DESC:FIELD OF INVENTION
The present invention relates to method to operate electric devices on electrically propelled vehicles, monitoring operating variables, e.g., temperature, speed, or energy consumption. More precisely control methods that enables continuous operation of the electric vehicle in the event of one or more sensor failure.
BACKGROUND OF THE INVENTION
In general, most electric vehicle contains a power source like a battery or fuel cell, battery for supplying electric power, a 3-phasemotor, speed sensors installed on that motor, a control system comprised of several sensors to measure temperature, voltage, current and speed. The temperature sensor determines the ambient temperature, the motor temperature, and the battery temperature. The current sensors for detecting current that flows through the winding of said motor and current coming from the battery. The voltage sensors for detecting voltage at the winding of said motor and voltage coming from battery. The speed sensor to measure the acceleration and velocity of the vehicle and motor. The control system propels the vehicle in response to signals received from a plurality of sensors which generate sensor measurements indicating the operating condition of the vehicle. In general, if such sensors fail, the output deviates from a control target this can damage the motor and cause a vehicle breakdown or in some cases the control system will shut down the vehicle to prevent any damages. At present in the event of a sensor failure the vehicle shuts down to prevent damage to the motor even though the vehicle is in operational condition.
In US patent number 8,977,416 B2 discloses a vehicle control system that will provide continuous operation of the electrical vehicle if control system is malfunction by providing a sub control system. The sub control system will diagnose the measurements from sensors and if it detects malfunction, it will cut off the main control system and assume the role of the main control system. The limitation with this system is that if one or more sensor fails then the sub control system will not be able to provide a continuous operation and will shut down the vehicle.
One of the important measurements for continuous operation of an electrical vehicle is the current measurement in the system and motor. In US patent application publication US2011/0288699A1 the focus was on the measurement from the controls motor torque based on feedback current provided by the current sensors and if that malfunction then from a calculated slip value. The system is limited to only current sensor failure and there are other parameters like temperature that can lead to vehicle breakdown.
In a US patent application publication US20180281597A1 a redundancy of vehicle control system and mutual monitoring of the redundant systems is used to ensures a safer driving system. The system is directed towards torque, torque is calculated by various systems and cross checked by redundant systems to prevent an incorrect torque being applied by cutting off the signal. This system does not provide a method to keep a continuous motion during sensor damage, best it could do is shutdown the vehicle in case of unusual torque reading.
OBJECTS OF THE INVENTION
The principal object of this invention is providing a fault-tolerant system that enables continuous operation of the electric vehicle without a redundant control system in the event of one or more sensor failure.
Another object of the invention is a method to reconfiguring measurements from sensors for a certain parameter to compensate for the failed sensor for a different parameter to estimate an operating condition for the vehicle.
Yet another object of the invention is to indicate sensor failure to the driver and optimise vehicle propulsion to prevent breakdown after one or more sensor failure.
SUMMARY OF THE INVENTION
The invention relates to a method to keep an electric vehicle in optimum operating condition using an adaptive control system in case of sensor failure.
In one embodiment a control system receives measurements from all temperature sensors, motor speed sensor, system current sensor, the system voltage sensors. In an event one or more temperature sensor fails the control system takes certain steps to estimates and supplements the measurements for the failed sensor. In the event of the ambient temperature sensor fails, the control system switches to measurements from the processor temperature sensor and set it as ambient temperature. In an event ambient temperature and processor temperature sensor fails the control system set the ambient temperature at a max value and take the max values as ambient temperature. In the event motor temperature sensor fails, the processor estimates motor temperature with the motor thermal estimator algorithm and sets an estimated motor temperature. In the event controller temperature sensor fails, the processor estimates controller temperature with the controller thermal estimator algorithm and sets an estimated controller temperature. And at the same time the processor runs the thermal derating algorithm to determine an optimum operation condition for the vehicle and limit the driver input to the optimum operation condition. The motor thermal estimator algorithm uses the efficiency map for motor, the system current sensor measurements, the system voltage sensors measurements, the motor speed sensor measurement, and the ambient temperature measurements to estimate the motor temperature. The controller thermal estimator algorithm uses the efficiency map for controller, the system current sensor measurements, the system voltage sensors measurements, the motor speed sensor measurement, and the ambient temperature measurements to estimate the controller temperature. The efficiency map for motor is a three-dimensional look up table that can indicate efficiency of the motor based on speed and input power, and the controller efficiency map for controller is a two-dimensional look up table that can indicate the efficiency of the Controller based on motor speed and input power. Further in the event of a sensor failure the control system will indicate a sensor failure on interface unit to the driver.
In another embodiment the control system can also keep the electric vehicle in operating condition in case of a current sensor and/or voltage sensor failure. All current and voltage sensors sent their measurements to the control system to render an optimum operating condition for the vehicle. In the event one or more current and/or voltage sensor fails the control system takes certain steps to estimate and supplement the measurements for the failed sensor. In the event input battery current measurement shows an error, the processor will estimate input battery current from all three phases of the motor. In the event input battery voltage measurement shows an error, the processor will estimate input battery voltage from voltage at all three phases of the motor. In the event one of the motor phases current measurements shows an error, the processor will estimate the current from the phase that showed error by the current measurement of the other two motor phases. In the event one of the motor phase voltage measurements shows error, the processor will estimate the voltage from the phase that showed error by the voltage measurements of the other two motor phases. In the event more than one motor phase current measurements show error, the processor samples the input current at three different unique instances of the Pulse-width modulation (PWM) system’s control timing cycle and estimates phase currents. In the event a measurement error occurs the control system estimates an optimum operating condition for the vehicle based on a controller efficiency map stored in the processor. The controller efficiency map is based on dynamometer setup and power analyser test conducted on the control system.
In yet another embodiment the adaptive control can also keep the electric vehicle in operating condition in case of motor speed measurements show error. Hall effect sensors placed in the motor sent measurements to the control system and the processor determine the position of the motor shaft. In the event the motor speed measurement show error, the processor determines the speed of the motor based on the position measurements from the hall effect sensors. In the event the accelerometer measurement show error, processor estimates acceleration using measurements from hall sensors. In the event one or more hall sensors measurements show error and at least one hall sensor(s) is functioning correctly, the processor estimates the motor shaft position and speed based on the measurements from the functioning hall sensor(s). In the event all the hall sensor fails, the processor uses the motor phase current, motor phase voltage, and a position estimating algorithm to estimate the motor shaft position.
The adaptive control system is designed for small vehicles like two or three wheeled vehicles with limited sensors, preventing unexpected breakdown by substituting measurements for failed sensors through other mean.
BRIEF DESCRIPTION OF THE DRAWINGS
This invention is illustrated with the help of the accompanying drawings, which demonstrate the process steps involved in various process trials carried under certain preferred embodiment under the invention as well as the findings.
Fig 1 – A block diagram illustrating the components of an electrical vehicle and how they are interacting with each other.
Fig 2 – Temperature sensor failure detection system.
Fig 3 – Current sensor failure detection system when battery current or the phase current shows an error.
Fig 4 – Current sensor failure detection system when two or more phase current sensor show error.
Fig 5 – Voltage sensor failure detection system.
Fig 6 – Speed and acceleration sensor failure detection system.
DETAILED DESCRIPTION OF THE INVENTION
The present invention discloses an adaptive control system and a method to keep an electric vehicle in optimum operating condition in case of a sensor failure. The control system enables continuous operation of an electric vehicle in the event of one or more sensor failure/malfunctions. In an electric vehicle a control system (which is also the drive system) receives measurements from a plurality of sensors. Based on the measurement received from each sensor the control system determines if the vehicle is in an optimum operating condition. Continuous operation of an electric vehicle depends on the availability of measurements from multiple sensors positioned throughout the electric vehicle. Without proper measurements or outputs from the sensors a control system cannot determine the optimum operating condition of the vehicle, this can lead to vehicle breakdown. In the present invention the control system determines an optimum operating condition for the vehicle and based on the measurements received from the sensors and the control system propels the vehicle under the optimum operating condition based on the input provided by a driver through an input interface (connected to the control system). In case of a sensor malfunction, the control system calculates a theoretical measurement for the malfunctioning sensor based on the inputs from other sensors and based on the theoretical measurement a new optimum operating condition is determined and enable continuous operation of the vehicle. At the same time the control system indicates the driver by means of a digital display, sound, or light indication that there is a failure in one or more sensor and the vehicle should be taken to a service station. The system increases the reliability of the vehicle without increasing the extra cost on multiple redundant sensor and control system.
‘Electric Vehicle’ herein refers to terrestrial vehicle which may be wheeled (mono-wheel, two-wheeler, three-wheeler, four-wheeler), tracked, railed, or skied, watercrafts such as boats, boats, ships, barge, hovercraft or submarines, and air crafts such as plane, helicopter, or drones. Wherein the vehicle is powered partially (e.g., hybrid) or complete by an electric motor. The system is best suited for small or light weight vehicles with limited circuitry to keep the cost minimum, such as a three wheeled vehicle.
‘Control system’, ‘drive system’ ‘motor controller’ and ‘system’ herein refers to the same system if not specified otherwise. Control system comprises of a processer, which includes a CPU, a RAM, a ROM, and an input interface. The system receives data from plurality of sensors, the system has a memory which stores programmes and optimum range for each sensor and other parameters. The control system is part of the powertrain of the electric vehicle.
In a preferred embodiment a 48pin LQFP package, Flash memory, 32KB ROM, 4KB RAM, 8KB DATA FLASH, with 32Mhz speed, and 16-bit CISC architecture microcontroller is used as a control system.
Optimum operating condition of a vehicle in context of this invention is the range for each parameter under which the vehicle will not break down. For instance, parameter could be temperature, current speed and so on, for example, an optimum temperature range under which a motor, the PCB (on which the control system is built on) or a battery can function, optimum current range is the range the current can reach in the system or motor. These ranges can be different for different vehicles based of the motor, power capacity and other factors. Once these ranges are established by testing, they can be stored in the processor for the system to run.
An ‘error’ or a ‘sensor failure’ in the context of this specification means that the measurements provided by a sensor are beyond the expected range or there is no measurement to sample.
In one embodiment a method to keep an electric vehicle in optimum operating condition using an adaptive control system in case of a temperature sensor malfunction is disclosed. To manage and detect temperature of the vehicle circuits and motor a control system is connected to plurality of temperature sensors. The control system receives temperature measurement from said sensors, each of the temperature sensors are being configured to sample temperature measurement from various positions in the vehicle. The control system could receive measurements from the sensor on PCB for ambient temperature, temperature measurement from the processor of the control system, temperature measurement from the sensor on the controller (MOSFET) heat-sink, temperature measurement from the sensor mounted inside the stator coil of the motor, and temperature measurement from the battery. Each temperature sensor measures temperature in an operational range, if the measurement from the sensor is within the operational range the sensor is said to be functioning. The optimum range measurement is stored in the processor of the control system as reference value, the system detects if a sensor measurement is going beyond the operational range by comparing the measurement sampled from each sensor with their respective reference value at specific time interval. In case of abnormal measurement change during a time interval or measurements existing out of operational range of the scope of temperature sensor system categorizes this as sensor failure/malfunction/error. On failure of any one or more temperature sensor(s) the control system calculates and estimates an optimum measurement of temperature of the failed sensor based on the speed of the vehicle, power generated by the motor, temperature from other functioning sensors, time integral, and data from motor efficiency map. Further, on failure of one or more temperature sensor the control system sends an indication to the driver by means of a digital display, light, sound, or a combination there of. Further, on failure of one or more temperature sensors the control system may limit the performance of the electric vehicle for continuous operation and avoid breakdown of the vehicle based on the calculated estimate optimum measurement.
In an embodiment, as shown in Fig-1, the control system has two temperature sensors which are used to measure ambient temperatures one is mounted on a printed circuit board which is inside casing of control system (Ts-1) and other is internal to a processor (Ts-2) mounted on the PCB. System primarily uses Ts-1 for the measurement as the sensor internal to the processor Ts-2 will have slightly higher value due to losses in the processor itself. Both the sensors are sampled at a defined time interval. The processor in system converts the voltage output from sensor to temperature measurement. In case of abnormal measurement change during the time interval (e.g., rate of change of sensor is more than a set value) or measurements existing out of operational range the system categorizes this as sensor failure. In the event of Ts-1 failure system changes the dependency to Ts-2 and estimates a measurement for Ts-1 based on. In the event of both Ts-1 and Ts-2 failure system prefixes the ambient temperature as worst condition and considers max value the ambient temperature can go up to. As shown in Fig-1 control system has one temperature sensor to measure motor winding temperature (Ts-3) which is mounted inside the stator coil of the motor. In case of abnormal measurement change during the time interval or measurements existing out of operational range of the system categorizes this as sensor failure. On failure of Ts-3 sensor the system uses a Thermal estimation algorithm to find the approximate maximum temperature of the motor. Motor thermal estimation algorithm uses the following parameters for estimation:
1. Ambient temperature,
2. Motor Input power,
3. Motor Speed,
4. Time interval,
5. Motor efficiency map, and
6. Motor Thermal resistance
Motor Input power = Input average DC voltage × Input average DC current × motor efficiency
Motor efficiency map is a 3D look up table stored inside a processor which can give efficiency of the motor based on speed and input power. This efficiency is used to find the losses of the motor at the operating point.
Losses in Motor = Motor input power × (1- Motor efficiency).
based on this motor settling temperature (the temperature where any heat producing element will saturate and keep a constant temperature after a long period of operation) is estimated using the following equation:
Motor temperature = (Losses in Motor × Motor Thermal resistance) + Ambient temperature
Motor Thermal resistance for a given motor is a constant which is stored inside the control system. Based on the calculated motor temperature performance of the vehicle is reconfigured for continuous operation and to prevent any vehicle brake down. Further, on failure of one or more temperature sensor the control system sends an indication to the driver by means of a digital display, light, sound, or a combination there of on the interphase unit.
As shown in Fig-1 control system has one temperature sensor to measure Controller heat-sink temperature (Ts-4) which is mounted on a heat-sink attached to Controller. In case of abnormal measurement change during the time interval or measurements existing out of range of the scope of temperature sensor system categorizes this as sensor failure. In the event Ts-4 failure, system uses a Thermal estimation algorithm to find the approximate maximum temperature of the Controller. Controller thermal estimator uses the following parameters for estimation:
1. Ambient temperature,
2. Controller Input power,
3. Motor Speed,
4. Time interval,
5. Controller efficiency map, and
6. Controller Thermal resistance.
Controller Input power = Input average DC voltage × Input average DC current.
Controller efficiency map is a 2D look up table stored inside the processor which can give efficiency of the Controller based on motor speed and input power. This efficiency is used to find the losses in the Controller at the operating point.
Losses in Controller = Controller input power × (1- Controller efficiency)
based on this MOSFET/Controller heat-sink settling temperature is estimated using the below equation.
Controller heat-sink temperature = (Losses in Controller × Controller Thermal resistance) + Ambient temperature.
Controller Thermal resistance is a constant which is stored inside the control system. Based on the calculated Controller heat-sink temperature the performance of the vehicle is reconfigured for continuous operation and to prevent any vehicle brake down. Further, on failure of one or more temperature sensor the control system sends an indication to the driver by means of a digital display, light, sound, or a combination there of on the interface unit.
In another aspect of the invention is a method to determine and optimise the operating condition of the vehicle in an event when any of the current sensor(s) or the voltage sensor(s) show error/fail/malfunction. The control system samples all current and voltage sensors measurements to render an optimum operating condition for the vehicle. Input battery voltage and current is supplied to the system via CAN (CAN - Controller Area Network is a common communication network between different electronic control elements in a vehicle) communication by the internal Battery Management System of the battery pack. The control system samples measurements from the system current sensors, wherein at least one current sensor to measure the input battery current, current measurements from the motor, wherein the motor is a three phase motor and at least one current sensor for each phase of the motor, and the system voltage sensors, wherein at least one voltage sensor to measure input battery voltage and at least one voltage sensor on each phase of the motor to measure voltage. In an event the input battery current measurement shows an error, the processor will estimate input battery current from all three phases of the motor. All the three-phase currents can be combined to find the average input battery current.
In an event the input battery voltage measurement shows an error, the processor will estimate input battery voltage by the voltage measurement from phases of the motor. In case of input voltage sensor failure system calculates the input average voltage from phase voltage measurement using the below equation.
Input average voltage = v2 x Phase average voltage.
In an event any of the motor phase voltage sensors fails system continues normal operation as phase currents are enough to keep the system operating under normal condition. In this condition the system will issue warning to the user and keep calculating the average motor phase voltage.
In an event one of the motor phases current measurements shows an error, the processor will estimate the current from the phase that showed error by the current measurement of the other two motor phases. The control system uses a three-phase motor on which two phase current sensors are enough for a normal operation as the algebraic sum of currents will be zero (Iu + Iv+ Iw = 0). The 3rd phase current sensor acts as a failsafe mechanism in case one of the other two sensors fail.
In an event more than one motor phase current measurements show error, the processor samples the input current at three different unique instances of the Pulse-width modulation (PWM) system’s control timing cycle and estimates phase currents. The processor estimates an optimum operating condition for the vehicle based on a controller efficiency map stored in the processor and all the measurements it samples from all the current and voltage sensor. As the system measures three phase voltages these voltages and currents can be multiplied to find the input power of the motor. Efficiency of the controller is tested at different points and mapped as a controller efficiency map in the system. Once the motor input power and efficiency are known controller input current can be calculated from the below equations:
Controller input power = Motor input Power / Efficiency of controller.
Controller input average current = Controller input power / Controller input voltage (measured by the system).
The control system samples the input current at 3 different unique instances of the Pulse-width modulation (PWM)control timing cycle which will result the input current being equal to two of the phase currents at two instances and third instance will be averaged to find the input average current this acts a failsafe mechanism in case two or all three phase current sensors of the system fails. A dynamometer setup and power analyser and measure the controller efficiency at different operating points, this data is tabulated to make a lookup table and stored in the processer.
In the event the system find an irregularity in the Controller input average current or voltage the performance of the vehicle is reconfigured for continuous operation and to prevent any vehicle brake down, in such events the processor may or may not derate the performance of the motor. Further, on failure of one or more current sensor the control system sends an indication to the driver by means of a digital display, light, sound, or a combination there of on the interface.
In an event when there is an error in the acceleration measurement or motor speed measurement, this could be due to the failure in MEMS accelerometer/gyroscope or more hall speed/position sensor in the motor. If hall sensor fails maximum optimal torque cannot be achieved at the starting point.
Another aspect of the invention is the detection of hall sensor failure and managing the propulsion of the vehicle. There are three hall sensor position sensors provide the system information above motor rotor angle position with an accuracy of 60 degree. In case of one hall sensor failure system starts the motor with remaining 2 sensors output values once the motor starts rotation failed sensor signal can be reconstructed as the time between the transition of all three-hall position sensors are same. In an event accelerometer fails the control system can directly measure the speed from hall sensor, and the acceleration is a direct calculation from speed.
In case of two or more motor hall speed/position sensor fails, control system engages the motor to start with an open loop strategy where voltages are applied to the motor at a fixed time period ignoring speed/position sensor information, during this operation control system will ensure safe phase and input currents to the motor. Once the motor starts operation phase currents and phase voltage measurement are processed by the system through a position estimation algorithm where motor back electromotive force (Bemf) values can be estimated this equation uses motor phase resistance and inductance. This estimator works on the principle that during steady state condition magnetising element of motor current will be zero.
V = Rs × I + Ls ×d I/dt + Bemf
Rs and Ls are motor phase resistance and Inductance, respectively. once the estimator can create the speed/position information operation will switch to this. During this operation speed and torque of the motor will be reduced to ensure part safety.
The equations to find the speed and angle from motor currents in case of all hall sensor failures.
Ea = Va - Rs Ia - Ls d Ia/dt
Eß = Vß - Rs Iß - Ls d Iß/dt

Ed = Ea Cos? + Eß Sin?
Eq = Ea Sin? + Eß Cos?

Speed (Velocity) estimated = (Eq - (sgn of Eq) ×Ed).

In an embodiment, as shown in Fig 6, the control system samples measurements from the accelerometer and hall sensor (inside the motor) to determine the speed and position of the vehicle, in an event accelerometer measurement shows error the system switches to hall sensor measurements and the processor based on the hall sensor measurement estimates the acceleration of the vehicle. In case the hall sensor fails, the control system will apply voltage to the motor at fixed time period, control system will ensure safe phase and input currents to the motor. Once the motor starts operation phase currents and phase voltage measurement are processed by the system through a position estimation algorithm to estimate the motor position. This control system may derate the operating condition of the vehicle to ensure continuous operation.
In an embodiment step to keep the electric vehicle in operating condition in an event where the motor speed measurements show error and/or accelerometer measurement show error and/hall sensors show error. In an event the motor speed measurement show error, the processor determines the speed of the motor based on the position measurements from the hall effect sensors. In an event the accelerometer measurement show error, processor estimates acceleration using measurements from hall sensors as shown in Fig 6. In an event one or more hall sensors measurements show error and at least one hall sensor(s) is functioning correctly, the processor estimates the motor shaft position and speed based on the measurements from the function hall sensor(s). In an event all the hall sensor fails, the control system applies voltages at fixed time period to the motor ignoring speed/position sensor measurement, during this operation control system will ensure safe phase and input currents to the motor. Once the motor starts operation phase currents and phase voltage measurement are processed by the system through a position estimation algorithm. Wherein, the processor runs a derating algorithm to determines an optimum operation condition for the vehicle and limit the driver input to the optimum operation condition. Further, on failure of one or more speed/position/hall sensor the control system sends an indication to the driver by means of a digital display, light, sound, or a combination there of on the interface.
The above specification is illustrative and not restrictive. Many variations of the disclosed method and system will become apparent for a person skilled in the art upon review of the specification.
References
US 8977416 B2; 2013-May-09; Park et al.
US20110288699A1; 2011-Nov-24; Jang et al.
US20180281597A1; 2018-Oct-04; Herb.
,CLAIMS:We claim:
1. A method to keep an electric vehicle in optimum operating condition using an adaptive control system in case of a temperature sensor failure, control system comprises of a at least a processer, stored in the processor are:
a motor thermal estimator algorithm;
a controller thermal estimator algorithm;
a thermal derating algorithm;
an efficiency map for motor; and
an efficiency map for controller;
wherein, the control system samples measurements from;
a) an interface unit for receiving vehicle control inputs from a vehicle driver for operation of the vehicle;
b) plurality of temperature sensors, wherein there is at least one ambient temperature sensor, a processor temperature sensor, at least one motor temperature sensor, and at least one controller temperature sensor;
c) a motor speed sensor, placed inside a motor;
d) a system current sensor; and
e) a system voltage sensor;
wherein the method includes the following steps:
in an event of the ambient temperature sensor fails, the control system switches to measurements from the processor temperature sensor and set it as ambient temperature; in an event ambient temperature and processor temperature sensor fails the control system set the ambient temperature at a max value and take the max values as ambient temperature, wherein the max value is the maximum temperature the process can sustain;
in an event motor temperature sensor fails, the processor estimates motor temperature with the motor thermal estimator algorithm and sets an estimated motor temperature; and
in an event controller temperature sensor fails, the processor estimates controller temperature with the controller thermal estimator algorithm and sets an estimated controller temperature;
wherein, the processor runs the thermal derating algorithm to determines an optimum operation condition for the vehicle and limit the driver input to the optimum operation condition.
2. The method as claimed in claim 1, wherein the motor thermal estimator algorithm uses the efficiency map for motor, the system current sensor measurements, the system voltage sensors measurements, the motor speed sensor measurement, and the ambient temperature measurements to estimate the motor temperature; and the controller thermal estimator algorithm uses the efficiency map for controller, the system current sensor measurements, the system voltage sensors measurements, the motor speed sensor measurement, and the ambient temperature measurements to estimate the controller temperature.
3. The method as claimed in claim 1 and 2, wherein the efficiency map for motor is a three-dimensional look up table that can indicate efficiency of the motor based on speed and input power, and the controller efficiency map for controller is a two-dimensional look up table that can indicate the efficiency of the Controller based on motor speed and input power.
4. The method as claimed in claims 1 to 3, wherein in the event of a sensor failure the control system will indicate a sensor failure on the interface unit.
5. The method as claimed in claims 1, wherein the control system comprises a pulse-width modulation (PWM) system in the processer, wherein the control system samples measurements from:
(a) the system current sensors, wherein at least one current sensor to measure the input battery current, current measurements from the motor, wherein the motor is a three phase motor and at least one current sensor for each phase of the motor; and
(b) the system voltage sensors, wherein at least one voltage sensor to measure input battery voltage and at least one voltage sensor on each phase of the motor to measure voltage;
wherein in an event any of the current sensor(s) or the voltage sensor(s) shows error the method further comprises of following step:
in an event the input battery current measurement shows an error, the processor will estimate input battery current by combining the current measurement from all three phases of the motor;
in an event the input battery voltage measurement shows an error, the processor will estimate input battery voltage by combining the voltage measurement from all three phases of the motor;
in an event one of the motor phases current measurements shows an error, the processor will estimate the current from the phase that showed error by the current measurement of the other two motor phases; and
in an event more than one motor phase current measurements show error, the processor samples the input current at three different unique instances of the Pulse-width modulation (PWM) system’s control timing cycle and estimates phase currents
wherein, the processor runs a derating algorithm to determines an optimum operation condition for the vehicle and limit the driver input to the optimum operation condition.
6. The method as claimed in claims 5, wherein if a current and/or voltage measurement error is established the processor estimates an optimum operating condition for the vehicle based on a controller efficiency map stored in the processer.
7. The method as claimed in claims 6, where in the controller efficiency map is based on dynamometer setup and power analyser test conducted on the control system.
8. The method as claimed in claims 7, wherein the control system further comprises a position estimating algorithm stored in the processer, and the control system samples measurements from:
(a) at least one hall effect sensor configured inside a motor, wherein the hall effect sensor measurements are sent to microcontroller and the processor determines the position of the motor shaft;
(b) an accelerometer; and
(c) the motor speed sensor;
wherein the method further comprises steps to keep the electric vehicle in operating condition in an event where the motor speed measurements show error and/or accelerometer measurement show error,
in an event the motor speed measurement show error, the processor determines the speed of the motor based on the position measurements from the hall effect sensors;
in an event the accelerometer measurement show error, processor estimates acceleration using measurements from hall sensors;
in an event one or more hall sensors measurements show error and at least one hall sensor(s) is functioning correctly, the processor estimates the motor shaft position and speed based on the measurements from the function hall sensor(s); and
in an event all the hall sensor fails, the processor uses the motor phase current, motor phase voltage, and a position estimating algorithm to estimate the motor shaft position
wherein, the processor runs a derating algorithm to determines an optimum operation condition for the vehicle and limit the driver input to the optimum operation condition.
9. The method as claimed in claim 1 to 8, wherein the control system is for an electric three or two wheel vehicle.