OEM Tech NBU-0808 Discharge Circuit User Manual

OEM Tech NBU-0808 Discharge Circuit

Overview / Applications

• The NBU-0808 discharge circuit is designed for simplification of solid-state laser systems development. The module forms quasi-rectangular pulses on a flashlamp using energy stored in external capacitors bank. The module includes IGBT, its driver, protective circuits, simmer and trigger circuits and controls.
• The module doesn’t include embedded discharge resistors, although includes all the necessary circuits to control them. Discharge resistor assemblies of different size and resistance can be purchased as accessories by us.
• Let us emphasize, NBU-0808 is not a stand-alone solution. For proper operation it requires capacitor charging power supply and capacitor bank as well as some minor parts and controls.

• By default, NBU-0808 includes capabilities both for serial and external triggering (See Triggering section for details). Simplified as well as more complex modifications are available on request.

Safety

• Important feature of NBU-0808 is a clear and visible separation between low voltage and high voltage parts. 24V power input and all interface circuits (SIM and PWF) are separated from high voltage circuits with 4mm creepages and solid insulation of 2500VAC test voltage (1 MOOP/MOPP).

Cooling

• The module is cooled with a built-in fan.
• No external cooling is required.

Appearance

Connections, signals, signal descriptions

CAPACITOR BANK CONNECTION: Two M5 terminals

• C+ – to the capacitor bank positive
• C– – to the capacitor bank negative

FLASHLAMP CONNECTION: Two M5 terminals

• L+ – to the flashlamp positive (i.e. to the flashlamp anode)
• L– – to the flashlamp negative (i.e. to the flashlamp cathode)

CAPACITOR CHARGER CONNECTION CONSIDERATIONS
Note: we recommend connecting capacitor charging power supply not to C+/C– terminals, but straight to the capacitor bank.

EXT (TO THE TRIGGER TRANSFORMER): Molex 39-30-1020
By default, NBU-0808 supports both serial and external methods of triggering. To use NBU-0808 for external triggering, a trigger transformer should be connected to the EXT connector. If EXT connector is left unconnected, NBU-0808 will automatically recognize this and apply pulses of serial triggering to L- flashlamp connection (see also Triggering section for details).

Once a trigger transformer is connected, trigger pulses will be automatically applied to the EXT connector instead of L- flashlamp connector.

Trigger pulse parameters:

·         350V by default, other on request

·         ~20mJ by default, other on request

2 (-)

|

TRIGGER

DR (TO DISCHARGE RESISTORS): Molex 39-30-1020

·         PIN1 is always under the same potential as C+

·         PIN2 is commutated by embedded relay and follows Discharge signal of PWF connector

Please do not exceed the peak and the average discharge current (500mA).

2 (-)

|

RELAY

We suggest using NBU-0808 with discharge resistors of your choice. The resistance and the power rating of discharge resistors must be selected accordingly to your application. Real operating voltages, your capacitor bank capacitance and the required quick discharge time are the most important parameters affecting the choice. You are welcomed to contact us for the assistance.

24VDC (TO 24VDC POWER SUPPLY): Molex 39-30-1020

1 (-)

|

+24VDC

| Supply power to the control circuits of NBU-0808 as well as to the integrated simmer supply module

·         Voltage: 24VDC

·         Current: 5A max (up to 10A peak)

2 (-)| +24VDC Return| Return of 24VDC power supply

PWF (PULSE CONTROL): Molex 39-30-1040

1 (-)

|

Discharge

| While 0V voltage is applied to PIN1 (or PIN1 is unconnected), i.e. while Discharge is ON , capacitor battery continuously discharges on discharge resistors connected to DR connector of NBU-0808.

Be careful, while Discharge is ON the capacitor charging is prohibited and capacitor charging power supply must be disabled.

While +5V voltage is applied to PIN5 ( Discharge is

OFF ) module can be operated in the regular way.

2 (-)| Not Connected| –

3 (-)

|

Pulse

| Duration of +5V TTL pulse at PIN3 completely defines IGBT-key open state time and, as consequence, flashlamp pulse duration
4 (-)| Interface Return| Return of Pulse and Discharge signals

PWF CIRCUITS

SIM (SIMMER SUPPLY CONTROL): Molex 39-30-1040

2 (-)

|

Simmer Sensor

| Simmer Sensor circuit is closed while simmer current flows through flashlamp and is open while simmer current is absent

3 (-)

|

Enable

| Once +5V voltage is applied to PIN3 integrated simmer supply tries to strike and maintain low-current discharge (simmer) in the flashlamp.

If flashlamp triggering is failed simmer supply module tries to trigger it again with a few Hertz repetition rate. After successful triggering the simmer supply can support up to 500mA flashlamp current (400mA is a preset by default).

Simmer will be maintained until 0V is applied to PIN3.

4 (-)| Enable Return| Return Simmer Enable signal

SIM CIRCUITS

LED

• There is the warning LED indicating that NBU-0808 circuits are under high voltage.
• HV LED (red) – is ON when NBU-0808 circuits are under high voltage

Warning! This equipment produces high voltages that can be very dangerous. Don’t be careless around this equipment.

• During operation all the protective covers of the equipment must be securely in place and all electrical connections must be properly attached
• NBU-0808 discharge circuit is designed to be installed inside a properly grounded metal. It is the user’s responsibility to ensure that personnel are prevented from accidentally contacting the NBU-0808, especially C+/C– , DR and L+/L– connectors and cables. Casual contact could be fatal!
• After shutdown, do not handle the capacitance load until it has been discharged. Use an appropriate meter to check for complete discharge.
• Disconnect the module from the DC power source before making or changing electrical or mechanical connections.
• Don’t remove protective covers! There are no user serviceable parts inside this equipment.

Operations

1. Connect capacitor charging power supply, +24V DC power supply, capacitor battery and flashlamp to NBU-0808 module

2. Set +5V voltage on PIN1 of PWF to switch off capacitor bank discharging Warning! By default capacitor discharging is on. Be careful and always switch off capacitor discharging before turning on your capacitor charging module. Otherwise, it may lead to failure of discharge resistors used in the system.

3. Disable simmer supply (PIN3 of SIM)

4. Apply +24V DC power to the module

5. Enable your capacitor charging power supply (charging module).
   As soon as charging module starts operation, capacitors are charged

6. Enable simmer supply (set +5V on PIN3 of SIM)

7. Wait a few seconds for Simmer Sensor. If it fails shut down your system

8. Disable your capacitor charging power supply before pulse Note that PCP-series and PCA-series power supplies by OEM Tech are well-protected and it isn’t obligatory to disable them. We recommend you do not disable PCP (PCA) at high on-off time ratio

9. Set +5V TTL pulse on PIN3 of PWF. This pulse duration defines IGBT-key open state time and flashlamp pulse width.

10. Enable your power supply after pulse

11. Repeat #8-#10

To power down NBU-0808 and discharge capacitor battery

1. Turn off or Disable your capacitor charging power supply (important!)
2. Disable simmer supply
3. Set 0V on PIN1 of PWF to switch on capacitor bank discharging. Wait for complete discharge of capacitors. Warning! If the capacitor bank capacitance is enormously high, this might lead to the overheating of the discharge resistors used in the system.
4. Remove +24V DC power from the module.

Specifications

ELECTRICAL

+24VDC:

Voltage| +24 V DC
Maximum current consumption| 5 A max, up to 10 A peak
PULSE PARAMETERS:
Max. voltage| 800 V (up to 1000V on request)
Max. discharge current (depends on flashlamp impedance K0)| 1000 A for pulse width < 1 ms

500 A for pulse width > 1 ms (other on request)

Max. average power| 2000 W (other on request)
Min. pulse width, max. pulse width| Accordingly to PWF:Pulse signal
Max. rep. rate| 100 Hz (up to 200Hz on request)
RECOMMENDED WIRES:
For capacitor bank connections| FLEXI-2V or similar (>1000V rated voltage,

4mm2 cross-section), short length (30cm recommended)

For flashlamp connections

| For external triggering – FLEXI-2V or similar (>1000V rated voltage, >4mm2 cross- section)

For serial triggering additional insulation (e.g. with silicone tubing) or spacing (e.g. with spiral bundle hose) of L– wire is required

SIMMER PARAMETERS
Simmer current| 400 mA ( 200-500 mA on request )
Max output voltage| 300 V
Max output power| 100 W
Open circuit voltage| 1500 V
FLASHLAMP TRIGGERING PARAMETERS
Trigger pulse width| ~1 us
Restrike rate| A few Hertz (automatically adjusted)
EXTERNAL:|
Pulse energy / trigger voltage| ~20mJ / 350V positive to the EXT connector ( other on request)

Trigger transformer

| External transformer (purchased separately) Recommended p/n ZS1324-24V LUL1(H) by Excelitas Technologies (Digikey p/n ZS1324- 24VLUL1(H)-ND )
---|---
SERIAL:|
Pulse energy / trigger voltage| ~160mJ / 10kV negative to L– ( other on request)
Trigger transformer| Integrated transformer
Cooling| Forced air cooling with built-in fan
Protections|
From overheating of internal components
Environment:|
Operation temperature| 0 … +40 °C
Storage temperature| -20 … +60 °C
Humidity| 90%, non-condensing

MECHANICAL

CABLE SET SUPPLIED WITH NBU-0808

DIMENSIONAL DRAWING

How to order? / Options
By default there is the only standard part number, namely NBU-0808.
On request the next options are available:

• Integrated current sensor
• High power / current / voltage IGBT with extended parameters
• Low power / current / voltage IGBT with reduced cost
• Digital RS-232 / RS-485 interface
• Modified cables and connectors
• Modified simmer and / or trigger parameters

Triggering. Serial triggering, external triggering, triggering basics
By default NBU-0808 supports both serial and external methods of triggering.

• To use NBU-0808 for external triggering, a trigger transformer should be connected to the EXT connector.
• Default parameters of external triggering are (other on request):
• 350V voltage (applied to EXT connector)
• ~20mJ energy
• Recommended transformer (sold separately) – 1:70 e.g. ZS1324-24V LUL1(H) by Excelitas Technologies (Digikey p/n ZS1324-24VLUL1(H)-ND)

If EXT connector is left unconnected, NBU-0808 automatically recognizes this and applies serial triggering to the flashlamp.

• Default parameters of serial triggering are (other on request):
• 10kV voltage (applied to L–)
• ~160mJ energy

References

• OEM Tech - Special power electronics for laser systems
• Discharge circuit forming pulses on a flashlamp and simmer current between them | OEM Tech

Read User Manual Online (PDF format)

Read User Manual Online (PDF format)  >>

Download This Manual (PDF format)

Download this manual  >>