MCF8316AEVM: Reverse Drive BLDC Motor Using MCF8316A

Hi Vuong,

Could you please save and upload your register settings JSON file using the GUI (File menu -> Save Registers) so I can take a look at your configurations?

When you change the direction, the motor will utilize reverse drive as shown here:

When the motor slows down in the reverse direction to a low speed, there won't be enough back-EMF generated to provide closed loop feedback. Therefore, the device has to switch to open loop commutation (a.k.a. blind commutation) to finish the final deceleration through zero speed, then accelerate in the forward direction, until enough forward back-EMF is generated to re-enter closed loop commutation.

During the open loop period, the device will use the open loop register configurations to determine the open loop current limit, acceleration rate, etc.

Regards,
Eric C.

Eric Chen said:

Therefore, the device has to switch to open loop commutation (a.k.a. blind commutation) to finish the final deceleration through zero speed,

Here is the current when very low speed and it made motor stopped and through zero speed. 

What is the current and how to create the current ? What process does the horizontal current represent?

Regards, 

Vuong N.T.

Eric Chen said:

Could you please save and upload your register settings JSON file using the GUI (File menu -> Save Registers) so I can take a look at your configurations?

Here is my JSON File

{
"signature": "oneui-register-data",
"data": [
[
{
"idx": 0,
"id": "isd_config",
"value": "0x7C630C0C"
},
{
"idx": 1,
"id": "rev_drive_config",
"value": "0x092AF064"
},
{
"idx": 2,
"id": "motor_startup1",
"value": "0x43A806D1"
},
{
"idx": 3,
"id": "motor_startup2",
"value": "0x181120B5"
},
{
"idx": 4,
"id": "closed_loop1",
"value": "0x020801B4"
},
{
"idx": 5,
"id": "closed_loop2",
"value": "0x6AF186BC"
},
{
"idx": 6,
"id": "closed_loop3",
"value": "0x6900A00A"
},
{
"idx": 7,
"id": "closed_loop4",
"value": "0x64F20096"
},
{
"idx": 8,
"id": "speed_profiles1",
"value": "0x00000000"
},
{
"idx": 9,
"id": "speed_profiles2",
"value": "0x00200000"
},
{
"idx": 10,
"id": "speed_profiles3",
"value": "0x00000000"
},
{
"idx": 11,
"id": "speed_profiles4",
"value": "0x00000000"
},
{
"idx": 12,
"id": "speed_profiles5",
"value": "0x00000000"
},
{
"idx": 13,
"id": "speed_profiles6",
"value": "0x00000000"
}
],
[
{
"idx": 0,
"id": "fault_config1",
"value": "0x4FE9024E"
},
{
"idx": 1,
"id": "fault_config2",
"value": "0x1001FF50"
}
],
[
{
"idx": 0,
"id": "pin_config",
"value": "0x00000000"
},
{
"idx": 1,
"id": "device_config1",
"value": "0x10100001"
},
{
"idx": 2,
"id": "device_config2",
"value": "0x0000B000"
},
{
"idx": 3,
"id": "peri_config1",
"value": "0x000C0000"
},
{
"idx": 4,
"id": "gd_config1",
"value": "0x0C010000"
},
{
"idx": 5,
"id": "gd_config2",
"value": "0x01000000"
}
],
[
{
"idx": 0,
"id": "ana_trim3",
"value": "0x48004800"
},
{
"idx": 1,
"id": "ana_trim4",
"value": "0x00000000"
},
{
"idx": 2,
"id": "ana_trim5",
"value": "0x00000009"
},
{
"idx": 3,
"id": "ana_trim6",
"value": "0x00000000"
},
{
"idx": 4,
"id": "ana_trim7",
"value": "0x00000000"
},
{
"idx": 5,
"id": "ana_trim8",
"value": "0x00004A43"
},
{
"idx": 6,
"id": "ana_trim9",
"value": "0x8095D820"
},
{
"idx": 7,
"id": "ana_trim10",
"value": "0xD3700138"
}
],
[
{
"idx": 0,
"id": "int_algo_1",
"value": "0x00B34278"
},
{
"idx": 1,
"id": "int_algo_2",
"value": "0x00000001"
}
],
[
{
"idx": 0,
"id": "gate_driver_fault_status",
"value": "0x00000000"
},
{
"idx": 1,
"id": "controller_fault_status",
"value": "0x00000000"
}
],
[
{
"idx": 0,
"id": "algo_status",
"value": "0x00000100"
},
{
"idx": 1,
"id": "mtr_params",
"value": "0x00000000"
},
{
"idx": 2,
"id": "algo_status_mpet",
"value": "0x00000000"
}
],
[
{
"idx": 0,
"id": "dev_ctrl",
"value": "0x00000000"
}
],
[
{
"idx": 0,
"id": "algo_ctrl1",
"value": "0x00000000"
},
{
"idx": 1,
"id": "algo_ctrl2",
"value": "0x00000000"
},
{
"idx": 2,
"id": "current_pi",
"value": "0x00099132"
},
{
"idx": 3,
"id": "speed_pi",
"value": "0x00000000"
},
{
"idx": 4,
"id": "dac_1",
"value": "0x00000000"
},
{
"idx": 5,
"id": "dac_2",
"value": "0x00000000"
}
],
[
{
"idx": 0,
"id": "algorithm_state",
"value": "0x00000000"
},
{
"idx": 1,
"id": "fg_speed_fdbk",
"value": "0x7FFFFFFF"
},
{
"idx": 2,
"id": "bus_current",
"value": "0x00000000"
},
{
"idx": 3,
"id": "phase_current_a",
"value": "0x00000000"
},
{
"idx": 4,
"id": "phase_current_b",
"value": "0x00000000"
},
{
"idx": 5,
"id": "phase_current_c",
"value": "0x00000000"
},
{
"idx": 6,
"id": "csa_gain_feedback",
"value": "0x00010003"
},
{
"idx": 7,
"id": "voltage_gain_feedback",
"value": "0x00000001"
},
{
"idx": 8,
"id": "vm_voltage",
"value": "0x033FC000"
},
{
"idx": 9,
"id": "phase_voltage_va",
"value": "0x00000000"
},
{
"idx": 10,
"id": "phase_voltage_vb",
"value": "0x00000000"
},
{
"idx": 11,
"id": "phase_voltage_vc",
"value": "0x00000000"
},
{
"idx": 12,
"id": "sin_commutation_angle",
"value": "0x00000000"
},
{
"idx": 13,
"id": "cos_commutation_angle",
"value": "0x00000000"
},
{
"idx": 14,
"id": "ialpha",
"value": "0x00000000"
},
{
"idx": 15,
"id": "ibeta",
"value": "0x00000000"
},
{
"idx": 16,
"id": "valpha",
"value": "0x00000000"
},
{
"idx": 17,
"id": "vbeta",
"value": "0x00000000"
},
{
"idx": 18,
"id": "id",
"value": "0x00000000"
},
{
"idx": 19,
"id": "iq",
"value": "0x00000000"
},
{
"idx": 20,
"id": "vd",
"value": "0x00000000"
},
{
"idx": 21,
"id": "vq",
"value": "0x00000000"
},
{
"idx": 22,
"id": "iq_ref_rotor_align",
"value": "0x00000000"
},
{
"idx": 23,
"id": "speed_ref_open_loop",
"value": "0x00000000"
},
{
"idx": 24,
"id": "iq_ref_open_loop",
"value": "0x00000000"
},
{
"idx": 25,
"id": "speed_ref_closed_loop",
"value": "0x00000000"
},
{
"idx": 26,
"id": "id_ref_closed_loop",
"value": "0x00000000"
},
{
"idx": 27,
"id": "iq_ref_closed_loop",
"value": "0x00000000"
},
{
"idx": 28,
"id": "isd_state",
"value": "0x00000000"
},
{
"idx": 29,
"id": "isd_speed",
"value": "0x00000000"
},
{
"idx": 30,
"id": "ipd_state",
"value": "0x00000000"
},
{
"idx": 31,
"id": "ipd_angle",
"value": "0x00000000"
},
{
"idx": 32,
"id": "ed",
"value": "0x00000000"
},
{
"idx": 33,
"id": "eq",
"value": "0x00000000"
},
{
"idx": 34,
"id": "speed_fdbk",
"value": "0x00000000"
},
{
"idx": 35,
"id": "theta_est",
"value": "0x00000000"
}
]
]
}

Hi Vuong,

Please let me review your register settings and I'll get back to you tomorrow.

Thanks,

Eric C.