Bee Technologies provide Concept Kit of Unipolar Drive Circuit Simulation using PSpice.
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All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 1
B
Bcom
A
/B
Acom
/A
U1UNI-POLAR_STEP_MOTRL = 2.5MR = 4.2
U8
AND
U9
AND
R1
1k
0
FB
DIODED1
DIODED2
DIODED3
DIODED4
PARAMETERS:
I_SET = 0.5
VHYS = 0.1
B
0
PARAMETERS:
RON = 10m
0
U101-PHASEPPS = 100
CLK
FA
/FA
FB
/FB
0
0
U6
AND
FA
+
-
REF
-+
FB.
U2
HYS_I-CTRL
I_SET = {I_SET}VHYS = {VHYS}
/FA
/FB
VCC
+
-
REF
-+
FB.
U3
HYS_I-CTRL
I_SET = {I_SET}VHYS = {VHYS}
+
-
REF
-+
FB.
U4
HYS_I-CTRL
I_SET = {I_SET}VHYS = {VHYS}
/B
/A
+
-
+
-
S4
SRON = {RON}
A
+
-
REF
-+
FB.
U5
HYS_I-CTRL
I_SET = {I_SET}VHYS = {VHYS}
CLK
+
-
+
-
S1
SRON = {RON}
+
-
+
-
S2
SRON = {RON}
+
-
+
-
S3
SRON = {RON}
VCC
VCC VCC
0
VCC
Vcc
12
VCC
VCC
U7
AND
Unipolar Stepping Motor Drive Circuit Simulation
PSpice Version
Unipolar Stepping Motor Drive Circuit
Contents
1. Concept of Simulation
2. Unipolar Stepping Motor Drive Circuit
3. Unipolar Stepping Motor
4. Switches
5. Signal Generator
6. Hysteresis-Based Current Controller
7. Unipolar Stepping Motor Drive Circuit (Example)
All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 2
All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 3
Driver Unit:(e.g. Hysteresis-
Based Controller)
Parameter:
• I_SET
• HYS
Switches(e.g. FET,
Diode)
Parameter:
• Ron
Stepping
Motor
Parameter:
• L
• R
Control Unit (e.g. Microcontroller)
Sequence:
• One-Phase
• Two-Phase
• Half-Step
U?1-PHASEPPS = 100
CLK
FA
/FA
FB
/FB
U?2-PHASEPPS = 100
CLK
FA
/FA
FB
/FB
U?HALF-STEPPPS = 100
CLK
FA
/FA
FB
/FB
B
Bcom
A
/B
Acom
/A
U?UNI-POLAR_STEP_MOTRL = 2.5MR = 4.2
Models:
Block Diagram:
DIODED1
0
+
-
+
-
S1
SRON = 10m
VCC
Ctrl_A A
1.Concept of Simulation
U2
AND
+
-
REF
-+
FB.
U1
HYS_I-CTRL
I_SET = {I_SET}VHYS = {VHYS}
Ctrl_AFA
2.Unipolar Stepping Motor Drive Circuit
All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 4
Signal generator Hysteresis Based Current
Controller
Switches Unipolar Stepping Motor Supply Voltage
B
Bcom
A
/B
Acom
/A
U1UNI-POLAR_STEP_MOTRL = 2.5MR = 4.2
U8
AND
U9
AND
R1
1k
0
FB
DIODED1
DIODED2
DIODED3
DIODED4
PARAMETERS:
I_SET = 0.5
VHYS = 0.1
B
0
PARAMETERS:
RON = 10m
0
U101-PHASEPPS = 100
CLK
FA
/FA
FB
/FB
0
0
U6
AND
FA
+
-
REF
-+
FB.
U2
HYS_I-CTRL
I_SET = {I_SET}VHYS = {VHYS}
/FA
/FB
VCC
+
-
REF
-+
FB.
U3
HYS_I-CTRL
I_SET = {I_SET}VHYS = {VHYS}
+
-
REF
-+
FB.
U4
HYS_I-CTRL
I_SET = {I_SET}VHYS = {VHYS}
/B
/A
+
-
+
-
S4
SRON = {RON}
A
+
-
REF
-+
FB.
U5
HYS_I-CTRL
I_SET = {I_SET}VHYS = {VHYS}
CLK
+
-
+
-
S1
SRON = {RON}
+
-
+
-
S2
SRON = {RON}
+
-
+
-
S3
SRON = {RON}
VCC
VCC VCC
0
VCC
Vcc
12
VCC
VCC
U7
AND
3.Unipolar Stepping Motor
All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 5
• The electrical equivalent circuit of each phase consists
of an inductance of the phase winding series with
resistance.
• The inductance is ideal (without saturation
characteristics and the mutual inductance between
phases)
• The motor back EMF is set as zero to simplified the
model parameters extraction.
B
Bcom
A
/B
Acom
/A
U1UNI-POLAR_STEP_MOTRL = 2.5MR = 4.2
Input the inductance and resistance values (parameter: L, R) of the stepping motor, that are usually provided by the manufacturer datasheet, to generally model the phase winding.
4.Switches
All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 6
• A near-ideal DIODE can be modeled by using spice
primitive model (D), which parameter: N=0.01
RS=0.
• A near-ideal MOSFET can be modeled by using
PSpice VSWITCH that is voltage controlled switch.
DIODED1
0
+
-
+
-
S1
SRON = 10m
VCC
Ctrl_A A
The parameter RON represents Rds(on) characteristics of MOSFET, that are usually provide by the manufacturer datasheet. The value could be about 10m to 10 ohm.
5.Signal Generator
The signal generators are used as a microcontroller capable of generating step pulses
and direction signals for the driver.
There are 3 useful stepping sequences to control unipolar stepping motor
All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 7
One-Phase (Wave Drive)
• Consumes the least power.
• Assures the accuracy regardless of the winding imbalance.
Two-Phase (Hi-Torque)
• Energizes 2 phases at the same time.
• Offers an improved torque-speed result and greater holding torque.U?1-PHASEPPS = 100
CLK
FA
/FA
FB
/FB
U?2-PHASEPPS = 100
CLK
FA
/FA
FB
/FB
U?HALF-STEPPPS = 100
CLK
FA
/FA
FB
/FB
Half-Step
• Doubles the stepping resolution of the motor.
• Reduces motor resonance which could cause a motor to stall at a resonant frequency.
• Please note that this sequence is 8 steps.
Input PPS (Pulse Per Second) as a clock pulse speed(frequency).
5.1 One-Phase Sequence
All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 8
Time
0s 40ms 80ms
V(/FB)
0V
5.0V
SEL>>
V(FB)
0V
2.5V
5.0V
V(/FA)
0V
2.5V
5.0V
V(FA)
0V
2.5V
5.0V
V(CLK)
0V
2.5V
5.0V
ON
ON
ON
ON
Clock
Phase A
Phase /A
Phase B
Phase /B
1 Sequence
Time
0s 40ms 80ms
V(/FB)
0V
5.0V
SEL>>
V(FB)
0V
2.5V
5.0V
V(/FA)
0V
2.5V
5.0V
V(FA)
0V
2.5V
5.0V
V(CLK)
0V
2.5V
5.0V
5.2 Two-Phase Sequence
All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 9
ON
ON
ON
ON
1 Sequence
Clock
Phase A
Phase /A
Phase B
Phase /BON
Time
0s 80ms 160ms
V(/FB)
0V
5.0V
SEL>>
V(FB)
0V
2.5V
5.0V
V(/FA)
0V
2.5V
5.0V
V(FA)
0V
2.5V
5.0V
V(CLK)
0V
2.0V
4.0V
5.3 Half-Step Sequence
All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 10
ON
ON
ON
1 Sequence
Clock
Phase A
Phase /A
Phase B
Phase /BON
6.Hysteresis-Based Current Controller
All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 11
• Controlled by the signal from the
microcontroller.
• Generate the switch (MOSFET) drive signal
by comparing the measured phase current
with their references.
Input the reference value at the I_SET (e.g. I_SET=0.5A) to set the regulated current level. The hysteresis current value is set at the VHYS (e.g. VHYS=0.1A).