While lower frequencies are acceptable, the specified levels are at the point where conduction losses strongly dominate over switching losses. Efficiency gains for operating slower would be minimal, and audible noise would likely become more objectionable. Low switching frequencies are typically employed in motor drive applications, where the motor’s inductance provides sufficient filtering without additional size or cost. In inverter and DC/DC applications, OZIP IPM power savings needs to be balanced against increased filter inductor power loss, size and cost when considering a low switching frequency. Higher frequency operation is limited by both power stage switching loss and IGBT gate driver capacity. Generally, models with smaller IGBTs can safely switch faster, and will have a proportionally smaller switching to conduction loss ratio, as reflected in the current capability plots. The specified max operating frequencies are practical maximums that result in reasonable power stage switching losses and safe utilization of gate driver capability. Contact the factory for applications that may require higher than specified switching frequencies.