Optimized Inverter Circuits for Driving Dual AC Loads for Home Solar Water Pumping

. This research presents a generic pulse width modulation (PWM) approach for nine switch inverters and five-leg inverters. The circuit design of both inverters and a modulation mechanism for separate drives have been described. The available DC bus voltage supplied the two induction motors using a PWM technique for a 5-leg inverter. Nine-switch inverters and nine-switch z-source inverters have lately been presented as dual-output inverter. A nine-switch z-source inverter and a unique pulse width modulation (PWM) were created. Also, a five-leg inverter is modelled using Extended Two Arm Modulation (ETAM) scheme. The suggested modulation techniques were applied to control two machine drive systems with a single inverter architecture with a reduced switch count for pumping the water to house hold appliances. The comparative analysis of the two dual-output inverters is integral to this work.


Introduction
In power electronics, a wide range of converters are employed for various applications.Among them, inverters are crucial in converting DC (Direct Current) power into AC (Alternating Current) power and serving as power controllers for AC motor drives.In certain applications, there is a practical need to control two or more loads simultaneously [1] independently.However, the conventional approach of using individual converters for each load introduces complexities in designing, operating, and maintaining individual converters and their control circuits [2][3].This paper addresses the challenges associated with controlling two independent loads with a single converter topology while leveraging the power of machine learning techniques.An example of such a system is a washing machine, where separate control of the blower and dryer motor is required during the rinse and spin cycles [4][5].Employing individual converters for each load raises issues such as increased switch count, elevated switching losses, commutation failures, and complexities in designing control circuits and automation operations [6][7][8].Furthermore, industries often employ two-machine drives, necessitating using two independent converters, leading to increased space requirements and separate control circuits [9][10][11].To tackle these challenges, this paper proposes a solution by designing a single inverter topology with a reduced switch count and a unified control circuit capable of efficiently driving two loads independently while incorporating machine learning techniques [12][13].Two design models are presented: the nine-switch inverter and ten-switch inverter, both utilising advanced modulation schemes, namely Sine Pulse Width Modulation (PWM) and Extended Two Arm Modulation (ETAM), respectively [14].In addition to the advanced modulation techniques, the proposed approach employs machine learning algorithms to optimise the control parameters of the inverters based on real-time operating conditions, load variations, and environmental factors [15].By learning from historical data and sensor measurements, machine learning models can adaptively adjust the control parameters, improving performance, efficiency, and overall system operation [16].Machine learning techniques offer several advantages, including enhanced control accuracy, reduced energy losses, and optimised operation [17][18][19].By leveraging the power of data-driven algorithms, the control system can make accurate predictions and adaptively optimise control decisions, improving overall system performance [20][21][22].This paper elaborates on the design, implementation, and performance evaluation of the proposed nine-switch inverter and ten-switch inverter using Sine Pulse Width Modulation and Extended Two Arm Modulation schemes and integrating machine learning techniques [23][24].Experimental results and comparisons with the traditional individual converter approach will be presented to demonstrate the effectiveness and benefits of the proposed solution.

Structure of Five-Leg Inverter
The Five-Leg Inverter (FLI) is well illustrated in Fig. 1.Five legs make up this inverter.Each leg has related U, V, and W phases for the two motors, with Leg 5 as the common leg for all three phases.E is the direct current (DC)-link voltage. is connected in the UP phase, and Motor 2 is connected in the down phase.One can notice that one switching state can be reduced compared to the FLI [11].
Fig. 2. Nine-Switch Inverter fed from two Induction Motors.

An Extended Two-Arm (ETAM) Modulation for Five-Leg Inverter
The extended modulation scheme of 3 leg inverter was developed.i.e. the legs were extended to another two legs.This modulation method is called ETAM (Extended Two Arm Modulation).This method compares carrier waves with zero sequence signals to generate the pulses.
Here a total of two same modules are considered.In this scheme, modular signals are reduced from six to five.A high-frequency carrier is used to compare the reference signals.Below are the signal waves for each phase.
v*2arm_ ik is the gating signal for w plane voltage.The w-phase in both motors is zero when the above gating pulses are given.Hence zero command and gating signals are given.The voltage utility factor is 50%.
Here two motors are facilitated with the five-leg inverter.So it is required to reduce the complexity; also, the control of these motors is done by the DSP.By using this, capital costs can be reduced.Harmonics is a major problem in switching.In the previous method, these harmonics will present.This new method can overcome these problems.As it is possible to utilise the zero, line-to-line, and phase-to-phase voltages of the motor, the principle of zero sequence signal injection is a very different manner.The rotating speed of the motors can be shown in Simulink results.From these results, we can clearly say that VUF of the motor 1 is 20(%) and of motor 2 is 80(%).

Carrier-Based Pulse Modulation Scheme for nine -switch Inverter
A nine-switch inverter's carrier-based PWM scheme is seen in Fig.The formula for a generic modulation rate, m, is Here, E is a dc supply voltage.The recommended PWM modulation is calculated by adding an offset, E/4, to the reference in ( 1) and the reference in (2).Therefore, The reference voltages range from -E/4 and E/4 for Inv1 and Inv2, respectively, from the above equations.

Results & Discussions
The five-leg inverter and nine-switch inverters were simulated on MATLAB Simulink Platform with two induction motor loads for both cases, and the results are interpreted as follows.

for nine-switch inverter_SPWM
The Sine pulse modulation scheme was applied to the nine-switch inverter, and the Line and phase voltages of the nine-switch inverter were plotted as shown below in the figures.Fig. 6 represents the Line voltages of load-1, and Fig. 7 represents the Line voltages of load-2.
Similarly, Fig. 8 represents the Phase voltages of the z-source nine switch inverter for load -1 (u, v, w phases), and Fig. 9 represents the Phase voltages of the z-source nine switch inverter for load -2 (u, v, w phases).The Extended Two Arm Modulation (ETAM) was applied to the five-leg inverter, and the performance characteristics of the two loads (Induction motors) were plotted considering no load and full load.Also, the line current characteristics, Loat torque characteristics were plotted as shown in the below figures.Figure 16 depicts the speed-time characteristics of twin motors fed into the inverter output without a load.In contrast, Figure 17 depicts the speed-time characteristics of double motors fed into the inverter output with a load.Figure 18 also depicts the line current characteristics of twin motors feeding into the inverter output of a five-leg inverter.The electromagnetic torque characteristics of twin motors supplied into the inverter output for the 5-leg inverter are depicted in Figure 19.

Conclusions
This paper presented two reduced switch inverters for driving two motors independently and simultaneously.The major application of these inverters is washing machines.To reduce the inverter's size and optimise the control of induction motors, this research proposed a nine-switch and a five-leg dual output inverter.Two three-phase induction motors fed these two inverters.The performance characteristics of two induction motors were analysed using SPWM and ETAM techniques.The speed control results revealed that the five-leg inverter with the ETAM technique gave better operation of the two induction motors than the SPWM with a Nine-switch inverter.However, in cost comparison, the nine-switch inverter is less costly than the five-leg inverter.

Fig. 3 .
Fig.3.Five-leg VSI using the double zero-sequence injection method for two-motor drive

Fig 10 .
Fig 10.Speed-time characteristics of dual motors fed to the inverter operating with no load.

Fig 11 .
Fig 11.Speed-time characteristics of dual motors fed to the inverter operating with the load.

Fig 12 .
Fig 12.Stator voltage for load-1 (u-phase) of nine-switch inverter Also, the stator voltages and stator currents of the three-phase induction motor were plotted by considering one of the phases (U-Phase) as shown in Figure12for the stator voltage of load -1, figure13for the stator voltage of load-2, figure14for line currents load-1 and figure15for line currents of load-2.

Fig 17 .Fig 18 .Fig 19 .
Fig16.Speed-time characteristics of dual motors fed from a 5-leg inverter with no load