SJ700-2 Instruction Manual NT204DX - Hitachi America, Ltd.
SJ700-2 Instruction Manual NT204DX - Hitachi America, Ltd.
SJ700-2 Instruction Manual NT204DX - Hitachi America, Ltd.
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Chapter 4 Explanation of Functions<br />
4.2.97 Sensorless vector, 0 Hz domain control<br />
The 0Hz domain sensorless vector (SLV) control function<br />
incorporates <strong>Hitachi</strong>’s own torque control system and<br />
enables high-torque operation in the 0Hz range (0 to 3 Hz).<br />
This control function is best suited for driving a lifting machine,<br />
e.g., crane or hoist, that requires sufficient torque when<br />
starting at a low frequency.<br />
To use this function, specify "04" for the V/F characteristic<br />
curve selection (A044/A244).<br />
Before using this function, be sure to optimize constant<br />
settings for the motor with reference to Section 4.2.91, "Motor<br />
constant selection."<br />
The parameters related to the 0Hz-range sensorless vector<br />
control are as follows:<br />
1) The Zero LV lmit for 1st/2nd motors (H060/H260) is the<br />
parameter that specifies the output current for the<br />
constant-current control in the 0 Hz range (about 3.0 Hz or<br />
less). The parameter value is expressed as a ratio of the<br />
output current to the inverter's rated current.<br />
2) The Zero LV starting boost current (H061/H261) is the parameter to specify the current for boosting at<br />
motor start-up with a frequency in the 0 Hz range. The parameter value is expressed as a ratio of the boost<br />
current to the inverter's rated current. The value of the boost current is added to the current value specified<br />
by "H060/H260" only at starting.<br />
Item Function code Range of data Description<br />
Zero LV lmit H060/H260 0.0 to 100.0 (%) Current limiter for the low-speed range<br />
Zero LV starting boost current H061/H261 0. to 50. (%) Quantity of boost current at starting<br />
When using this function, observe the following precautions:<br />
1) Be sure to use an inverter of which the capacity is one class higher than the motor to be driven.<br />
2) If you use the inverter to drive a motor of which the capacity is two classes lower than the maximum<br />
applicable capacity of the inverter, you may not be able to obtain adequate motor characteristics.<br />
3) If you cannot obtain desired characteristics from the motor driven under the 0Hz-range sensorless<br />
vector control, readjust the motor constants according to the symptom as described in the table below.<br />
Operation<br />
Symptom Adjustment method Adjustment item<br />
status<br />
Momentary speed Increase the motor constant R2 step by step from the<br />
H021/H221/H031<br />
Powering<br />
Regenerating<br />
Starting<br />
Decelerating<br />
Immediately<br />
after<br />
deceleration<br />
Low-frequency<br />
operation<br />
variation is negative.<br />
Momentary speed<br />
variation is positive.<br />
Torque is insufficient at<br />
low frequencies<br />
(several Hz)<br />
set value up to 1.2 times as high as the set value.<br />
Reduce the motor constant R2 step by step from the set<br />
H021/H221/H031<br />
value down to 0.8 times as high as the set value.<br />
Increase the motor constant R1 step by step from the<br />
H020/H220/H030<br />
set value up to 1.2 times as high as the set value.<br />
Increase the motor constant I0 step by step from the set<br />
H023/H223/H033<br />
value up to 1.2 times as high as the set value.<br />
The motor generates an<br />
Reduce the motor constant J from the set value.<br />
impact when it starts.<br />
H024/H224/H034<br />
The motor runs Reduce the speed response setting.<br />
H005/H205<br />
unsteadily. Reduce the motor constant J from the set value. H024/H224/H034<br />
Reduce the motor constant I0 step by step from the set<br />
Overcurrent or<br />
H023/H223/H033<br />
value down to 0.8 times as high as the set value.<br />
overvoltage protection<br />
function operates.<br />
A081<br />
Motor rotation is<br />
inconsistent.<br />
Specify "00" (always on) or "01" (always off) for the AVR<br />
function select (A081).<br />
Increase the motor constant J from the set value.<br />
Related code<br />
A001: Frequency source setting<br />
A044/A244: V/F characteristic curve selection,<br />
1st/2nd motors<br />
F001: Output frequency setting<br />
b040: Torque limit selection<br />
b041 to b044: Torque limit (1) to (4)<br />
H002/H202: Motor data selection, 1st/2nd motors<br />
H003/H203: Motor capacity, 1st/2nd motors<br />
H004/H204: Motor poles setting, 1st/2nd motors<br />
H005/H205: Motor speed constant, 1st/2nd motors<br />
H020/H220: Motor constant R1, 1st/2nd motors<br />
H021/H221: Motor constant R2, 1st/2nd motors<br />
H022/H222: Motor constant L, 1st/2nd motors<br />
H023/H223: Motor constant Io, 1st/2nd motors<br />
H024/H224: Motor constant J, 1st/2nd motors<br />
H050/H250: PI proportional gain, 1st/2nd motors<br />
H051/H251: PI integral gain, 1st/2nd motors<br />
H052/H252: P proportional gain setting, 1st/2nd<br />
motors<br />
H060/H260: Zero LV lmit, 1st/2nd motors<br />
H061/H261: Zero LV starting boost current, 1st/2nd<br />
motors<br />
H024/H224/H034<br />
Note 1: Always set the carrier frequency (b083) to 2.1 kHz or more. If the carrier frequency is less than 2.1<br />
kHz, the inverter cannot operate the motor normally.<br />
Note 2: Adjust the torque limit (b041 to b044) so that the value "α" calculated by the expression below<br />
does not exceed 200%. Otherwise, the motor may be burnt out.<br />
α = "torque limit" x (inverter capacity)/(motor capacity)<br />
(Example) When the inverter capacity is 0.75 kW and the motor capacity is 0.4 kW, the torque limit<br />
value is calculated as follows on the assumption that the value "α" should be 200%:<br />
Torque limit (b041 to b044) = α x (motor capacity)/(inverter capacity) = 200% x (0.4<br />
kW)/(0.75 kW) = 106%<br />
4 - 91
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