charging and discharging and automatically making adaptive adjustment according to seasonal variations; the current to be consumed during standby will be maintained below 3mA, and thus the power consumption is extremely low. Conclusion: By selecting the bidirectional BUCK/BOOST circuit structure, applying low-side mode for switching of solar panel and LED light, using a differential circuit to detect solar panel voltage, using a low-cost DC/DC chip to realize power supply change-over, designing a dual power supply circuit, introducing solar panel booting circuit and other hardware design, as well as MPPT algorithm, state recognition and control, return difference control and other software design, a solar LED street light control product featuring small size, low cost, high efficiency and multiple functions is successfully developed.

This study applies independent metering control in a forestry forwarder in order to improve its energy efficiency. The paper describes the control method, which enables smooth control mode switches and relatively accurate velocity tracking without position, velocity or acceleration feedback. The energy saving capability is analysed through measured, realistic, working cycle, which is repeated for the baseline system and independent metering system. The input energy taken by the control valves is compared. Furthermore, the power losses of the supply pump and diesel engine are modelled to achieve semi-empirical estimate for the diesel fuel consumption. The results show an average reduction of 25% in the fuel consumption when compared to the baseline.

Independent metering poses a possibility to improve energy efficiency of throttlecontrolled hydraulic single-rod cylinder drives. This paper deals with energetic potentials gained through variable circuitry that come along with independent metering. A method to assess energetic potentials is described, based on load specific, optimal operating modes. As a means of yielding maximum energy efficiency for a wide range of applications, a smooth mode switching algorithm that minimizes losses and allows good motion tracking is proposed. The mode switching algorithm is validated in simulation and on a test stand.

Independent metering valve systems open up for more flexibility because of the ability to control meter in and meter out flow individually, thus enabling many possibilities to adapt the actuator s behaviour to the user´s needs without altering any hardware. Furthermore, with alternative flow modes significant energy savings are possible. In many applications like excavators smooth switching between flow modes is required, a demand the market does not provide a satisfying solution for yet. Here, an approach using a short circuit path for smooth switching has been developed. The control algorithm hands over the volume flow from one path to another continuously depending on the current actuator load. Due to the flexible software structure the developed control algorithm can be applied to a very broad variety of independent metering valve layouts. Simulation results are promising and currently the solution is undergoing test rig evaluation.

Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2007.<br>Wayne J. Book, Committee Chair ; Nader Sadegh, Committee Member ; Chris Paredis, Committee Member ; Bonnie Heck, Committee Member ; Roger Yang, Committee Member ; Renato D.C.Monteiro, Committee Member.

Valve controlled cylinder drives are an obvious choice whenever high loads are manipulated in translational motion with demanding requirements in terms of dynamic properties, accuracy, and costs. Improvements of energetic efficiency of valve control can be achieved by separating metering edges, allowing for different operating modes and thus adapting to different load scenarios. In this paper, multiple-input-multiple-output closed loop control approaches are investigated in order to control cylinder speed and pressure in one cylinder chamber for a configuration with five 2/2-directional valves. By utilizing the flatness property of the system, the flatness-based tracking controller and the flatness based internal model controller will be described, developed and tested. They are adapted to the excessive number of command variables by introducing extended input. Based on validation on a test rig, the characteristics of both control approaches are pointed out. The control strategy is fitted to a smooth mode switching algorithm published by the authors previously. It is shown that by making use of the degrees of freedom involved in the presented system, different operating modes can be switched smoothly in closed loop control. This contributes to the applicability of energetic potentials of independent metering.

To decrease throttling losses in mobile hydraulic systems a number of new system architectures have been introduced in recent years. The concept of independent metering (IM), developed in the seventies, shows a lot of promise [1]. By allowing the meter-in as well as meter-out edges to be controlled separately, additional operating modes are created allowing a more efficient adaptation of system pressure to load pressure [2, 3]. Despite these advantages IM circuits have yet to find their way into industrial applications. This is mainly due to the related increase in component costs and more demanding control strategies. Additionally, the effect of mode switching on actuator motion and operator comfort is still unclear and considered to be a challenge. The STEAM mobile hydraulic system currently being developed in Aachen, Germany uses a number of new features to improve total machine efficiency [4]. Among others is the use of a new independent metering circuit called single edge meter-out control. Unlike other IM configurations, only one proportional valve is used to control cylinder motion. This paper introduces the new concept and discusses its advantages.