Field Oriented Control with (almost any?) Stepper

What feels like ages ago when we were both at the CBA, Sam Calisch pointed out to me that it’s possible to control a stepper motor as if it were a brushless motor, using field oriented control, aka FOC - everyone’s favourite motor control algorithm. This was an exciting idea and I quickly built a circuit to carry it out and I made a decent pass on the project back in 2021 although I never managed…