Embedded Systems and Design & Development - Feb 5, 2026 | Afternoon | VisionAstraa EV Academy

Electric Vehicle Technology: Understanding Motors

Introduction to Electric Vehicle Motors

• The discussion begins with an overview of electric vehicle technology, specifically focusing on the importance of understanding motors after previously covering battery technology.

• The speaker prompts the audience about their preference for continuing with motors or revisiting battery applications, ultimately deciding to proceed with motors.

Types of Electric Vehicle Motors

• Three basic types of motors used in electric vehicles are introduced: mid-drive motor, hub drive motor, and shaft drive motor.

Mid Drive Motor

• In a mid-drive motor, the center shaft rotates while the outer body remains stationary. This design is common in various applications including bicycles and some electric vehicles.

Hub Drive Motor

• A hub drive motor features a stationary middle part (shaft), with the external part rotating. This type is often integrated into the wheel itself for direct propulsion.

Shaft Drive Motor

• The shaft drive connects directly to the vehicle's rear wheel via a mechanical shaft. Unlike mid-drive systems that use chains or belts, this system offers a more straightforward connection.

Functionality of Motors

• Motors can function as both generators and motors; when powered electrically, they act as motors converting electrical energy into mechanical energy. Conversely, when mechanically rotated, they generate electrical output.

Comparison and Internal Structure of Motors

• A visual representation shows differences between hub and mid-drive motors regarding their internal structures and operational mechanics.

Key Components

• The external rotor in hub motors is mounted directly on the winding shaft while mid-drive motors have fixtures that allow rotation around a stationary body.

Conclusion on Motor Types

• The session concludes by encouraging participants to list different types of AC and DC motors for further exploration in subsequent discussions.

Understanding Electric Vehicle Technology

The Interdisciplinary Nature of Electric Vehicles

• The learning process involves switching from slides to a camera for better understanding of concepts in electric vehicle technology.

• Electric vehicle technology integrates multiple fields: mechanical engineering, electrical engineering, electronics, and computer science.

• A foundational knowledge across all these disciplines is essential for designing or developing specific components of an electric vehicle.

• The focus will be on providing an overview rather than deep dives into each component's complexities.

Introduction to Motor Types

• The session begins with an overview of motor operation modes, categorizing them into AC motors and DC motors.

• Discussion on battery packs highlights that they operate on DC power, which influences the choice of motors used in electric vehicles.

Types of Motors in Electric Vehicles

• In AC motors, the types discussed include induction motors and synchronous motors; while in DC motors, series and shunt (parallel) motors are mentioned.

• Focus shifts to Brushless Direct Current (BLDC) motors as the primary type utilized in electric vehicles.

Exploring BLDC Motors

• An explanation of BLDC motor advantages over brushed DC motors will be provided later in the discussion.

• Key components of a BLDC motor include permanent magnets and windings; these parts are crucial for its operation.

Structure and Functionality of BLDC Motors

• Description includes how permanent magnets are arranged alternately around the external rim to create magnetic fields necessary for operation.

• The construction details reveal that energizing the motor produces artificial magnetism essential for functionality.

Motor Types Comparison

• Two types of BLDC configurations are introduced: hub drive motor and mid-drive motor. Each has distinct operational characteristics relevant to vehicle design.

Practical Application in Offline Classes

• Future offline classes will provide hands-on experience where students can design their own battery packs and integrate them with motors to run vehicles.

Understanding the Basics of Motor Construction and Operation

Introduction to Motor Components

• The session will cover the construction and operation of a motor, focusing on the rotor with permanent magnets and the stator's magnetic components.

Magnet Interaction Principles

• An example is introduced using two magnets: one north pole and another north pole. When similar polarities are brought together, they repel each other.

• Conversely, when opposite polarities (north and south) are brought together, they attract each other. This fundamental principle of attraction and repulsion is crucial for understanding motor function.

• The basic working principle of motors relies on this interaction between different polarities—attraction occurs with opposites while repulsion occurs with like poles.

Application in Brushless DC Motors (BLC)

• The BLC motor operates based on the same principles of attraction and repulsion between magnets.

• A conductor wound into coils acts as an artificial magnet when powered; its polarity depends on current direction.

Creating Artificial Magnetism

• By controlling current direction through a conductor, artificial magnetism can be generated: positive current creates a north pole while negative current creates a south pole.

• This concept aligns with Faraday's law, which relates to electromagnetism principles known by electrical students.

Motor Functionality Explained

• In practical application within the motor design, multiple slots will be used to implement this system effectively.

• When power is supplied correctly (positive to one side), it generates specific magnetic polarities that influence movement within the motor structure.

Movement Dynamics in Motors

• As magnetic forces interact (e.g., north against north), parts of the motor will attempt to move due to repulsive forces acting upon them.

• To achieve effective motion, multiple magnets are utilized within the rim structure; their arrangement influences overall functionality.

Inducing Magnetic Polarity

• The introduction of additional magnets allows for more complex interactions; for instance, inducing opposite polarities can lead to attractive forces that facilitate rotation.

Understanding Magnetic Interactions in Motors

Initial Magnetic Configuration

• The discussion begins with the concept of magnetic poles, specifically focusing on the interaction between north poles. The idea is that when two north poles are brought close together, they will repel each other.

• A visual representation is introduced to illustrate how one north pole moves forward due to this repulsion, setting the stage for further exploration of magnetic interactions.

Transitioning Between Conditions

• As the magnets move, a south pole comes into play, which attracts the north pole. This attraction leads to a shift in position as magnets interact differently based on their polarities.

• The speaker labels the magnets (N1 and N2 for north poles; S1 and S2 for south poles), emphasizing how their positions change during rotation.

Locking Mechanism of Poles

• At this point, both a north and south pole are present, leading to an attraction that locks them in place. This locking mechanism prevents movement due to magnetic forces.

• The transition from repulsion (north-north interaction) to attraction (north-south interaction) highlights how polarity changes affect magnet behavior.

Challenges in Motor Rotation

• To achieve continuous motor rotation despite magnetic locking, polarity must be reversed. This reversal is crucial for maintaining motion within the motor system.

• The speaker discusses changing polarity by reversing current flow through coils while keeping windings consistent.

Reversal of Polarity Effects

• After reversing polarity, both ends act as south poles initially; thus, repulsion occurs again. However, this creates another challenge where opposite polarities may lock up once more.

• Further adjustments are made by changing polarities again to ensure that opposing forces do not hinder movement.

Conclusion: Understanding Motor Functionality

• Ultimately, these discussions lead back to understanding basic motor functionality—how alternating current can facilitate continuous rotation through controlled magnetic interactions.

• Emphasis is placed on learning these principles as foundational knowledge necessary for designing controllers that manage motor operations effectively.

Understanding the Basics of Motor Operation and Hall Sensors

Motor Rotation and Polarity Change

• The motor operates on the principles of attraction and repulsion, allowing it to rotate when polarity is changed.

• Emphasis on understanding how to change polarity using power electronics components, which are crucial for motor operation.

• Discussion about artificial windings in motors, highlighting the copper winding process used in construction.

• Explanation of how supplying positive or negative power creates north or south pole magnets, respectively.

• Challenges in identifying magnet polarities visually; random placement makes it difficult to discern north from south poles.

Identifying Magnet Polarity

• Inquiry into methods for recognizing magnet polarities without prior knowledge; emphasizes the need for identification tools.

• Introduction to Hall sensors as a solution for detecting magnetic polarity effectively.

Introduction to Hall Sensors

• Overview of Hall sensors compared to other sensors like LDR (Light Dependent Resistor), explaining their operational principles.

• Description of Hall effect sensors functioning similarly to BJT transistors with three main terminals that detect magnetic fields.

• When a north pole magnet is placed near a Hall sensor, it generates an output signal indicating its presence; no signal is produced by a south pole magnet.

Digital Signal Output from Hall Sensors

• Explanation of digital signals where 'zero' indicates an off condition and 'one' indicates an on condition; relates this concept back to electrical engineering fundamentals.

• Creation of a truth table based on sensor outputs: North pole results in 'one' (on), while South pole results in 'zero' (off).

Application of Hall Sensors in Motor Control

• Discussion on how the outputs from Hall sensors can be utilized in designing controllers for motors, enhancing their functionality based on detected magnetic fields.

• Reinforcement of understanding regarding how Hall sensors work and their significance in sensing magnet polarity effectively.

Understanding Motor Control and Hall Sensor Functionality

Initial Conditions of the Motor System

• The output of the motor system is determined by the hall sensor detecting a north pole, resulting in a high signal (1) when positioned correctly.

• Stator polarity can be controlled by the supply voltage; positive supply creates a north pole while negative supply results in a south pole. This control is crucial for motor operation.

Signal Interpretation and Polarity Changes

• In the first condition, the hall sensor indicates a high signal (1), which informs decisions about power supply direction for optimal motor function.

• When the hall sensor detects a low signal (0) in the second condition, it prompts changes to the power supply to ensure proper magnetic interaction between rotor and stator.

Magnetic Interaction Dynamics

• The relationship between similar and different polarities is fundamental: like poles repel while opposite poles attract, guiding how current flow influences magnetism within the motor system.

• Understanding this dynamic allows for effective control over motor operations based on real-time feedback from hall sensors regarding polarity changes.

Integration of Hall Sensors with Motor Windings

• Each winding in the motor has an associated hall sensor that provides critical feedback on position and polarity, essential for automated control systems. There are three main windings identified as outputs from the motor.

• The wiring configuration includes three major power outputs along with five lines dedicated to hall sensors, ensuring comprehensive monitoring and control capabilities within the system.

Practical Application of Concepts

• A visual representation of actual windings demonstrates how theoretical concepts translate into physical components within motors, emphasizing practical understanding alongside theoretical knowledge. This includes color-coded wiring for clarity during assembly or troubleshooting processes.

Understanding Motor Control and Hall Sensors

Overview of YGB Sequence and Hall Sensors

• The sequence of windings in the motor is referred to as YGB, which stands for Yellow, Green, and Blue.

• The hall sensor lines are identified with positive and negative connections; one line serves as positive while the other is negative.

• Each winding (yellow, blue, green) has its dedicated hall sensor to monitor their respective outputs.

Practical Application of Hall Sensors

• The practical setup includes three wires from the hall sensor: one for positive, one for negative, and a middle sensing line.

• In offline sessions, hands-on experience will be provided on troubleshooting and placement of hall sensors within motors.

Introduction to Motor Controllers

• Transitioning from understanding motor workings to exploring how polarity changes occur through controllers.

• The controller is also known as MCU (Motor Control Unit), which plays a crucial role in managing motor functions.

Functionality of MOSFET in Controllers

• The MCU consists of multiple MOSFET switches that control power flow within the system.

• A MOSFET has three terminals: Drain, Source, and Gate (DSG), essential for switching operations in power electronics.

Circuit Design Using MOSFET

• A simple circuit can be built using two MOSFETs where the gate acts as a trigger to switch power continuity between drain and source.

• When applying positive voltage at one terminal and negative at another across a winding, it generates magnetic poles (north/south).

Polarity Management via Microcontrollers

• By changing input polarities through MOSFET configurations based on gate signals from microcontrollers, effective control over magnetism is achieved.

• When both MOSFET gates are activated simultaneously with appropriate battery connections, they produce specific magnetic polarities necessary for motor operation.

Understanding MOSFET Control for Magnetic Polarity

Introduction to MOSFET Configuration

• The microcontroller sends a gate signal to activate two MOSFETs, inducing a north pole magnet.

• A second pair of MOSFETs is introduced with similar configurations for positive and negative terminals.

Controlling Magnetic Polarity

• To achieve north polarity, MOSFET 1 (M1) and MOSFET 2 (M2) are activated while M3 and M4 remain off.

• When M1 and M2 are on, the circuit produces a positive output leading to a negative supply, creating north polarity.

Switching to South Polarity

• To switch to south polarity, M3 is turned on while M1 and M2 are turned off.

• This configuration ensures that only the necessary MOSFETs are active without interference from others.

Detailed Operation of the Circuit

• The first condition establishes north pole polarity; switching conditions will reverse this setup for south pole generation.

• For south polarity, M1 remains off while both M3 and M4 are activated, reversing the magnetic field direction.

Summary of Component Usage

• Four MOSFETs are required to change the polarity of one winding effectively.

• With three windings in total, twelve MOSFET connections would be needed across all windings for complete control.

Role of Hall Sensors and Microcontroller

• Each winding requires specific connections managed by hall sensors; four sensors may be needed per winding based on individual requirements.

• The microcontroller processes signals from hall sensors to manage the operation of the connected MOSFET circuits effectively.

Conclusion: Understanding Input Requirements

• Each input MOSFET needs gate input signals which will be discussed further in upcoming sessions.

• The microcontroller's role is crucial as it interprets sensor outputs to determine appropriate actions within the system.

How Does a Microcontroller Operate with Hall Sensors and MOSFETs?

Overview of Microcontroller Functionality

• The microcontroller operates based on input from hall sensors, controlling the state of MOSFETs. When the hall sensor input is high, it activates MOSFET 3 and 4 while deactivating MOSFET 1.

Inputs and Outputs of the Microcontroller

• A programmable microcontroller receives various inputs including a 5V power supply and ground connections. It manages multiple signals for operation.

Gate Signals and Sensor Data

• The system generates a total of 12 gate signals for controlling MOSFETs, alongside data from three hall sensors that provide necessary feedback for operation.

Control Logic Based on Hall Sensor Input

• When hall sensor one outputs a high signal (1), it triggers MOSFET 3 and 4 to turn on while turning off MOSFET 1 and 2, effectively changing polarity which influences motor rotation.

Working Principles of BLC Motor System

• The entire system relies on three main components: hall sensors, the microcontroller, and MOSFETs. A minimum of twelve MOSFETs are required to control three windings in the motor setup.

Learning Approaches for Students

• Students attending offline sessions will engage in hands-on activities related to microcontroller programming and circuit integration, while online learners will focus on theoretical aspects such as PCB design.

Understanding Motor Ratings

• The wattage rating of motors is influenced by the number of turns in their windings; more turns result in different calculations regarding power consumption.

Controller Design Overview

• An illustration is provided showing how the controller integrates positive/negative battery inputs with outputs directed towards three windings (yellow, green, blue).

Final Integration Details

• The controller's layout includes connections for each winding output along with integrated MOSFET configurations tailored to manage these outputs effectively.

Overview of Today's Session

Key Learnings from the Session

• The session covered the basic workings of a motor, including its components such as hall sensors, windings, permanent magnets, and polarity.

• Discussion on the outputs of the motor revealed three power outcomes and highlighted the role of the Motor Control Unit (MCU).

• Clarification was made that MCU stands for Motor Control Unit, not Microcontroller Unit; emphasis on understanding BLC motor functionality.

Types of Motors Discussed

• Two types of motors were introduced: hub drive motors and mid-drive motors. Participants were encouraged to note these distinctions in their diaries.

• The importance of understanding various motor types and their operational principles was reiterated, particularly focusing on hall effect sensors.

Upcoming Sessions and Topics

• Plans for future sessions include a detailed exploration of battery placement and assembly processes.

• A live demonstration is proposed for an upcoming session to clarify battery manufacturing concepts, addressing previous confusion during theoretical discussions.