1. Design of new generation CLIQ units (CLIQ2)
J. Mourao TE-MPE-EE

2. Topics CLIQ2 Power supply Electronic Design Overview
1000VDC capacitor charger
Trigger signal generator circuit
Thyristor driver
User interface
User Safety measures
Trigger and discharge circuit redundancy
Redundancy check circuit
Conclusion

3. Overview Mains Input Trigger Circuit 1000VDC capacitor charger
Current supplied in the superconducting magnet
Capacitor Bank (non polarized) :
50[mF] charged at max. 1000V
max. stored energy 25 [KJoule]
Discharge circuit

4. Currently being designed & manufactured by SDS Performance
1000VDC capacitor charger
Currently being designed & manufactured by SDS Performance
technical specification:
Front Panel:
Boxed in a 3U/21TE Europe cassette (220mm deep)
100[mA] charging current to charge the 50[mF]capacitor bank to 1000V in 8 minutes
Front panel:
2 LCDs (Ucap, Icharge)
2 LEDs (end of charge, remaining capacitor Voltage > 40VDC)
1 commutator to select Charging voltage by steps of 100[V]
Rear connector (din41612, H15 Male):
Mains input 220 VAC
On/Off command controlling the output stage
2 digital outputs for(end of charge, Ucap>Utrim)
Analog reading of Ucap

5. Trigger signal generator circuit
To trigger the Power supply, the user as to release the 10VDC that he was continuously supplying
500[ms] pulse generator
12 [KHz] square Wave
500ms positive 12Khz pulse train

6. Thyristor driver
Two thyristors assembled in a single box. (ABB 5STB24N2800).
Gate current needed to fire the thyristors:
Current in the thyristor during the energy deposit (in the load):
Superconducting Magnet load

7. User interface Trigger input Front panel:
LCD monitoring: Ucap, Icap(charge current)
Led monitoring: Ucap>40V (RED), END of charge(GREEN)
Voltage setting: 0-500VDC by steps of 50 VDC (commutator)
Cap pressure ok LEDs
+24V OK LEDs
Trigger signal input
Trigger input signal (10 VDC)
2 Trigger presence leds
“Start charge” push button
“Equipment Stop” Buton
Trigger input
Rear panel:
Mains input (Burndy VDE)
Power output ()
Signal outputs:
Capacitor voltage (1:100)
Discharge current
End of charge
Internal problem contact

8. User safety measures Separation switch (lockable with a padlock)
ON/OFF Switch which automatically goes off after a power cut
Equipment stop button stop on the front panel of the unit
Interlock contact which opens when the capacitors switching crate is accessed
Remark: an automatic capacitor discharge is initiated when mains is turned off or is disconnected
Internal capacitors discharge function:
Discharge Time constant = 20[s]
After 3 time constants Ucap< 5% of initial voltage.
In the worst case(initial Ucap 1000V)-> After 1 [min] Ucap< 50VDC
5 x 2[kohm]/ 800W Resistor banks (4000 Watts total)

9. Trigger and discharge circuit redundancy
Two 24 VDC powersuplies
Two trigger circuit generators(on the same board)
Two pulse transformers boards
Two pairs of thyristors
Redundancy check idea:
Use two 800A (cheap) coils to measure the presence of current in a pair of thyristors
The coils will saturate above 800A (we expect current in the order of 6000A)
But we will know if current passed in both branches

10. Redundancy check circuit 1
CLIQ1 power supply discharge test V discharge
CH1 (yellow): Iout measured by CLIQ internal TI
CH2 (blue): Iout measured by CT max80
CH3 (pink): Iout measured by Talema 800A (TI_1)
CH4 (green): Iopen wire measured by Talema 800A (TI_2)
Max current ~ 1400A on a 50V discharge
500V discharge

11. Redundancy check circuit 2
CHA (red): Uout measured by Talema CT (through a 9.4ohm burden resistor)
CHB (blue): U after filter stage
50 V 80mF discharge
500 V 80mF discharge

12. Redundancy check circuit 3
To be able to detect the failure of one of the 4 thyristors we may finaly use a circuit like this one.

13. Thanks for you attention !
Conclusion
Thank to a big team (Mathieu Favre, Samuel Deleage, Stavroula Balampekou, Boshidar Panev,…) the First CLIQ 2 unit will be ready in two weeks.
It will allows us to make discharge at 1000V and see how the current is shared between the two thyristor branches.
Than we can define the best way for checking the redundancy state.
Thanks for you attention !