Electrical Engineering Project - Essay Example

? Electrical engineering project Project Objective To design a MOSFET based H-Bridge circuit that can be used in controlling the direction of a DC motor. Background It has been acknowledged that in most cases, the micro controller of a rower or a robot is not in a position to offer the current required to power motors. In the current world, having motors capable of producing high power output is a necessity. This is because such motors are driven in extreme conditions requiring high speed, and abrupt changes in direction as well as being subjected to heavy loads. It is not easy to find motors for use in such conditions under a tight budget. It is also important to note that some motors produce immense output power, but cannot be efficient enough. It is under such conditions that people make use of H Bridge in the efficient control of the Motors’ direction. Project Fundamentals An H-bridge circuit refers to a power circuit that is electric, and used in the control of electric motors like DC motors used in automotive applications. The H-bridge functions in controlling the direction and speed of the motor by allowing a limited amount of current to flow in the motor through the right direction (Barrett, 2012). It is made up of four MOSFETs, which are under the control of control signals of the (PWM) Pulse Width Modulation. The original design of the DC motor control incorporates Multisim LabVIEW co-simulation that permits the performance of the entire system to be authenticated on the desktop. The motor has such parameters as inductance, the load weight, and armature resistance for accurate verification of the results of the performance. The use of a multisim-labVIEW co-simulation ensures that one shall not have to digital and analog systems separately. During the implementation stage of the model, the circuitry of the analog can be transferred for photocopying to the Ultiboard. Such a transition between the Ultiboard and Multisim makes sure that there is a precise convey of simulated designs. The graphical code of control is moved to a Single Board Rio 9695 target. This is usually an acquisition device and an embedded control that puts together a FPGA that is user-reconfigurable, a real time processor, and input or output of printed circuit board. The four MOSFETs needed in designing a H-bridge can be demonstrated with the diagram below. Two of the MOSEFETs should be of P channel (IRF9540N), while the other two should be of N channel (IRF540N). They should be designed in such a way that the motor’s rotation is controlled through an on-off-on switch. The motor’s closed-loop control starts through inputs that are user-defined such as the necessary step size and speed. This message is resent to the Multisim design through the co-simulation terminals. Negotiations between labVIEW and Muiltisim occur as a guarantee in conversation and accuracy for both sides. In case of abrupt drops or peaks in Multisim, negotiation in time-step allows Multisim to alter the available time-step to view the drops and peaks. A point by point model between digital systems and analog circuits results to an advanced system both in accuracy and behavior. Once the verification of the system design has been made with Multisim and labVIEW co-simulation, the complete circuit can be moved to Ultiboard for routing and layout. List of Components The list of components used in the circuit includes: MOSFET P Channel (IRF9540N) – 2 MOSFET N Channel (IRF540N) – 2 Motor – DC 6 volts Battery – 9 volts Switch – 1 Connecting Wires and Strip Board Controlling the Motor The control of the motor is done through the two ways switch connected to Q1 and Q3 of the circuit. If a signal is sent to Q1the motor is stimulated to move in a forward direction, while on the other hand, if a signal is sent to q3 the motor is stimulated run in a reverse direction. It is never possible to sent signals to both Q1 and Q3at the same time because of the use of on off on switch. This can be summarized using the following table: Q1 Q3 Stop 0 0 Forward 1 0 Reverse 0 1 Not Applicable 1 1 Challenges This project had a number of challenges. One of these challenges was the acquisition of the components required in building the entire circuit. This was majorly because some of the components required were unavailable in most shops, and those that were available could not match the required properties. The search for the appropriate components therefore required a lot of time and money. A further challenge was that at times, valuable money and time was spent in the construction of a circuit that ended up failing in function. For instance, the initial circuit that was built had problems that could not be solved. These problems resulted to a decision to construct a simpler circuit. The greatest challenge was time management, although it could have been improved. A lot of time was spent in the search for the appropriate material; hence, limited time was available for the construction of the circuit as well as the solving of problems within the circuit. Final design of the circuit over the strip board The final design of the circuit was as follows: Conclusion One of the most noteworthy attributes of the MOSFET circuits is that they can hold an intrinsic diode in between their source and drain. The diode can act as a catch diode in H-bridge configuration (Barrett, 2012). It is therefore, possible to use such built-in diodes of circuits instead of external ones, if such diodes meet the requirements of the design. It is also possible to build a transistor based H-bridge using a microcontroller that has the ability to control a more complete circuit. It is also possible, on the other hand, to build a manual motor direction switch if the motor is to be manually controlled. There are more strong solutions available when one is in need of a circuit that can drive motors electronically. Work cited Barrett, S. Arduino. (2012). Microcontroller: Processing for Everyone! Second Edition Synthesis Lectures on Digital Circuits and Systems. San Rafeal: Morgan & Claypool Publishers. Read More