System and Method for Reducing Speed Ripple of Drive Motor of Electric Vehicle

Content Provider	The Lens
Abstract	A system and method for reducing drive motor speed ripple of an electric vehicle are provided. The system includes an inverter that converts DC power supplied from a battery to AC power and supplies the AC power to the drive motor by inverter switching. A resolver is configured to detect a speed of the drive motor and a position of a rotor, a signal generator includes a microcontroller that is configured to generate a square wave signal. An integrator is configured to convert the square wave to a sine wave, and apply a sine-wave excitation input signal to the resolver. Furthermore, a motor controller is configured to operate the inverter through a PWM signal, adjust the frequency of the excitation input signal to prevent the inverter switching frequency of the inverter and the peaks of an output voltage signal sampled for speed calculation from overlapping.
Related Links	https://www.lens.org/lens/patent/012-199-579-055-592/frontpage
Language	English
Publisher Date	2019-06-11
Access Restriction	Open
Content Type	Text
Resource Type	Patent
Jurisdiction	United States of America
Date Applied	2017-12-28
Agent	Mintz Levin Cohn Ferris Glovsky and Popeo, P.c. Peter F. Corless
Applicant	Hyundai Motor Co Ltd Kia Motors Corp
Application No.	201715856889
Claim	A system for reducing drive motor speed ripple of an electric vehicle, comprising: an inverter configured to convert direct current power supplied from a battery to alternating current power and configured to supply the alternating current power to the drive motor by inverter switching; a resolver configured to detect a speed of the drive motor and a position of a rotor; a signal generator including a microcontroller configured to generate a square wave signal and an integrator configured to convert the square wave to a sine wave, and configured to apply a sine-wave excitation input signal to the resolver; and a motor controller configured to operate the inverter through a PWM signal, adjust the PWM signal and the excitation input signal to be synchronized by setting a frequency of the PWM signal to be a multiple of a frequency of the excitation input signal, wherein the inverter is time-delayed as compared to a sampling time of the PWM signal, resulting in dead time periods where inverter switching does not occur, the inverter including an upper switch and a lower switch that are prevented from being simultaneously turned on and off, and wherein when the PWM signal and the excitation input signal are synchronized, peaks of the excitation input signal are positioned in the dead time periods where the inverter switching does not occur. The system of claim 1 , wherein the motor controller is configured to select the peaks detected from the excitation input signal when calculating the speed of the drive motor using the resolver. A method for reducing a drive motor speed ripple of an electric vehicle, comprising: generating, by a processor, a square wave using a signal generator; generating, by the processor, an excitation input signal by converting the square wave to a sine wave; applying, by the processor, the excitation input signal to a resolver; operating, by the processor, the inverter through a PWM signal; and adjusting, by the processor, the PWM signal and the excitation input signal to be synchronized by setting a frequency of the PWM signal to be a multiple of a frequency of the excitation input signal, wherein the inverter is time-delayed as compared to a sampling time of the PWM signal, resulting in dead time periods where inverter switching does not occur, the inverter including an upper switch and a lower switch that are prevented from being simultaneously turned on and off, and wherein when the PWM signal and the excitation input signal are synchronized, peaks of the excitation input signal are positioned in the dead time periods where the inverter switching does not occur. The method of claim 3 , further comprising: generating, by the processor, an output voltage signal by applying the excitation input signal to the resolver; sampling, by the processor, peaks of the output voltage signal for speed calculation; and calculating, by the processor, speed using the sampled peaks of the output voltage signa
CPC Classification	Propulsion Of Electrically-Propelled Vehicles ;Supplying Electric Power For Auxiliary Equipment Of Electrically-Propelled Vehicles ;Electrodynamic Brake Systems For Vehicles In General ;Magnetic Suspension Or Levitation For Vehicles;Monitoring Operating Variables Of Electrically-Propelled Vehicles;Electric Safety Devices For Electrically-Propelled Vehicles CONTROL OR REGULATION OF ELECTRIC MOTORS; ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS;CONTROLLING TRANSFORMERS; REACTORS OR CHOKE COILS Climate Change Mitigation Technologies Related To Transportation Conjoint Control Of Vehicle Sub-Units Of Different Type Or Different Function;Control Systems Specially Adapted For Hybrid Vehicles;Road Vehicle Drive Control Systems For Purposes Not Related To The Control Of A Particular Sub-Unit
Examiner	Bickey Dhakal Said Bouziane
Extended Family	032-514-405-947-892 006-835-696-731-788 080-476-341-828-961 156-697-152-606-264 121-844-975-517-243 012-199-579-055-592 088-524-267-952-968
Patent ID	10315530
Inventor/Author	Lim Jae Sang Rho Jeongwon Kang Gu Bae Kim Young Un
IPC	B60L3/00 B60L15/08 B60L15/20 B60W20/17 H02P27/08 H02P29/50
Status	Active
Owner	Hyundai Motor Company Kia Motors Corporation
Simple Family	088-524-267-952-968 012-199-579-055-592
CPC (with Group)	B60L3/0038 B60L15/08 B60L15/20 B60L2210/40 B60L2240/421 B60L2270/145 B60L2270/147 H02P27/08 H02P29/50 Y02T10/64 Y02T10/72 B60L15/2045 B60W20/17
Issuing Authority	United States Patent and Trademark Office (USPTO)
Kind	Patent/New European patent specification (amended specification after opposition procedure)