**5.3 Implementation and testing**

330 Grid Computing – Technology and Applications, Widespread Coverage and New Horizons

documented method for verifying and validating of design before move to the development in actual controllers and hardware (Woodward and Mosterman, 2007 & Manfred, 2006). System engineers usually develop this high-level description for several purposes as listed below:

2. It is used throughout the development process for testing, verification and

3. It allows for developers to identify bugs early on and avoid costly bug discovery

4. It eliminates the need for paper-based specifications, which is easily prone to

5. Each member of a design team can understand and execute the model and can focus in developing parts of the main model (Madhukar and Lee, 2008 & Ming-Shan, 2007). A key point of shrinking the embedded life cycle by applying the MBD method is to begin developing the embedded control algorithm early in the design cycle as possible (Rautio, 2008). In this stage, the model provides the ability to begin simulation of the control behaviors while the hardware prototype is still under development. In addition, the model can be re-used for further modification of the same product which reduces the effort

When designing the executable specification, the system engineer generally does not keep the implementation details in mind, but rather designs the algorithm to match the

1. It enables designers to perform simulations by directly executing the model.

misinterpretations, and replaces it with the executable specification.

Fig. 2. Elements of Model Based Design

towards the end of development.

necessary to build the model again.

**5.2 Design with simulation** 

implementation.

The modern Model Based Design tools provide automatic generation for both prototype and production codes directly from the model. So, all the design changes automatically flow through the final implementation. This process results in significant time and cost saving due to the inherent reproducibility and testability of the generated codes and elimination of communication errors (Ming-Shan, 2007 & Rautio, 2008). In the Hardware In the Loop (HIL) Testing, the designer can test the real-time behaviors and characteristics of the final system to verify the system control without the need for the physical hardware or operational environment, as shown in Figure 3. HIL Testing can save the time with significant ratio comparing to the traditional design method. As well, it is easy to implement comparing to physical prototype production. Up to this moment, the Model Based Design process does not completely eliminate the need for testing in the actual prototype, but it offers several opportunities to reduce the time needed to the testing stage (Stepner et al., 1999 & Mosterman, 2010 & Behboodian, 2006 & Davey and Friedman, 2007).

Fig. 3. Hardware In the Loop (HIL) Testing

Potential of Grid Technology for Embedded Systems and Applications 333

In this application, the operation of the electric circuit is controlled by the embedded system that includes the SH microprocessor and the embedded software. Development of the embedded software faces many challenges when using the traditional design method.

The first step of the inverter power supply is to step up the DC voltage level which comes from a battery to higher DC level by using the DC/DC converter. DC/DC conversion revolves around the conversion of DC voltage level which comes from sources such as batteries, solar panels, fuel cells, or wind generations to a higher DC level. There are many different types of DC/DC converters, and each of which tends to be more suitable for some types of application than for others. For convenience, we can classify them into various groups. For example, some converters are only suitable for stepping down the voltage while others are only suitable for stepping it up; a third group can be used for both cases of stepping up and stepping down the voltage. Another important distinction among converters is which one offers full dielectric isolation between their input and output circuits. Dielectric isolation behavior may be important for some applications, although it may not be significant in many others. In this section we are going to look briefly at each of

 Non-isolating converter: The non-isolating type of converter is generally used where the voltage needs to be stepped up or down by relatively small value (less than 4:1), and there is no problem with the output and the input having dielectric isolation. Examples are the 24V/12V reducer, 5V/3V reducer, and 1.5V/3V step up converter (Mohan.N,

 Isolating converters: In many applications, the non-isolating converter is unsuitable where the output needs to be completely isolated from the input. Isolated converter topologies can provide advantages in applications which require large voltage conversion ratio. The transformer in the isolation type DC/DC converter can reduce switch and diode device stresses and allow multiple windings or taps to be used for multiple converter outputs

In this study, the isolation type DC/DC converter is used in the inverter power supply

The full-bridge is a popular design for both buck and boost applications. It is one of the simplest and most cost-effective configurations. Another advantage for using the full bridge converter is the fact that when higher power application are requested the full bridge converter can act as a modular block and that it is possible to stack up. For this purpose, the chosen topology for the converter to be used in this application is a full bridge phase shifted

the main types of DC/DC converter in the current use as presented below:

(Mohan. N, 1995). Here are some examples of isolating converters:

implementation. Figure 5 shows examples of the isolated converter.

**6.1 DC-DC conversion** 

1995). There are five main types:

c. Full Bridge DC-DC converter.

PWM converter (Mohan. N, 1995).

1. Buck converter; 2. Boost converter; 3. Buck-boost converter; 4. Cuk converter; and 5. Charge-pump converter.

a. Half Bridge; b. Push-Pull; and

Generally, it can be concluded that the Model Based Design method will reduce the number of the development stages by combining the design, implementation and testing into one process. The reduction of the required step comparing to the traditional method of design will result in better project management and mitigate the system development risk. The system design using this approach will reach the market faster and will cost less than that of the system designed using the traditional method. Subsequently, the use of the MBD method can provide numerous advantages over the traditional design method. Therefore, this study investigates how the Model Based Design method can provide such advantages by applying and building a new virtual environment for the embedded system design. Inverter power supply is used as a case study of the embedded system in this research.
