DC / DC 400 V / 12 V Constrains Specifications Design Tests Paul Timmer WP F,L,H

Constrains Switch on 350 V Switch off320 V Vmax in 400 V Vout10 < U < 14 V Pout< 20 W Isolation Vin-Vout 4 kV Environmental; Lifetime15 y Failure rate< 10 % Oil MIDEL 7131 Test pressure60 MPa

400V to 12V Purpose: - provide galvanic barrier between OM and VEOC - convert voltage from VEOC voltage to OM voltage - provide over current protection 380V 12V Galvanic barrier fuse Principle: controller Disable startup current Feedback On > 350V off < 315V RectifierLoad pwr curr. volt Breakout Box outer shell DC/DC converter Fiber storage Optical & electrical connector to OM ET - P.Timmer A.Berkien, MT – GJ.Mul

Diagram

400 V / 12 V Realisation v.01

Test plan Technical Specifications Environmental Specifications Reliability calculations Tests to check the specifications and the limits Can it stands the environmental behaviour Prediction of the failure rate

Input to output voltage behaviour

Start up Voltage: 2V/Div DC coupled (green) Current: 500mA/Div. Measured with current probe (purple).

Voltage, current pictures Voltage: 50mV/Div. AC coupled (green) Current: 500mA/Div. Measured with current probe (purple).

Shorting current picture Voltage: 2V/Div DC coupled (green) Current: 2A/Div Measured with current probe (purple).

Power and efficiency

Overall efficiency

Environmental validation cycle for DC/DC converter Temperature (storage period, not active) Ambient > -10 °C (20 °C/15 min) 1 h stay (> time constant) -10 °C > +60 °C (20 °C/15 min) 1 h stay, Temperature shock +60 °C > ambient, in 10 min Vibration, mechanical shocks Random vibrations from 1 Hz to 55 Hz according the 3 axes (X, Y, Z) amplitude: 1 G duration: 15 min on each axe DOM not powered Visual inspection between each axe Mechanical shocks according the 3 axes (X, Y, Z) Amplitude/duration: 15 G / 20 ms / ½ sinusoide Numbers: 16 shocks Directions: 6; +/- 0X; ; +/- 0Y; ; +/- 0Z; DOM not powered Visual inspection between each axe Temperature (active mode) Ambient > +10 °C, 1h, > +40 °C, 1h, > ambient (active) Pressure 1 > 600, 1h, >1 (not active) Active test at ambient Temperature -10 °C _ +60 °C Temperature Shock  T=50 °C Vibration Temperature +10 °C _ +40 °C Pressure 60 MPa Start with working DC/DC End with working DC/DC

Pressure tests

Temperature tests 1 ComponentP=7 WP=10 WP=15 W Control IC °C Transformer core °C Rectifier control IC5715 °C ΔTΔT

Temperature tests 2 Vin 375 V P load 15 W after2 h: T ambient19.5 °C T transformer top 38.5 °C T transformer coil 41.5 °C (These absolute values are measured with PT100 temperature sensors).

Reliability calculations

Conclusion Ready for PRR (as good as) Pending Ideas to improve the transformer (make it easier to manufacture) Mechanical tests (vibration)