description: parameter identification and testing of ... · brake machine : induction machine, ......

Laboratorio di Macchine elettriche e azionamenti - LEMAD CIRI MAM UO ARM – Centro Interdipartimentale per la Ricerca Meccanica Avanzata e Materiali Università di Bologna

Claudio Rossi Ph.+39-0512093564 [email protected] 13/07/12 1/17

Description: Parameter identification and testing of induction motor for

traction application Customer: MONTE-CARLO-RENT

ESPLANADE DES PECHEURS 98 000 MONACO

Quotation: n. 274 of 11/09/2013 Order: 12/09/2013 Table of Content:

1. Introduction

2. Description of the test bench instrumentation

3. Electric drive under test

3.1 Inverter and battery supply

3.2 Motor characteristics

3.3 Motor parameters

4 Test results

5 Comment

Bologna September 16th 2013

The tester Claudio Rossi



1. Introduction This report shows the results of the test carried out on September 13rd, 2013 at the laboratory of the CIRI MAM at the University of Bologna, for evaluating the performance of low voltage induction motor, given by the customer. All the equipment for supplying the motor, breaking and measuring the motor performances are set up by the CIRI MAM unit. The test aims to evaluate the performance of the motor for different reference current, over a wide speed range. 2. Description of the test bench instrumentation

Torque meter Staiger Mohilo 0160 DM 'L' 500.

Max. torque 500 Nm,

Basic accuracy 0.2.

Brake machine : Induction machine, 37 kW OEMER QL 200 C

Brake control: EEI vector control. Speed regulated in the range 0-4800rpm

Three-phase wattmeter: YOKOGAWA WT2030.

Basic accuracy 0.02%

DC wattmeter: YOKOGAWA WT210.

Basic accuracy 0.1%

AC current transducers: n. 3 LEM IT-700-S ULTRASTAB.

Max. current 700A.

Basic accuracy 50ppm

DC current transducer: LEM IT-400-S ULTRASTAB.

Max current 400A

Basic accuracy 50ppm



3. Electric drive under test 3.1 Inverter and battery supply

Battery type 32 cells LIFePO, TS-160AHA, connected in series.

Battery rated voltage 104 V

Battery rated capacity 160 Ah

Inverter type integrated system ‘EOS traction’, equipped with program for direct control of torque. Absolute torque reference sent by PC through USB-CAN communication protocol.

Inverter rating VDCMAX=120 [V]; Iout_rated=150 [ARMS], Iout_MAX=350 [ARMS]

Motor control algorithm: Sensored Indirect Field Oriented Control

Inverter firmware DSP2812_AUTOTNG_NTWRKSLV_IM_LMD120V450A_V120P_VR100

BMS 4 slave modules TBE type ‘LEMAD-PASS_BMS_8C REV R2’



3.2 Motor characteristics The motor was given by the customer. Ready for installation on the test rig. The main motor characteristics are given in Tab. I.

Tab. I Motor characteristics

Manufacturer ---

Model ---

Type Induction motor

Stator winding type ---

Rotor type ----

Weight 27 [kg]

Length ---

Outer diameter ---

Frame Die cast aluminum

Ventilation NO

Pole pair 2

Rated voltage (line-to-line) 70 [VRMS]

Encoder Hengxiang K76-J2N200B20

Pulse per turn 200

Supply voltage 5 [V]

Output type Open collector



3.3 Motor parameters

The electrical main parameters of the AC machine have been determined by means of a test sequence, called ‘Autotuning’ carried out at the test bench, by using the same inverter, supplied by the same batteries that will be both used during the performance test. The ‘Autotuning’ sequence is composed by 5 main step:

1. At zero speed for the measurement of the stator resistance. 12 points are measured.

2. At high speed for measurement of stator inductance. 51 points are measured.

3. At standstill for the measurement of stator leakage inductance. 51 points are measured.

4. At high speed for the measurement of rotor time constant. 12 points are measured.

5. Data averaging and computation of the main parameter of the machine model and FOC.

Autotuning test condition are given in Tab.II. The motor parameter calculated by Autotuning are given in Tab. III. These parameters have been used in the control algorithm of the inverter for the performance test.

Tab II Test condition for ‘autotuning’ procedure

Reference stator current [ARMS] 135

Maximum speed [nMAX] 4000

Average DC voltage [VBATT] 104

Inverter MOSFET temperature TINV1,2,3 [°C] 45

MOSFET type

IRF4321

Dead time ON (SVMNL->DdTmOn) [ms] 2,600

Dead time OFF (SVMNL-> DdTmOff) [ms] 2,600

Rise time (SVMNL->TmRise) [ms] 0,400

Fall time (SVMNL->TmFall) [ms] 0,400

RDSON Mosfet (SVMNL->Rt) [mohm] 1,000

Vo Mosfet (SVMNL->Vot) [V] 0,000

RAK diode (SVMNL->Rd) [mohm] 0,833

Vo diode (SVMNL->Vod) [V] 0,300

Switching frequency [Hz] 5500



Tab. III Motor parameters

Phase stator resistance Rs [m] 14,0320

Phase rotor resistance Rr' [m] 4,4937

Stator inductance Ls [mH] 0,8982

Magnetizing inductance Lm [mH] 0,8576

Leakage inductance LS=(LS-LM2/LR) [mH] 0,0794

Leakage coefficient

0,0884

Stator time constant LS/RS [s] 0,0057

Magnetizing current Im [ARMS] 62



5. Test results The following diagrams represents the characteristics of the drive system obtained in four different tests:

1. at a reference stator current of 135 [ARMS]



4. at low speed at increasing stator current up to 350 [ARMS]



Fig. 1 Aggregate results with constant stator current reference I=135ARMS.

Fig. 2 Mechanical output power (blue) , inverter output power (red), battery output power (green) with statore currente reference I=135ARMS.



Fig. 3 Mechanical output torque with three different reference stator current: 135ARMS (green); 270ARMS (red); 350ARMS (blue).



Fig. 4 Mechanical output power with three different reference stator current: 135ARMS (blue); 270ARMS (red); 350ARMS (green).



Fig. 5 Electric battery power with three different reference stator current:

135ARMS (blue); 270ARMS (red); 350ARMS (green).



Fig. 6 Real stator current for three different reference stator current: 135ARMS (blue); 270ARMS (red); 350ARMS (green).



Fig. 7 Real DC voltage for three different reference stator current: 135ARMS (blue); 270ARMS (red); 350ARMS (green).



Fig. 8 Evaluated motor efficiency for three different reference stator current: 135ARMS (blue); 270ARMS (red); 350ARMS (green).



Fig. 9 Evaluated motor losses for three different reference stator current: 135ARMS (blue); 270ARMS (red); 350ARMS (green).



Fig. 9 Output torque vs. stator current at 100 [rpm]



5 Comment 1 In the test carried out at the maximum current of 350A an unusual behavior of the input power and efficiency is reported. It is highly probable that it is due to the large voltage drop across the batteries (about 14%) in heavy overload condition. It affects so much the motor performance, because of the motor is entering in the flux-weakening region.

description: parameter identification and testing of ... · brake machine : induction machine, ......

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