**8. Experimental results**

Actual prototype of inverter power supply has been fabricated using Renesas SH microprocessor. The output voltage and the frequency of the inverter power supply are verified and the responses of the inverter power supply in the existence of loads are checked to confirm the efficiency of the control algorithm. Some of the results are shown below in Figure 22.

Fig. 22. Output of inverter power supply: (a) Actuals (b) Simulation

Potential of Grid Technology for Embedded Systems and Applications 351

parameter. Various techniques are used to compensate the effect of the voltage drop in the inverter power supply design. One of the main techniques is to apply the control system. The main duty of the inverter control system is to regulate the output voltage against the entire possible disturbance and the load variations. As mentioned before, the two layer control algorithm which consists of the feedback PI controller plus the feed-forward controller is proposed to control the inverter power supply. The validity and usefulness of this controlling algorithm are tested in the existence of linear load. Figures 24 and 25 show the output of the inverter power supply with no load and after connecting the load resistance Rl = 60Ω respectively. From Figure 25, we can see the voltage reduction at the moment when the resistance is connected but due to the control algorithm, the voltage can return to its value within a very short time. We can conclude that the proposed control algorithm is able to modify the distortion that occurred due to the load in a very short time. So, using the control algorithm can improve the inverter power supply's performances.

Fig. 24. Inverter power supply output with no load

Fig. 25. Inverter power supply output with no load in the MILS

One of the effective parameters of the inverter power supply is the time it can reach its stationary value. Figure 22 describes this parameter and it is clear that the shapes of the wave are visually identical. We can conclude that the developed models can simulate the actual prototype in a good way within very short time comparing to the traditional method of design. The output voltage and frequency are tested, as shown in Figure 23 as well as the relationship between the output waves and the generated PWM signals which are generated by the microprocessor and controlled by the embedded software.

In Figure 23, comparing the two waveforms, it can be seen that the result obtained by the developed model is in a good agreement with the actual result in both frequency and voltage amplitude. It is apparent that the narrow pulse is generated when the modulating signal is at its maximum or minimum values.

(b) Simulation

Fig. 23. Sin wave output of inverter power supply:

#### **Response with linear load**

The inverter power supply output distortion or the output voltage drop is considered a very important issue in the design of the inverter power supply. There are many regulations regarding the allowable voltage drop in the inverter power supply. For example, based on the standard IEC686, the allowed voltage drop is no more than 5% voltage against single 350 Grid Computing – Technology and Applications, Widespread Coverage and New Horizons

One of the effective parameters of the inverter power supply is the time it can reach its stationary value. Figure 22 describes this parameter and it is clear that the shapes of the wave are visually identical. We can conclude that the developed models can simulate the actual prototype in a good way within very short time comparing to the traditional method of design. The output voltage and frequency are tested, as shown in Figure 23 as well as the relationship between the output waves and the generated PWM signals which are generated

In Figure 23, comparing the two waveforms, it can be seen that the result obtained by the developed model is in a good agreement with the actual result in both frequency and voltage amplitude. It is apparent that the narrow pulse is generated when the modulating

(a) Actual

(b) Simulation

The inverter power supply output distortion or the output voltage drop is considered a very important issue in the design of the inverter power supply. There are many regulations regarding the allowable voltage drop in the inverter power supply. For example, based on the standard IEC686, the allowed voltage drop is no more than 5% voltage against single

by the microprocessor and controlled by the embedded software.

signal is at its maximum or minimum values.

Fig. 23. Sin wave output of inverter power supply:

**Response with linear load** 

parameter. Various techniques are used to compensate the effect of the voltage drop in the inverter power supply design. One of the main techniques is to apply the control system. The main duty of the inverter control system is to regulate the output voltage against the entire possible disturbance and the load variations. As mentioned before, the two layer control algorithm which consists of the feedback PI controller plus the feed-forward controller is proposed to control the inverter power supply. The validity and usefulness of this controlling algorithm are tested in the existence of linear load. Figures 24 and 25 show the output of the inverter power supply with no load and after connecting the load resistance Rl = 60Ω respectively. From Figure 25, we can see the voltage reduction at the moment when the resistance is connected but due to the control algorithm, the voltage can return to its value within a very short time. We can conclude that the proposed control algorithm is able to modify the distortion that occurred due to the load in a very short time. So, using the control algorithm can improve the inverter power supply's performances.

Fig. 24. Inverter power supply output with no load

Fig. 25. Inverter power supply output with no load in the MILS

Potential of Grid Technology for Embedded Systems and Applications 353

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Comparing the result with no load and the result with load, it seems that the shapes of the wave forms are almost identical except in the moment that the load resistances are connected. The voltage decreased by about 2% of no load voltage for a very short time of approximately 100 msec, and then it returned to its normal value. So, we can conclude that the proposed controlling algorithm is working well, and it can maintain the disturbance occurred due to the load connection.
