Set point control for fixed speed engine driven fracking pumps

A system for injecting fracking fluid into a wellbore, comprising:

• first fracking pumps each comprising a fixed speed engine driven power train;
• second fracking pumps each comprising a variable speed engine driven power train;
• and
• a controller configured to:
• determine a combination of first flow rate setpoints of the first fracking pumps corresponding to gears of the first fracking pumps and a combination of second flow rate setpoints of the second fracking pumps such that a sum of the first flow rate setpoints plus a sum of the second flow rate setpoints meets a desired total flow rate of the first fracking pumps and the second fracking pumps;
• and
• transmit the first flow rate setpoints to the first fracking pumps, and transmit the second flow rate setpoints to the second fracking pumps,
• wherein the first fracking pumps are configured to inject fracking fluid into the wellbore according to the first pump rate setpoints, and the second fracking pumps are configured to inject fracking fluid into the wellbore according to the second pump rate setpoints.

A method for injecting fracking fluid into a wellbore, comprising:

• determining, by a controller, a combination of flow rate setpoints of fracking pumps corresponding to gears of the fracking pumps such that a sum of the flow rate setpoints meets a desired total flow rate of the fracking pumps;
• transmitting, by the controller, the flow rate setpoints to the fracking pumps;
• and
• injecting, by the fracking pumps, fracking fluid into the wellbore according to the pump rate setpoints,
• wherein the fracking pumps each comprising a fixed speed engine driven power train.