Prime mover load control on multi-speed generator set

A method of controlling a multi-speed generator set that is configured to power a transport climate control system while in transit, the multi-speed generator set including a controller and a prime mover coupled to a generator, the method comprising:

• the prime mover operating at a first non-zero speed;
• the controller monitoring a prime mover load parameter of the prime mover while the prime mover is operating at the first non-zero speed;
• the controller comparing the prime mover load parameter to an overload or stall threshold while the prime mover is operating at the first non-zero speed;
• the controller determining that the prime mover load parameter is greater than the overload or stall threshold indicating that a load demand on the prime mover is approaching or has exceeded a maximum load capacity of the prime mover at the first non-zero speed;
• and
• the prime mover switching from the first non-zero speed to a second non-zero speed that is lower than the first non-zero speed when the controller determines that the prime mover load parameter is greater than the overload or stall threshold to prevent an overload or stall situation.