Parallel operation connects multiple power supplies with identical output voltages to increase the total available output current. The critical requirement is ensuring all power supplies maintain identical output voltages. While individual circuit currents may vary, the composite current It is expressed as:
where I1 to In represent the currents flowing through each individual circuit.
In parallel configurations, even minor voltage differences between power supplies can generate circulating currents. To achieve current balance, "equalizing resistors" are inserted at each power supply output. This approach proves particularly effective when connecting power supplies with varying characteristics, suppressing unwanted current flow due to voltage disparities, and ensuring proper current sharing among all units.
- Primary applications include:
- Electroplating: Multiple power supplies connected in parallel provide the substantial currents required, such as securing approximately 100 A output.
- Laser cluster drives: Applications demanding stable, high-current power delivery.
- Additional applications: These include semiconductor manufacturing equipment and medical devices, where power supply reliability and stability are paramount.
- Key considerations include:
- Current sharing circuits: Essential for preventing current imbalances between power supplies. Individual outputs are regulated through internal control systems or external circuitry.
- Cable resistance compensation: Prevents uneven current distribution caused by wiring resistance variations. Proper cable length and cross-sectional area design are crucial factors.
- These design measures enable safe and stable power delivery in parallel configurations, contributing to enhanced overall system reliability.