A Link Capacitor Design for On-Board Charger in Electric Vehicle

Transcription

1 EVS28 KINTEX, Korea, May 3-6, 2015 A Link Capacitor Design for On-Board Charger in Electric Vehicle Dongyoon, Noh 1 DAS Center Engineering Design Team 4, Mando, 619 Sampyeong-Dong, Bundang-Gu, Seongnam-Si, Gyeonggi-Do, Korea, dongyoon.noh@halla.com

2 Introduction 1. In order to charge an EV battery charger requires an OBC 2. Typical OBC is composed a two-stage AC/DC converter 3. It is composed of a DC/DC converter for isolation, charging and PFC for the power factor correction 4. Link capacitor using a high voltage in order to minimize the loss is essential 5. However, the electrolytic capacitor life is dependent on the ambient temperature, ESR and heat according to temperature and current ripple. 6. In this paper, it proposes the optimum design, fault diagnosis and life prediction method for 6.6kW OBC with high voltage electrolytic link capacitor 2

3 About OBC I. About the OBC (On-Board Charger) 1. Diagram J1772 BMS EVSE On-Board Charger High Voltage Battery 110/220Vac Transformer Isolation power transfer Io DC Curren 3

4 Specfication I. Spec. of On-Board Charger Division Items Unit Specifications Input Input Voltage V rms AC 80V ~ 275V Input Frequency Hz 45 ~ 70 Max. Power kw 6.6 Output Output Voltage V DC 270 ~ 413 Max. Output Current A 25A Temperature Storage Temperature C -40 ~ 105 Operating Temperature C -40 ~ 85 Environment Protections Cooling IP Grade - IP6K9K Vibration/Shock G 4.5 / 30 Cooling Type - Water-cooled Max. flow rate lpm water Max. 65 EMC EMS/EMI - Radio Freq./Conduction/Radiation Dimensions Size mm 340 * 350 * 100 Weight Kg 15 4

5 Structure I. Structure of On-Board Charger Items Ass y OBC Ass y Product Control B/d Link CAP Inductor/Trans. AC Filter B/d Power B/d Switching 소자 5

6 역율 Performance I. Performance of OBC 1. Max efficiency : 92% 2. Power factor : 99% or more 3. High Density : over 0.6 [kw/l] 4. EMC ECER Satisfied CE Certification completed The Power efficiency according to the load 출력전력 [kw] The Power factor according to the load Vin=220Vav 6

7 ACR(N :Circle1,N :Circle1) [mohm] ACL(N :Circle1,N :Circle1) [nh] Analysis of Link capacitor PCB Inductance Curve Info long ACL(N :Circle1,N :Circle1) Setup1 : Sw eep m1 Name X Y m m m Freq [khz] Resistance long Name X Y m m m m Curve Info ACR(N :Circle1,N :Circle1) Setup1 : Sw eep Freq [khz] 50kHz 100kHz L (nh) R (mohm)

8 ACR(N :Circle1,N :Circle1) [mohm] ACL(N :Circle1,N :Circle1) [nh] Analysis of Link capacitor PCB Name X Y Inductance_Net m m Curve Info short ACL(N :Circle1,N :Circle1) Setup1 : Sw eep m m Freq [khz] Resistance_Net short Curve Info ACR(N :Circle1,N :Circle1) Name X Y Setup1 : Sw eep1 m m2 m m Freq [khz] 50kHz 100kHz L (nh) R (mohm)

9 Simulation (PSIM) Ripple Current of Capacitor Frequency Domain Current per Frequecy 9

10 Life of Capacitor I. Electrolytic capacitor life calculated according to the temperature conditions 1. Objective : calculating the life by predicting operating temperature pattern 2. Standard elements : 150uf, 450Vdc, 19EA 3. Temperature definition 1) Cooling water temperature = each country temperature + 2 (Assuming the air to flow into the radiator coolant temperature saturated with air temperature) 2) The ambient temperature = Temperature inside the engine = cooling water temperature + 30 (After driving, the temperature inside the engine is assumed to be higher than the air temperature) 10

11 Life of Capacitor I. Calculation I I f 1 I f 2 I fn f 0... F f 1 Ff 2 Ffn T X I f 0 2 ( ) T I 0 0 L X L r 2 TO TX T 10 2 O T 5 X - Lx : Life estimation (hour) - Lr : the maximum guarantee time due to ripple current - T0 : Capacitor upper limit temperature - Tx : Actual capacitor ambient temperature - Δ T0 : an increase coefficients in the internal temperature - Δ Tx : actual internal temperature rise - If0 : complex ripple calculated - Io : Irms flowing per capacitor - Ffn : Frequency multiplier for ripple current - Ifn : Frequency domain current 11

12 Life of Capacitor 1. Case 1 : Korea Criteria 1) Based on seasonal temperatures PM 2) Quarterly seasonal temperature is the maximum temperature Design margin objectives 3) Result : Electrolytic capacitor life : over 15 years Spring Summer Autumn Winter Water cooling Temp. Ambient Temp. ( ) Operating ratio(%) Morning Noon night Morning Noon night Morning Noon night Morning Noon night Seoul in korea low high Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

13 Life of Capacitor 1. Case 1 : World Criteria 1) Based on seasonal temperatures PM 2) Quarterly seasonal temperature is the maximum temperature Design margin objectives Egypt Pakistan New Delhi kenya Iran Las vegas Greece Singapore Low High Low High Low High Low High Low High Low High Low High Low High Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

14 Life of Capacitor 1. Case 1 : World Criteria 1) Result : Electrolytic capacitor life : over 15 years Water cooling Temp. Ambient Temp. ( ) Operating ratio(%) Morning Spring Noon night Morning Summer Noon night Morning Autumn Noon night Morning Winter Noon night Final Result : 1) Satisfied for more than 15 years endurance 2) Life time of electrolytic capacitor expected Region LIFE TIME CASE 1 Korea Over the 15 years CASE 2 World Over the 15 years 14

15 Link capacitors diagnostic I. Link capacitors diagnostic and predictive sequence method 1. As the capacitor is aging, the capacitance value, tan, leak current, ESR change. 2. Using this internal impedance change are also possible fault diagnosis and life prediction 3. Check the link capacitor voltage profile is possible fault diagnosis and life prediction method. Link Capacitor Voltage Time Estimation of capacitor state 15

16 Link capacitors diagnostic I. Link capacitors diagnostic and predictive sequence method 1. As the OBC is charging, the link capacitor voltage rises as a fixed sequence. 2. After the charging voltage of the link capacitors is dropped into 0V 3. Because the voltage drop to the profile associated with an internal impedance of the capacitor is changed according to the state of the capacitor life 4. Can check the current status of this change in voltage profile about link capacitor failure and state, as well as the lifetime can be predicted. 16

17 Conclusion 1. In this paper, we consider the ESR and capacitance values were the OBC simulation 2. Using data derived through the simulation to estimate the life of the capacitor 3. And Proposed a way to predict the diagnosis and lifetime of the capacitor using voltage profile 4. After a check into the link capacitor life in the OBC, including Korea, the world meets the expected endurance 15 years in urban and common areas. 17