EEE 602: Advances in Electrical Engineering

Dr. Mongkol Konghirun

Department of Electrical EngineeringKing Mongkut’s University of Technology Thonburi

Electric Motor DrivesThe improvement in terms of control algorithms

and estimation techniques over a wide range of operating speeds for the following major types of motors:

(a) Induction Motor (IM)(b) Permanent-Magnet Synchronous Motor

(PMSM)(c) Brushless DC Motor (BLDC)(d) Stepping Motor(e) Switched Reluctance Motor (SRM) … Etc.

Research Topics Research potentials:

(a) Zero and low-speed control performance

(b) Rotor position and speed estimations at zero speed

(c) Field weakening (extremely high-speed) control

(d) Fast braking control (regenerative braking)… Etc.

Drive Strategies Induction motor:

(a) V/f control(b) Sensored/sensorless vector control(c) Sensored/sensorless direct torque control

Permanent-magnet synchronous motor:(a) Sensored/sensorless vector control(b) Sensored/sensorless direct torque control

Brushless dc motor:(a) Sensored/sensorless trapezoidal control

… Etc.

Motor Drive System

(2)Power

Converter

Rectifier (AC-DC) Chopper (DC-DC) Inverter (DC-AC) Cycloconverter (AC-AC)

(1)Digital

Controller

Computer Microprocessor Microcontroller Digital signal

processor

Feedbacks: Current (electrical) Voltage (electrical) Speed (mechanical) Position

(mechanical)

Commands: Torque Speed Position

Induction motor PM Synchronous motor Brushless DC motor Stepping motor Switched reluctance

motor DC motor, etc.

wr Te

Tload

(3)Motor

(4)Load

Constant torque Constant power Variable torque

sensorless system

Constant torque

speed

Load torque

hoist

conveyor

elevator

speed

Load torque

Constant power

paper winder

speed

Load torque

Variable torque

Fan (x=2)

roller (x=1)

Load torque speedx

pump (x=2)

Motor Load

trainvehicle

ApplicationsV/f control of Induction motor (Inverter)

Air conditioner(Energy saving)

Washer

Water pump(Energy saving)

Treadmill

Blower (Energy saving)

ApplicationsVector control of PM Synchronous motor

Blower (Energy saving) Sewing machineWheelchair

Applications

CNC machine

Centrifuge(up to 100,000 rpm)

Vector control of PM Synchronous motor

Mitsubishi - Inverter pump

Mitsubishi - Inverter pump

Mitsubishi - Inverter pump

Mitsubishi - Inverter pump

Mitsubishi - Inverter pump

Mitsubishi - Inverter pump

Hitachi - Inverter pump

Hitachi - Inverter pump

Hitachi - Inverter pump

Hitachi - Inverter pump

Hitachi - Inverter pump

Hitachi - Inverter pump

GE fan & blower (Regal-Beloit)

GE fan & blower (Regal-Beloit)

12-pole BLDC motor(4 poles/segment)

BLDC motor (Reliance Electric)

Fasco pool pump (imPower)

Fasco pool pump (imPower)

Fasco pool pump (imPower)

Fasco pool pump (imPower)

Applications

Hybrid car Electric car

Plug-in hybrid car

Applications

Energy Diversification of EVs

Ref : K.T. Chau, Electric Vehicle Machines and Drives: Design, Analysis and Applications, IEEE Wiley, 2015.

Benefits of EV1. Diversification of energy

resources.2. More overall energy

efficiency.3. Regenerative brake energy.4. Zero harmful emissions.

A Review of Electric Motors in Commercial All-EVs (1969-2012)

Ref : J. de Santiago et. al., Electrical Motor Drivelines in Commercial All-Electric Vehicles: A Review, IEEE Transactions on Vehicular Technology, February, 2012.

In 2012, IMs were still the predominant traction motors with less than 75% efficiency.

DC motors are still in use in some small vehicles.

PM, RM, and SBM present better performance than IM.

Price of raw materials for PM will determine if PM motor will become the standard technology.

SPM = Synchronous permanent magnet motorSBM = Synchronous brushed motorRM = Reluctance motorIM = Induction motorDC = DC motor

Surfaced-Mounted and Interior PM Motor Drive for EV Applications

Ref : G. Pellegrino et. al., Performance Comparison Between Surface-Mounted and Interior PM Motor Drive for Electric Vehicle Application, IEEE Transactions on Industrial Electronics, February, 2012.

The performance of surface-mounted and interior PM motors with same outer diameter (216 mm) and stack length (170 mm) was investigated at given 50-kW continuous power at 12,000 rpm max. speed & 173% current overload.

A comparison results were based on Finite Element analysis (FEA).

SPM & IPM : giving the same continuous power

SPM : concentrated windings making a simpler construction. Output power cannot overcome its rating independently of the applied current overload. Extra copper losses for de-exciting the PM flux at high speeds.

IPM : good overload capability over entire speed range. Higher copper losses at low speeds.

Loss Minimization of a Surface-Mounted Permanent-Magnet Motor

Ref : J. Wang, X. Yuan, and K. Atallah, Design Optimization of a Surface-Mounted Permanent-Magnet Motor With Concentrated Windings for Electric Vehicle Applications, IEEE Transactions on Vehicular Technology, March, 2013.

The energy loss minimization of fractional-slot concentrated-winding surface-mounted permanent-magnet motor was focused over the driving cycle.

14-pole vs 12-pole (same 12 slots) : The 14-pole give less flux/pole allows lower iron losses & lower copper losses in field weakening due to higher machine inductance.

Increasing machine inductance by means of increasing number of turns with the axial length proportionally reduced in order to keep net flux linkage unchanged.

Power Density Maximization of an Interior Permanent-Magnet Motor

Ref : A.M. EL-Refair et al, Advanced High-Power-Density Interior Permanent Magnet Motor for Traction Applications, IEEE Transactions on Industry Applications, September/October, 2014.

12-slot/10-pole interior permanent-magnet motor with nonoverlapping concentrated windings and spray cooling stator end winding (3rd prototype) was optimized.

Novel spoke rotor structure/assemble was presented, providing flux-concentration effect (improving torque/power density).

Finite Element analysis (FEA) was tool for mechanical analysis (stress distribution), electromagnetic analysis (demagnetization & loss study), and thermal analysis (temperature distribution on rotor & stator).

Spoke-Type Ferrite Magnet Motor for Low-Speed EV

Ref : S-I Kim, J. Cho, S. Park, and S. Lim, Characteristics Comparison of a Conventional and Modified Spoke-Type Ferrite Magnet Motor for Traction Drives of Low-Speed Electric Vehicles, IEEE Transactions on Industry Applications, November/December, 2013.

Spoke-type interior PM is mainly designed to increase airgap flux density by the flux concentration principle. So, the ferrite magnet was adopted in 10-pole, 12-slot motor for low-speed EV.

The rotor design concerned with the reduction of PM demagnetization by means of increase of ferrite magnet thickness & structure of two divided magnet segments.

In-Wheel Surface-Mounted Permanent-Magnet Synchronous Motor

Ref : S-U Chung, S-H Moon, D-J Kim, and J-M Kim, Development of a 20-pole – 24-slot SPMSM with Consequent Pole Rotor for In-Wheel Direct Drive, IEEE Transactions on Industrial Electronics, January, 2016.

Advantages of in-wheel motor are• Freeing-up space by removing conventional mechanical

components. • All-wheel independent control for improved vehicle

dynamics and increased vehicle design freedom.

A technical challenges are low cogging torque, low torque ripple, high torque density, high efficiency, and wide-speed range capability.

The design of 20-pole/24-slot, outer-rotor SPMSM with epoxy resin encapsulation and water cooling was proposed with the limited space inside the wheel. The FEA was the main tool.

Novel 6-phase, 18-slot, 8-pole IPM Synchronous Motor for EV

Ref : V.I. Patel et al, Enhanced Availability of Drivetrain Through Novel Multiphase Permanent-Magnet Machine Drive, IEEE Transactions on Industrial Electronics, January, 2016.

Novel fractional-slot winding configuration with high reluctance torque capability and reduced stator MMF space harmonics content.

Drivetrain incorporating redundancy and safety with just one motor, leading to lower footprint, cost saving, and high reliability.

Enhance availability in the event of open-circuit/short-circuit fault in one or two phases of a single three-phase system.

Intelligent Condition Monitoring via Wireless Control

Ref : T.M. Jahns, Interior PM Synchronous Machines Historical Perspectives, Current Status, and Future Directions, JMAG Users Conference2009, 2009.

http://powerelectronics.com/power-electronics-systems/inverters-fight-traction

Load detectionRotor PM demag. detectionTemperature monitoring Baring health monitoringShorted winding detection

Magnetic & Mechanical Gear

Ref : T.V. Frandsen et al, Motor Integrated Permanent Magnet Gear in a Battery Electrical Vehicle, IEEE Transactions on Industry Applications, March/April, 2015.

Advantages of magnetic gear are :• Reduce acoustic noise and vibration• Peak torque transmission capability• Inherent overload protection (harmlessly slipping)• No lubrication or mechanical contact except the bearings• Reduce maintenance and improve reliability

FEA was used to design the motor integrated PM magnetic gear to achieve high torque density and high efficiency.

Rotating high-speed low-pole PM flux is modulated by segment cylinder. The torque of output low-speed high-pole PM rotor would be induced for mechanical power transfer within motor integrated PM gear.

Advanced Control for Induction Motor Drives in EV

Ref : W. Sung, J. Shin, and Y.-S. Jeong, Energy-Efficient and Robust Control for High-Performance Induction Motor Drive With an Application in Electric Vehicles, IEEE Transactions on Vehicular Technology, October, 2012.

Indirect rotor-flux-oriented control of an induction motor was implemented with • Parameter identification (no-load & locked rotor tests)• Flux compensation (current map based MTPA control over rated flux control)• Torque-response improvement (fast response of flux control)• Voltage compensation due to load disturbances• Temperature compensation (stator-temperature based rotor resistance tuning)

Lower output torque (10-15%) was observed due to temperature gap between stator and rotor parts. Temperature compensation may need to be improved.

Current map-based MTPA control is suitable from the aspects of energy efficiency and robustness.

Fail-Safe Operation with Position Sensor Fault Diagnosis & Fault-Tolerant Control

Ref : F. Mwasilu and J.-W. Jung, Enhanced Fault-Tolerant Control of Interior PMSMs Based on an Adaptive EKF for EV Traction Applications, IEEE Transactions on Power Electronics, August, 2016.

Adaptive Extended Kalman Filter (EKF) estimation algorithm handles process and measurement noises.

Position sensor failure is identified by continuously monitoring the difference between estimated position/speed and measured values.

Fault-Tolerant Operation : Two-Level & Three-Level Traction Inverter

Ref : A. Choudhury, P. Pillay, and S.S. Williamson, Comparative Analysis Between Two-Level and Three-Level DC/AC Electric Vehicle Traction Inverters Using a Novel DC-Link Voltage Balancing Algorithm, IEEE Journal of Emerging and Selected Topics in Power Electronics, September, 2014.

Advantages of three-level inverter are :• Low switching losses at higher switching frequencies • Low acoustic noises• Low-voltage rating and voltage stress of power switches• Reduced total harmonics distortion (%THD) of inverter’s output voltage, reducing

electromagnetic interference (EMI)• Fault-tolerant capability from power switch failure

Vehicle-to-Home (V2H)

Ref : A. Emadi, Advanced Electric Drive Vehicles, CRC Press, 2015.

In order to implement V2H, the circuit topologies of on-board charger technology (AC-DC or DC-DC converter) must be bidirectional power flow.- from grid to vehicle => charging battery (buy electricity)- from vehicle to grid => discharging battery (sell electricity or home use)

Optimization techniques in energy controller are the key tools for total energy cost minimization in residential microgrid.

Range anxiety (RA) is defined as the fear of running out of battery energy for EV before the destination has been reached.

Vehicle-to-Grid (V2G)

Ref : M. Yilmaz and P.T. Krein, Review of the Impact of Vehicle-to-Grid Technologies on Distribution Systems and Utility Interfaces, IEEE Transactions on Power Electronics, December, 2013.

V2G system consists of 6 subsystems:

Energy resources or electric utility

Independent system operator (ISO) or aggregator

Charging infrastructure and locations

Two-way electrical energy flow and communication between EV and ISO (or aggregator)

On-board and off-board intelligent metering and control (i.e., smart meter)

On-board battery charger and management

V2G is integrated with smart grid.V2G enables the sustainable energy.

Ancillary Services : Key V2G Benefits

Ref : M. Yilmaz and P.T. Krein, Review of the Impact of Vehicle-to-Grid Technologies on Distribution Systems and Utility Interfaces, IEEE Transactions on Power Electronics, December, 2013.

V2G aggregators are expected to collect EVs into a group to create a larger, more desirable load for the utility. The V2G system can provide higher quality ancillary service than are currently available

1) Quick frequency control : fast charging/discharge power from/to the grid from EV battery (balancing real power)

2) Quick voltage control : fast balancing supply and demand for reactive power compensation (selecting current phase angle)

3) Load leveling and peak power management : load shifting by means of electricity pricing algorithm

4) Effective spinning reserve : fast extra connected generating capacity by EV battery when needed

5) Renewable energy supporting and balancing : buffer and store energy generated by intermittent wind & solar plants.

With V2G, the EV users are able to make the efficient use and can minimize their own electricity costs.

V2G Challenges

Ref : M. Yilmaz and P.T. Krein, Review of the Impact of Vehicle-to-Grid Technologies on Distribution Systems and Utility Interfaces, IEEE Transactions on Power Electronics, December, 2013.

Bidirectional V2G for ancillary service is likely to reduce the battery life : EV battery degradation due to temperature, rate of energy withdrawn, discharge depth, and cycling frequency. (Users’ perspectives)

With large EV penetration, additional distribution power losses, voltage deviations, harmonic distortion, and peak demand are concerned. (Utility’s perspectives)

Additional investment on infrastructure is required to serve the extra EV demand in large underground cables and overhead lines, more transformer capacity, charging stations, etc. (Government’s perspectives)

ApplicationsElectric train (AC traction motor)

Electric train (Maglev)

BTS MRTAARL

Rolling stockAC Electrification System

Ref : Siemens

DC Electrification SystemReceiving substation

Medium Volt SW

Rectifier TransformerDC SW

Rec

Medium SW

Third rail

National grid

DC Electrification System

51

Bulk Substation,BSSor Receiving Substation,RSS : Receives electricity from Utilities (MEA or PEA)

Traction Substation,TSS : supplies electricity to rolling stock or train

Service Substation,SSS : supplies electricity to station buildings and other systems

Ref : Siemens

DC Electrification System : Earthing

52

BS EN 50522:2010 : Earthing of power installations exceeding 1 kV a.c.

AC Electrification SystemNational grid Receiving substation

Medium Volt SW

AC Electrification System : Earthing

54

BS EN 50522:2010 : Earthing of power installations exceeding 1 kV a.c.

AC Electrification System : Feeding Systems

55

Lower voltage drop is expected. Traction substation can supply longer distance.

Direct-fed System

AC Electrification System : Feeding Systems

56

Railway Electrification/Traction Simulation Tool

การอบรม Sitras Sidytrac โดย Mr. Martin Altmann ผู้ เช ี่ยวชาญ

บริษัท Siemens วันท ี่ 7-16 พย 2560

HomeworkFind one example of motor drive application or

product that you think it is innovative. Give the following information:

Picture. Describe this application (product). Describe how are motors used ? What kind of motors (if found) ? Webpage link where you found.

Personal Transporter

Use five gyroscopic (measuring direction in space) sensors to balance the transporter both forward and backward directions.

Use microprocessors based control of two PM motors (one for each wheel).

http://www.segway.com/

EEE 602: Advances in Electrical Engineering

Dr. Mongkol Konghirun

Department of Electrical EngineeringKing Mongkut’s University of Technology Thonburi