Multi Input Multi Output DC Converter

 A dc converter can be used as a dc transformer to step up or step down a fixed dc voltage. The converter can also be used for switching-mode voltage regulators and for transferring energy between two dc sources. The state space averaging technique can be applied to describe the input a

Project Title

Multi Input Multi Output DC Converter

Project Area of Specialization

Electrical/Electronic Engineering

Project Summary

 A dc converter can be used as a dc transformer to step up or step down a fixed dc voltage. The converter can also be used for switching-mode voltage regulators and for transferring energy between two dc sources. The state space averaging technique can be applied to describe the input and output relations of a switching converter, having different switching modes of operation.

Most of the electrical systems are supplied by one type of energy source e.g. utility line power, solar, wind etc. In some cases systems are powered by two sources like UPS (Uninterruptible Power Supplies). In future, most of the systems will need interfacing of different energy sources, among which renewable energy resources will be of specific interest. The interfacing of multiple sources results in improved reliability, flexibility, and utilization of preferred energy sources. In most cases, one source is preferred overall other sources, or a simultaneous combination of different sources is appropriate for optimum economical use. Thus, a multiple input power converter is required. Using multiple inputs, the energy source is diversified to increase reliability and utilization of renewable sources. As most of the renewable energy sources have outputs in the form of DC voltage and every source has its own voltage and current characteristics e.g. Photovoltaic cells, fuel cells and etc. Therefore, a multiple input DC-DC converter is of a practical use.Problem of multiple inputs interfacing for reliable supply can be solved by MISO circuits. There is another problem of loads diversity, different loads operate on different voltages thus multiple outputs are also required. This concludes the requirement of a MIMO DC-DC converter.

The MIMO ensures a smooth switching of power between loads dividing the current of sources which ultimately distributes the power accordingly. The MIMO system mainly depends up on the MISO technology. The design is pretty simple, just there is a need to select an output and find its duty cycle of switch and distribute it accordingly. The greater the voltage, the lesser the duty cycle.Data acquisition system will be implemented to check the efficiency of the system

Project Objectives

In future, most of the systems will need interfacing of different energy sources and loads, among which renewable energy resources will be of specific interest. The interfacing of multiple inputs and outputs results in improved reliability, flexibility, and utilization of preferred energy sources

An attempt to solve the problem of load diversity is taken inconsideration by designing a MIMO converter. The MIMO converter ensures a smooth switching of power between loads dividing the current of sources which ultimately distributes the power accordingly.

MIMO converter is able to accommodate an arbitrary number of sources and loads. The MIMO converter can accommodate multiple input sources and output load and has single inductor which is cost effective

With MIMO converter, the energy source is diversified to increase reliability and utilization of renewable sources can correctly regulate multiple outputs with fast transient response, low cross regulation, and effective switching frequency for each output. It can work in both discontinuous conduction mode (DCM) and continuous conduction mode (CCM).

 MIMO converters are used for the conversion of lower DC input voltage into higher DC output voltage. The MIMO converters are widely used in renewable power generation such as PV and Fuel cell (FC) based system for conversion. Moreover, these converters are used in applications such as automobiles, hoists, trolley cars and mine haulers.

Project Implementation Method

1. Converter circuits will be designed as per load specifications
2. Gate driver circuits for all the MOSFETs will be developed.
3. Controller based PWM signals will be generated for multiple switches
4. Open loop testing of the MIMO converter will be carried out
5. Closed loop system will be designed and implemented for voltage and power quality regulation
6. Economic dispatch algorithm will be run to ensure that all the sources are used optimistically to deliver the required power.
7. Switch losses will be minimized
8. Inductor will be designed to ensure the maximum efficiency of the converter using the high frequency core.
9. Renewable source will be interfaced with MIMO converter using MPPT algorithms.
10. Data acquisition system will be implemented to check the efficiency of the system

Benefits of the Project

Multiple-input multiple-output (MIMO) converters have been identified as a cost-effective approach for energy harvesting and dispatching in hybrid power systems such as those envisioned in future smart homes and DC micro-grids. Compared with relatively complex set-up of single-input single-output (SISO) converters linked at a common DC bus to exchange power, the MIMO converters possess promising features of fewer components, higher power density, and centralized control. Various issues regarding the development of MIMO converters.  Steady-state analysis and dynamic modeling of MIMO non-inverting buck–boost and fly back converters are introduced and presented in detail. Specific switching strategies are proposed and appropriate control algorithms are presented to enable power budgeting between diverse sources and loads in addition to regulating output voltages. Furthermore, a simple method is put forward for deriving the non-isolated MIMO converters with DC-link inductor (DLI) and DC-link capacitor (DLC). Based on a basic structure, a set of rules is listed for the synthesis of MIMO converters. Using the time-sharing concept, multiple sources provide energy in one period, and multiple loads draw energy in the subsequent period. In the end, general techniques are introduced for extending the SISO converters to their MIMO versions, where parts of the conventional SISO converters are replaced with multiport structures. It is envisioned that MIMO converters find their acceptance in the future in various applications with DC distribution, which are becoming increasingly accepted by industry.

A MIMO converter has multiple DC inputs of different voltages and incorporates other MISO circuits to give the multiple outputs. The sole purpose of this type of converter is to run the diversified loads and the block diagram of MIMO converter is shown in Fig. 1. As in DC systems, there are such types of loads which require different voltages and currents to run, so by obtaining different outputs from a single converter, they can be ran successfully.

Recently, micro grids with a combination of different energy storage units and renewable energy sources have changed the research interest due to the environmental considerations and reliability requirement. In such circumstances Multi Port Converters (MPC) play a vital role in interfacing and integrating these energy sources to supply the loads . MPCs can be classified technically into isolated and non-isolated topologies. Each subclass can be further divided into MISO, SIMO and MIMO.Hybrid converters are another group of converters and refer to those which have input ports for AC as well as for DC or the combination of both. In previous few years, a lot of research is done on MPCs. Most of the researchers propose the MISO converter to combine the different energy sources at different voltage levels.

Technical Details of Final Deliverable

A MIMO converter is allowing for users to have input from various sources and thus utilizing them in different types of loads. Typically such converter helps in integrating many sources which directly generate DC power. The implemention of this project is the building block to solve the problem of load diversity in the DC system.

Block Diagram

The MIMO system mainly depends up on the MISO technology. The design is pretty simple, just there is a need to select an output and find its duty cycle of switch and distribute  it accordingly. The greater the voltage, the lesser the duty cycle. All the design will be done like it’s a combination of three MISO converters from the same source. The circuit diagram of getting a MIMO converter by using three MISO converters is shown below.

Circuit diagram of a MIMO system

Predesign parameters

The predesign parameters include the input voltages, output voltages, switching frequency and time period of the switch. The other parameters can be calculated by the equations. A microcontroller board will be used to generate nine PWM switching waveforms.

Duty Cycle

The division of duty cycle is an important point in the MIMO converter design. The duty cycle is divided in inverse relation with the source voltage level which means that higher the voltage of the source, lower is the duty cycle. By using this relation, it is observed that power from highest voltage source will be drawn first.

Values of inductors and capacitors

The values of the inductors and capacitors can be calculate by volt second and ampere second balance. All the inverters will have different values of capacitors because of different currents and voltages and powers as well.

Practical model

The practical implementation of MIMO will be implemented by using STM discovery board or Texas Instrumnents C2000 series controllers. E shaped core will be used for inductors design and fabricatipn at required voltage and curent levels. The PWM scheme will be implemented to control the power electronic swithes in the onverters. Gat driver circuits will be developed for high frequency operatin of the converters.

Final Deliverable of the Project

Hardware System

Core Industry

Energy

Other Industries

Others

Core Technology

Clean Tech

Other Technologies

Sustainable Development Goals

Decent Work and Economic Growth, Responsible Consumption and Production

Required Resources

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