EV Drivetrain
Aim :
- EV Drivetrain
Objective :
- Which types of power converter circuits are employed in electric and hybrid electric vehicle?
- An Electric Vehicle's powertrain with 72V battery pack in shown in the diagram below. The duty ratio for acceleration operation is 'd1' and for the braking operation the duty ratio is 'd2'.
The other parameters of the electric vehicle is given below,
Motor and Controller Parameters:
Rated Armature voltage= 72 V
Rated armature current= 400 A
Ra= 0.5Ω, KΦ= 0.7 Volt second
Chopper Switching frequency= 400 Hz
The vehicle speed-torque characteristics are given by the below equation
What is EV steady state speed if duty cycle is 70%? -
Develop a mathematical model of a DC Motor for the below equation using Simulink.
ω">ωω=(vKϕ)−(RaKϕ.2)⋅T= V/Kϕ">ϕω -Ra/Kϕ">ϕKϕ^2 .T
- Explain in brief about author’s perspective in given blog
# First objective :
types of power converter circuits are employed in electric and hybrid electric vehicle
what are the power converter circuits
A power converter is an electrical circuit that changes the electric energy from one form into the desired form optimized for the specific load. A converter may do one or more functions and give an output that differs from the input.
A device that increases or decreases the voltage (AC or DC) of a power source depending on application. A converter that increases voltage is called a step-up converter and a converter that decreases voltage is called a step-down converter. In EVs/HEVs step-up and step-down converters are combined into one unit. An application of a step-up converter is converting EV/HEV battery voltage (typically 180-300 volts) to about 650 volts to power the traction motor. An advantage of using a converter to increase voltage from the battery is a smaller and less expensive battery may be used while still utilizing an efficient high voltage motor. An application of a step down inverter would be decreasing the high voltage direct current (DC 180-300 volts) from the HEV/EV battery to low voltage (12-14 volts) DC that can be used to charge the 12 volt auxiliary battery and operate light load devices such as lighting, radio, and windows.
- The Power Electronic Converter can be classified into six types:
- Diode Rectifier.
- AC to DC Converter (Controlled Rectifier)
- DC to DC Converter (DC Chopper)
- AC to AC Converter (AC voltage regulator)
- DC to AC Converter (Inverter)
- Static Switches.
In EVs, the Fuel Cell (FC) stack, battery bank, and Super- capacitors (SCs) bank are usually used as clean energy sources. . In order to design highly efficient converters for the EV's power system, advanced DC/DC , AC/DC and DC/AC converters are required to adapt the output voltage and current levels with high power quality.
DC to DC Converter (DC Chopper) :-
Electric Vehicles (EVs), Hybrid Electric Vehicles (HEVs) and Fuel Cell Electric Vehicles (FCEVs) have been typically proposed to replace conventional vehicles in the near future. ... DC-DC converters can be used to interface the elements in the electric power train by boosting or chopping the voltage levels.
DC-to-DC converters are used to reduce High voltage DC input to low voltage DC output for some specific appliances. They are also used to isolate some highly sensitive components in a circuit from other components of the circuit to avoid any kind of damage.
Electric vehicles (EV) use two different power systems; a high-voltage battery (200 to 450 VDC) for traction and a low-voltage (12 V) one for supplying all the electric appliances in the vehicle. Traditionally the low-voltage battery was charged from the alternator, but in today's vehicles it gets its power from the high-voltage battery pack. However, in specific electric car architectures, this low voltage battery should be ready to help recharge the high-voltage battery pack in order to provide energy for cranking the car. This means that the on-board DC-DC converter must be bi-directional and very efficient as well as highly reliable in order to run the complex control algorithms needed to ensure an energy-efficient solution.
Introduction to Power Electronics Converter:
Power electronic technology deals with processing and controlling the flow of electrical energy in order to supply voltages and currents in a form that optimally suited for end user’s requirements.
A power electronic converter uses power electronic components such as SCRs, TRIACs, IGBTs, etc. to control and convert the electric power. The main aim of the converter is to produce conditioning power with respect to a certain application.
The block diagram of a power electronic converter is shown in figure above. It consist of an electrical energy source, power electronic circuit, a control circuit and an electric load. This converter changes one form of electrical energy to other form of electrical energy.
The power electronic circuit consists of both power part and control part. Power part transfers the energy from source to load and it consists of power electronic switches (SCR or TRIAC), transformers, electric choke, capacitors, fuses and sometimes resistors.
The control circuit or block regulates the elements in the power part of the converter. This block is built with a complex low power electronic circuit that consists of either analog or digital circuit assembly.
Power electronic converters perform various basic power conversion functions. This converter is a single power conversion stage that can perform any of the functions in AC and DC power conversion systems.
Depending on the type of function performed, power electronic converters are categorized into following types.
- AC to DC = Rectifier: It converts AC to unipolar (DC) current
- DC to AC = Inverter: It converts DC to AC of desired frequency and voltage
- DC to DC = Chopper: It converts constant to variable DC or variable DC to constant DC
- AC to AC = Cycloconverter, Matrix converter: It converts AC of desired frequency and/or desired voltage magnitude from a line AC supply.
These types of power electronic converters may be found in a wide variety of applications but among them only three types of power converter circuits are employed in electric and hybrid electric vehicle. The following power converter circuits are discussed below,
- AC to DC Convertes or Rectifier:
An AC to DC converter is also called a rectifier, which converts AC supply from main lines to DC supply for the load. The block diagram of an AC to DC converter is shown in figure below.
The essential components in this rectifier include transformer, switching unit, filter and a control block.
Here, the transformer adjusts the primary AC source supply to the input of rectifier stage. Usually it is a step-down transformer that reduces the supply voltage to a circuit operating range.
The rectifier converts the low voltage AC supply into DC supply.
It comprises diode and/or thyristors based on type of rectifier. The output of the rectifier is of pulsed DC and hence it is filtered using filter circuit, which is usually made with a capacitor or a choke.
The control block controls the firing angle of thyristors in case of phase controlled rectifiers. Since the diode is not a controllable device, control block is not needed in case of diode rectifiers.
Rectifiers are majorly classified into two types
- Uncontrolled diode rectifiers
- Controlled rectifiers
Uncontrolled Diode Rectifiers
This type of rectifier converts AC voltage from mains into a fixed DC voltage.
Since the diodes are uncontrollable components (which do not require any triggering), these converters are called as uncontrolled converters as they produce a fixed voltage. The input voltage can be either single phase or three-phase.
The diode rectifiers are classified into following types.
- Single Phase half-wave rectifier:-
The Single Phase half-wave rectifier is a type of rectifier that rectifies only half cycle of the waveform. This article describes the half wave rectifier circuit working. The half rectifier consist a step down transformer, a diode connected to the transformer and a load resistance connected to the cathode end of the diode. The circuit diagram of half wave transformer is shown below:
The main supply voltage is given to the transformer which will increase or decrease the voltage and give to the diode. In most of the cases we will decrease the supply voltage by using the step down transformer here also the output of the step down transformer will be in AC. This decreased AC voltage is given to the diode which is connected serial to the secondary winding of the transformer, diode is electronic component which will allow only the forward bias current and will not allow the reverse bias current. From the diode we will get the pulsating DC and give to the load resistance RL.
- Single Phase center-tapped full-wave rectifier:-
Center tap is the contact made at the middle of the winding of the transformer.
Center Tapped Full Wave Rectifier Circuit Diagram In the center tapped full wave rectifier two diodes were used. These are connected to the center tapped secondary winding of the transformer. Above circuit diagram shows the center tapped full wave rectifier. It has two diodes. The positive terminal of two diodes is connected to the two ends of the transformer. Center tap divides the total secondary voltage into equal parts.
- Single Phase full-wave bridge rectifier:-
In Single Phase full-wave bridge rectifier four diodes are used. These are connected as shown in the circuit diagram. The four diodes are connected in the form of a bridge to the transformer and the load as shown.
Bridge Rectifier Circuit Diagram - Three-Phase Half-wave diode rectifier:-
It employs three diodes and its anode terminals are connected to three phase source via transformer as shown in figure. The load is connected between the common cathode point and neutral terminal of star connected source.
When R-phase is at its peak value, maximum conduction occurs through diode D1 as it is forward biased and no conduction takes place through it during negative alteration of phase R. During Y-phase and B-phase maximum values, other two diodes conduct in a similar manner.
The main disadvantage of this rectifier is that the secondary winding consists of DC component of current which can cause the transformer core to go under saturation problem.
Therefore, it is not advisable to use three-phase half-wave rectifier for large power applications.
- Three-Phase full-wave diode rectifier:-
This type of rectifiers is suitable for high power applications, typically the power output higher than 15KW. The circuit of full-wave diode bridge rectifier is shown in figure below.
It requires six diodes for the operation of the circuit. This type of circuit doesn’t need any neutral connection from three phase source therefore, a star as well as delta-connected sources can be used.
Here the output current flows through one diode of the upper group and one diode of lower group of diodes. If anode of a diode is at high potential, this upper group diode will conduct while other two diodes are reversed biased.
Similarly, the diode having the cathode at lower potential will conduct while other two diodes are off. The diode pair’s conduction for above circuit is given as D6 D1, D1 D2, D2 D3, D3 D4, D4 D5 and D6 D1.
Since, one diode from upper group and one diode from lower group are always conducting; negative members of three- phase voltages are rectified, so the output voltage consists of six segments of line voltage during one cycle.
For this reason, three phase bridge rectifiers are called as six pulse rectifiers.
These are efficient rectifier as compared to half-wave converters. Due to six pulse output, ripple content in the output is very low, typically about 4.5%.
This avoids the additional filter circuit in many high power applications. Even it a filter is required, a small sized filter is enough because of increase in ripple frequency to six times the input frequency.
Phase Controlled rectifiers:
These are similar to the uncontrolled rectifiers but the only difference is that the uncontrolled diodes are replaced by controlled thyristor family of devices such as SCRs.
These are also called as phase controlled rectifiers. Unlike diodes, thyristors can be controlled by triggering them at desired instants in order to vary the output voltage.
The block diagram of a controlled rectifier is shown in the above figure that transfers the DC power to the load in a control manner by varying triggering angle of thyristors (by the control circuit) using different technologies such as a microprocessor or microcontroller based techniques.
The start of thyristor conduction varies the average value of output voltage of the converter. Similar to the uncontrolled rectifier types, these thyristor based converters are also classified into following types.
Single Phase half-wave rectifiers:
In this a single thyristor or SCR is connected between the secondary of the transformer and a resistive load as shown in figure. The primary of the transformer is connected to a single phase supply and consider that load is of resistive.
During the positive half cycle of the input AC supply, thyristor T1 is forward biased, and when it is triggered at some firing angle though gate terminal, it starts conducting current to the load.
Since the SCR is a unidirectional device, it turns OFF during negative half-cycle. So the output voltage is produced only for positive half cycle.
The output power delivered by this half-wave rectifier is controlled by phase control, i.e., varying firing angle to the gate terminal. The load of this rectifier can be a RL load and RLE load with free wheeling diode.
Single Phase full-wave mid-point rectifier:
This converter rectifies both positive and negative half-cycles of the input supply. It uses two SCRs with center-tapped secondary transformer as shown in figure.
In positive half-cycle of the input supply, thyristor T1 is forward biased while T2 is reverse biased. WhenT1 is triggered, the supply voltage appear across the load.
It conducts till 180 degrees of input supply and turns OFF due to natural commutation. During negative half cyle, thyristor T2 is forward biased and when it is triggered, it starts conducting. It conducts till next positive half cycle.
The load could be RL or RLE depending on the type of application it is employed. This type converter produces an output voltage twice that of single phase half-wave rectifier.
These are essential when one of the terminals on DC side has to be grounded. However, a center-tapped transformer with a VA rating twice that of load is required and also high voltage rating thyristors are needed in this converter.
Single Phase full-wave bridge rectifier:
The circuit diagram of a full wave bridge rectifier using thyristors in shown in figure below. It consists of four SCRs which are connected between single phase AC supply and a load.
This rectifier produces controllable DC by varying conduction of all SCRs.
In positive half-cycle of the input, thyristors T1 and T2 are forward biased while T3 and T4 are reverse biased. Thyristors T1 and T2 are triggered simultaneously at some firing angle in the positive half cycle, and T3 and T4 are triggered in the negative half cycle.
The load current starts flowing through them when they are in conduction state. The load for this converter can be RL or RLE depending on the application.
By varying the conduction of each thyristor in the bridge, the average output of this converter gets controlled. The average value of the output voltage is twice that of half-wave rectifier.
Three-Phase Half-wave converter:
The output from single phase converter is small; when high power is required, three phase rectifiers are used. A three-phase half-wave rectifier with thyristors is shown in figure below.
The three-phase supply is given to this converter through a three-phase transformer with star connected secondary.
It works as similar to the three-phase diode bridge rectifier. In this, thyristor T1 is at highest positive anode voltage in the interval π/6 to 5π/6. During this interval, T1 can be made to conduct by giving a firing pulse to its gate.
This thyristor T1 continues to conduct till thyristor T2 is made to conduct in the interval 5π/6 < wt < 3π/2. Now the load current starts flowing through T2. Similarly, thyristor T3 is starts conducting once thyristor T2 is turned OFF.
In this, there are three pulses of output voltage during each complete cycle of supply voltage. Thus the ripple frequency is three times the supply frequency.
For this reason, this converter is also called as 3-pulse converter. This converter can be connected to different loads such as RL and RLE loads.
Three-Phase Full-wave converter:
It is obtained by connecting a DC terminal of two three-pulse converters in series. It is also called as 6-pulse bridge converter. This type converter is used in industrial applications where two-quadrant operation is required.
Here the load is connected via a three-phase half wave connection to one of three supply lines. Thus, there is no need of transformer; however, for isolation purpose a transformer is connected as shown in figure.
Here thyristors T1, T3 and T5 forms a positive group, whereas thyristors T4, T6 and T2 forms a negative group. And thus positive group SCRs are turned ON for positive supply voltage and negative group thyristors are turned ON for negative supply voltages.
In this, one of the thyristors from positive, whose anode voltage is maximum positive will conduct at any instant and simultaneously one of the thyristors from negative group, whose cathode voltage is maximum negative will conduct.
This converter can be connected to RL or RLE loads. By controlling the firing angle to respective thyristor, average power delivered to the load is changed.
The firing angle of particular thyristor in positive group measured from the instant when its anode becomes maximum positive.
Similarly, the firing angle for a thyristor in negative group is measured from the instant when its cathode terminal attains a maximum negative value.
- DC to DC converters:
Many DC operated applications need different levels of DC voltage from a fixed DC source.
Some of these applications include subway cars, DC traction systems, control of large DC motors, battery operated vehicles, trolley buses, etc. They require variable DC to produce variable speed, so a power conversion device is needed.
A DC chopper is a static device that converts a fixed input DC voltage to variable DC output or a fixed DC output of different magnitude (which can be lower or higher) than input value. The block diagram of a DC chopper is shown in figure below.
The chopper circuit is connected between DC input source and DC load. This chopper consists of power electronic switching devices such as thyristors which are connected in such a way that they produce required DC voltage to the load.
The output voltage is controlled by adjusting ON time of the thyristor (or switch) which turn changes the width of DC voltage pulse at the output. This method of switching is called as pulse width modulation (PWM) control.
The output of the chopper can be less or greater than the input and also it can be fixed or variable. These can be unidirectional or bidirectional devices based on the application it is intended for.
DC choppers are mainly used in DC drives, i.e., electric vehicles and hybrid electric vehicles.
DC choppers are classified into three basic types based on input and output voltage levels and are discussed below.
- Step-down Chopper or Buck Converter:
A step-down chopper produces an average output voltage lower than the input DC voltage. The circuit for this converter is shown in figure below.
Here the switching component is a thyristor that switches the input voltage to the load when it is triggered at particular instants.
A diode acts as a free wheeling diode that allows the load current to flow through it when thyristor is turned OFF. If this diode is absent, a high induced EMF in inductance may cause damage to the switching device.
The average output voltage of the converter is varied by controlling turn ON/OFF periods of thyristor. When thyristor is turned ON, the output voltage is same as the input voltage and if it is turned OFF, the output voltage is zero.
The output voltage is equal to (TON / T) Vin. So, by controlling the duty ratio K = (TON / T), the output voltage will be increased.
- Step-up Chopper or Boost Converter:
In this chopper, the output voltage is always greater than input voltage. The configuration of a boost converter is shown in figure below.
Here also a switch is used, which is connected in parallel with the load. This switch is a thyristor or an SCR.
As similar to the buck converter, a diode is placed in series with the load that allows the load current to flow when the thyristor is turned OFF.
When the thyristor is turned ON, the diode is reverse-biased and hence it isolates the load circuit from the source. So the inductor charges to the maximum input voltage source.
When the thyristor is turned OFF, the load gets the voltage from input as well as from inductor. So the voltage appearing across the converter output will be more than the input.
Here the output voltage is equal to (1/ 1 – d) times the input voltage, where d is the duty ratio (TON / T). By varying this duty ratio, the output voltage will be varied till the load gets desired voltage.
- Buck/Boost Converter:
This chopper can be used both in step-down and step-up modes by continuously adjusting its duty cycle. The configuration of buck-boost converter is shown in figure below that consists of only one switching device, i.e., one thyristor.
Along with an inductor and diode, additional capacitor is connected in parallel with this circuit.
When the thyristor is turned ON, the supply current flows to the inductor through the thyristor and induces the voltage in inductor.When the thyristor is OFF, the current in the inductor tends to decrease with the induced emf reversing polarity. The output voltage of this converter remains constant as capacitor is connected across the load.
By varying the value of duty ratio to a certain value, the output voltage is lower than the input voltage, typically in the range 0 ≥ k > 0.5, thus a buck converter.
And the output is higher than the input voltage if the duty ratio is in the range of 0.5 > K ≥ 1, thus acts as a boost converter.
- DC to AC Converters or Inverters:
These converters are connected between DC source of fixed input, and variable AC load. Most commonly, these DC to AC converters are called as inverters. An inverter is a static device that converts fixed DC supply voltage to variable AC voltage.
Here the fixed DC voltage is obtained from batteries or by DC link in most power electronic converter. The output of the inverter can be variable/ fixed AC voltage with variable/fixed frequency.
This conversion from DC to AC along with variable supply is produced by varying the triggering angle to the thyristors. Most of the thyristors used in inverters are employed with forced commutation technique.
These can be single phase or three phase inverter depending on the supply voltage. These converters are mainly divided into two groups. One is PWM based inverters and other multilevel inverters.
Further, these are classified voltage source inverter and current source inverter. Each type is subdivided into different types such as PWM, SVPWM, etc. Multilevel inverters are more popular in industrial applications.
The inverters overcome the drawbacks of PWM based inverters.
AC to DC Converter (Controlled Rectifier) :-
It's called the "onboard charger" though it really is a converter. It converts power from AC to DC and then feeds it into the car's battery. This is the most common charging method for electric vehicles today and most chargers use AC power.
DC to AC Conveter (Inveter) :-
The DC to AC conveter is required to convert the dc power to a sutaible ac power for electrical machine the power ouput from the battery pack (DC current) is converted using inverter to be used in electric motor (AC current)
Converts direct current (DC) from the battery to alternating current (AC) to be used by other devices such as the traction motor and coolant pump.
# Second Objective :
what is EV steady state speed if duty cycle is 70% and The other parameters of the electric vehicle is given below, Motor and Controller Parameters:
Rated Armature voltage= 72 V
Rated armature current= 400 A
Ra= 0.5Ω, KΦ= 0.7 Volt second
Chopper Switching frequency= 400 Hz
Theory :
V output = Vbattery * d ,where d is duty cycle
Then Voutpout substituted in equation of DC motor torque and speed
Where,
= angular speed in (radian/sec)
Ra = armature resistance
= motor constant (volt sec)
T = torque (Nm)
Then we get the equation sustituting the all the value and get the equation in terms of T and ω">ω of the motor
and Vehicle torque equation is given in terms of T and ω">ω
at steady state torque at vehicle and torque at motor is equal with that condition we find ω">ω
clear all
close all
clc
%% input paramater
fprintf("Input Parameter n")
Va = input("Enter the Va battery or Aremature voltage(volt) = ") ;
Ia = input("Enter the Ia Armature current (Ampere) = ") ;
Ra = input("Enter the Ra resistance (ohm) = ") ;
Kphi = input("Enter the Kphi motor constant(volt sec) = ") ;
d = input("Enter the d duty cycle (in percentage) = ") ;
f = 400; % chopper switching frequency (Hz)
%% duty cycle (d),Vo output voltage , Va battery voltage
d1 = d/100 ;% 70 percent
Vo = Va * d1 ;
%% Tm torque for motor and O omega angular speed
syms('Tm','O')
eqn = Tm == ((Vo - (O.*Kphi)).*Kphi)./Ra ;
s1 = solve(eqn);
fprintf("n")
fprintf("Equation of motor Tm = %s n",s1)
%% Tv torque for vehicle
% Tv = 24.7 +(0.0051*(O.^2));
eqn1 = 24.7 +(0.0051*(O.^2));
% at steady state Tm = Tv
syms('O')
eqn2 = s1 == eqn1 ;
s2 = vpasolve(eqn2,[O]);
s2rpm =(s2(2)*60)./(2*3.14);
fprintf("n")
fprintf(" EV steady state speed n if duty cycle is 70 percentage = %f radian/sec %f RPM",s2(2),s2rpm)
Result :
from the above result we get speed is 38.914983 radian/sec or 371.799198 in RPM
# Third Objective :-
model for the above equation :
Result :-
This result show torque speed curve for DC motor
# Forth Objective :
link of the blog :
https://www.tesla.com/blog/induction-versus-dc-brushless-motors
Wally Ripple is a long-time proponent of electric vehicles. Prior to joining Tesla Motors, he was an engineer at AeroVironment, where he helped develop the EV1 for General Motors and was featured in the documentary movie, Who Killed the Electric Car? Wally has also worked for the Jet Propulsion Laboratory on electric vehicle battery research, among other projects. In 1968, as a Caltech undergraduate student, he built an electric car (a converted 1958 Volkswagen microbus) and won the Great Transcontinental Electric Car Race against MIT.
In the beginning, the author describes the dominance of Internal Combustion Engines(ICE) in the world of automobile industry. He explains that all engines were similar and it was up to the user to select according to their requirement. Next, the author highlights topics related to EV technology especially related to DC Brushless Motor and Induction Motor.
According to him, DC Brush Motors is replaced by either DC Brushless Motor or Induction Motor. Also, the Lead Acid Battery is replaced by lithium-ion batteries for EVs.He also quoted that there will be the future of both the technology (DC Brushless Motor and Induction Motor) depends upon their demands and uses.
DC Brushless Motor:
With brushless machines, the rotor includes two or more permanent magnets that generate a DC magnetic field (as seen from the vantage point of the rotor). In turn, this magnetic field enters the stator core (a core made up of thin, stacked laminations) and interacts with currents flowing within the windings to produce a torque interaction between the rotor and stator. As the rotor rotates, it is necessary that the magnitude and polarity of the stator currents be continuously varied – and in just the right way - such that the torque remains constant and the conversion of electrical to mechanical energy is optimally efficient. The device that provides this current control is called an inverter. Without it, brushless motors are useless motors.
The author also said that a brushless DC motor produces no starting torque when directly connected to fixed frequency utility power. They really need the aid of an inverter whose “phase” is maintained in step with the angular position of the rotor.
Advantage:-
The advantage of DC Brushless Motor is that there is low heat generation in the rotor and its cooling capacity is better as compared to Induction Motor. Also, peak point efficiency is generally higher for this drive. The DC brushless drive can also operate at unity power factor, whereas the best power factor for the induction drive is about 85%. This means that the peak point energy efficiency for a DC brushless drive will typically be a few percentage points higher than for an induction drive.
Disadvantage:-
As Machine size grows, the magnetic losses increase proportionately and part load efficiency drops. Permanent magnets are expensive and difficult to handle due to very large forces that come into play when anything ferromagnetic gets close to them.
Induction Motor:
The technology behind the induction motor is that it basically uses a 3-phase induction motor which was invented by Nikola Tesla sometime before 1889. Unlike the DC brushless rotor, the induction rotor has no magnets – just stacked steel laminations with buried peripheral conductors that form a “shorted structure.” Currents flowing in the stator windings produce a rotating magnetic field that enters the rotor. In an Induction motor current interacts with the Magnetic field generated by the stator to produce a force which is required for rotor torque.
When a 3-phase induction motor is connected to utility type 3-phase power, torque is produced at the outset. The fact that induction motors are directly compatible with conventional utility power is the main reason for their success.
Advantage:-
The induction motor does not have any magnets and in this the B field is adjustable. The motor has the ability to start under load and there is no need of an inverter. In an induction motor B field is proportionate to V/f (Voltage to frequency). This technology is used to reduce the magnetic losses and conduction losses, due to which efficiency will remain at maximum peak. This all leads to increasing the performance, induction motor is very useful and efficient for high performance.
Disadvantage:-
An induction motor cannot operate from DC Voltage it always requires an AC voltage supply. In an induction motor, the Shaft speed is proportionate to line frequency. Hence, when used with utility power they are constant speed machines. When operated from utility power, they have limited starting torque and somewhat limited running peak torque capabilities, when compared to DC-type machines.
Inference:-
In the end, the author couldn't choose which drive is better than the other but makes it clear that DC Brushless motor drives will likely continue to dominate in the Hybrid and upcoming Plug-in hybrid markets and induction motor drives will likely maintain dominance for the high-performance pure electric.
Conclusion:
- We have discussed and studied the different types of power converter circuits employed in electric and hybrid electric vehicles.
- EV Steady-state speed of an EV Drivetrain was determined with the given input conditions.
- The Mathematical model for DC motor is developed.
- Lastly, we have studied a Blog on the Topic:-
Induction Versus DC brushless motors by'' Wally Rippel'', ''Nikola Tesla and explained in brief about the author’s perspective.