Why Module Selection Deserves Care

The IGBT module is the most consequential component in a power converter. It sets the voltage class, the losses, the heatsink size and, in many cases, the reliability of the whole product. Choosing the wrong module late in a project costs time and money, which is why a structured selection process pays for itself. This guide walks through a repeatable method for selecting a MacMic IGBT module using the HN and 6TC series as the candidate set.

Step 1: Fix the Voltage Class

Start with the DC bus. A 380-480 V AC drive rectifies to roughly 560-680 V, and switching overshoot adds more, so a 1200 V module provides the necessary margin. Lower-voltage systems may use a 600 V class, while high-voltage or 690 V systems move to 1700 V. Never choose the voltage class from the nominal bus alone; include the switching overshoot you expect, because the device must survive the peak, not the average.

Overshoot and Margin

The commutation loop inductance and the switching speed set the overshoot. A module shrinks the loop compared with discretes, which reduces overshoot, but the DC-link layout and capacitor placement still matter. Leave at least fifteen percent margin between the worst-case peak and the module's blocking voltage, and measure overshoot at the module terminals during validation.

Step 2: Set the Current

Continuous current plus overload current sets the current rating. A motor drive may draw 150 percent of rated current for several seconds during acceleration, and welding equipment draws large repetitive pulses. Choose a module whose rated current covers the worst case at the expected case temperature, then verify junction temperature with the thermal path. Current ratings are specified at a case temperature, so a hot environment requires derating.

Switching Frequency

Switching frequency is the next filter. Below about 15 kHz, conduction loss dominates, so a low VCE(sat) device is efficient. Above 15 kHz, switching loss grows quickly and a high-speed module such as the HN series becomes attractive. Estimating both conduction and switching loss at the actual operating point is essential; the BeiLuo FAE team can run this comparison from the datasheets.

Step 3: Choose the Configuration

Circuit configuration reduces external parts. A half-bridge or three-phase bridge module covers most inverters, a single-switch suits choppers and large stages, and three-level modules support high-efficiency multi-level converters. Choosing a module that already contains the freewheeling diodes simplifies the design and improves the thermal coupling between the switch and its diode.

Step 4: Confirm the Thermal Design

Finally, confirm the thermal design. Start from the module's junction-to-case thermal resistance, add the interface and heatsink resistance, and verify junction temperature at worst-case current and ambient. A flat-substrate module gives consistent contact pressure and a predictable path. With genuine MacMic modules, documented compliance and FAE support from BeiLuo, you can move from selection to a reliable design quickly.

Documentation and Support

Every BeiLuo shipment of MacMic modules includes import declarations, certificates of origin and RoHS documents, and our FAE team supports gate drive, thermal design and layout review. Send your voltage, current, switching frequency and topology and we will propose a shortlist with measured recommendations and confirm stock and lead time for the parts you choose.