For this week’s QSPICE schematic capture, we have one by Qorvo’s Lei Han, “Motor 3 Phase.” This schematics capture showcases a complete 3-phase BLDC motor drive system modeled in QSPICE, featuring bi-directional control of BLDC motor drive using 6-step commutation control scheme with speed-loop and ideal rotor position/speed feedback. The model includes the support of advance angle adjustment to optimize efficiency. The motor model supports customized Back Electromotive Force (BEMF) shaping using harmonics synthesis. The digital control blocks mimic typical timing of ISR based FW implementation in an MCU. This simulation work is based on parameters of a real BLDC motor and using SPICE device models for the inverter power stage instead of ideal models. The simulation speed is reasonably fast (about 5 min. for 1 sec. transient analysis). The result reveals that:
- Phase current peaks up to more than 2 times of the steady-state level during start-up
- Negative Te is requested by speed PI to break the motor upon speed reference step change (3000 RPM to 0 RPM)
This work demonstrates how QSPICE can be used to simulate not only device-level switching dynamics but also embedded motor-control algorithms within a single environment.
Please send any submissions to me at tim.mccune@qorvo.com (Schematic Capture Post #085)
hbgd_bbm_dt_v1.dll (20.0 KB)
HBGD_BST_V1.qsch (18.1 KB)
motor-3ph 6-step control base-line w. bi-directional speed loop+GD.qsch (61.7 KB)
motor-3ph_V2.6.qsch (20.3 KB)
Sixstep_comm_V2.dll (33.0 KB)
bemf_gen.dll (33.0 KB)
digital_pi_v1.dll (20.0 KB)
digital_pwm_modulator_v1.dll (33.5 KB)
