Hitachi SJ700-2 instruction manual Sensorless vector control, H021/H221/H031

Related code A001: Frequency source setting

A044/A244: V/F characteristic curve selection, 1st/2nd motors

F001: Output frequency setting

b040: Torque limit selection

b041 to b044: Torque limits (1) to (4)

H002/H202: Motor data selection, 1st/2nd motors

H003/H203: Motor capacity, 1st/2nd motors

H004/H204: Motor poles setting, 1st/2nd motors

H005/H205: Motor speed constant, 1st/2nd motors

H020/H220: Motor constant R1, 1st/2nd motors

H021/H221: Motor constant R2, 1st/2nd motors

H022/H222: Motor constant L, 1st/2nd motors

H023/H223: Motor constant Io, 1st/2nd motors

H024/H224: Motor constant J, 1st/2nd motors

H050/H250: PI proportional gain, 1st/2nd motors

H051/H251: PI integral gain, 1st/2nd motors

H052/H252: P proportional gain setting, 1st/2nd motors

Chapter 4 Explanation of Functions

4.2.96 Sensorless vector control

The sensorless vector control function estimates and controls the motor speed and output torque on the basis of the inverter output voltage and output current and the motor constants set on the inverter. This function enables the inverter to accurately operate the motor with a high starting torque, even at a low frequency (0.3 Hz or more).

To use this function, specify "03" for the V/F characteristic curve selection (A044/A244).

Before using this function, be sure to make optimum constant settings for the motor with reference to Section 4.2.91, "Motor constant selection."

When using this function, observe the following precautions:

1) If you use the inverter to drive a motor of which the capacity is two classes lower than the maximum applicable capacity of the inverter, you may not be able to obtain adequate motor characteristics.

2)If you cannot obtain the desired characteristics from the motor driven under the sensorless vector control, readjust the motor constants according to the symptom, as described in the table below.

Operation	Symptom	Adjustment method	Adjustment item
status
	Momentary speed	Increase the motor constant R2 step by step from the	H021/H221/H031
Powering	variation is negative.	set value up to 1.2 times as high as the set value.
	Momentary speed	Reduce the motor constant R2 step by step from the set	H021/H221/H031
	variation is positive.	value down to 0.8 times as high as the set value.
	Torque is insufficient at	Increase the motor constant R1 step by step from the	H020/H220/H030
Regenerating	low frequencies	set value up to 1.2 times as high as the set value.
		Increase the motor constant Io step by step from the set
	(several Hz)		H023/H223/H033
		value up to 1.2 times as high as the set value.
Starting	The motor generates an	Reduce the motor constant J from the set value.	H024/H224/H034
	impact when it starts.
Decelerating	The motor runs	Reduce the speed response setting.	H005/H205
	unsteadily.	Reduce the motor constant J from the set value.	H024/H224/H034
	Torque is insufficient
Torque-limited	during torque-limited	Reduce the overload restriction level to lower than the	b021, b041 to b044
operation	operation at a low	torque limiter level.
	frequency.
Low-frequency	Motor rotation is	Increase the motor constant J from the set value.	H024/H224/H034
operation	inconsistent.
starting	Motor runs backwards	Set 01 (enable) on reverse run protection function	b046
	for short moment.	(b046)

Note 1: Always set the carrier frequency (b083) to 2.1 kHz or more. If the carrier frequency is less than 2.1 kHz, the inverter cannot operate the motor normally.

Note 2: When driving a motor of which the capacity is one class lower than the inverter, adjust the torque limit (b041 to b044) so that the value "α" calculated by the expression below does not exceed 200%. Otherwise, the motor may be burnt out.

α= "torque limit" x (inverter capacity)/(motor capacity)

(Example) When the inverter capacity is 0.75 kW and the motor capacity is 0.4 kW, the torque limit value is calculated as follows, based on the assumption that the value "α" should be 200%:

Torque limit (b041 to b044) = α x (motor capacity)/(inverter capacity) = 200% x (0.4 kW)/(0.75 kW) = 106%

4 - 89