DRIVE CONTROL DEVICE FOR DRIVE SYSTEM INCLUDING VERTICAL CARRIER MACHINE

• US 20150222207A1
• Filed: 08/27/2013
• Published: 08/06/2015
• Est. Priority Date: 09/11/2012
• Status: Active Grant

• Current Assignee: Nakanishi Metal Works Company Limited
• Original Assignee: Nakanishi Metal Works Company Limited
• Inventors: Matsushita, Katsumi
• Granted Patent: US 9,461,567 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B66B 1/302 for energy saving
• CPC Class Codes: B66B 1/308 with AC powered elevator drive
• CPC Class Codes: B66F 9/02 Stationary loaders or unloaders, e.g. for sacks
• CPC Class Codes: B66F 9/07 Floor-to-roof stacking devices, e.g. "stacker cranes", "retrievers"
• CPC Class Codes: B66F 9/24 Electrical devices or systems
• CPC Class Codes: H02P 27/06 using dc to ac converters or inverters H02P27/05 takes precedence
• CPC Class Codes: H02P 3/14 by regenerative braking
• CPC Class Codes: H02P 3/18 for stopping or slowing an ac motor
• CPC Class Codes: Y02B 50/00 Energy efficient technologies in elevators, escalators and moving walkways, e.g. energy saving or recuperation technologies

Abstract

An object of the present invention is to provide a drive control device for a drive system including a vertical carrier machine that makes effective use of regenerative power generated at a vertical carrier machine with a high proportion of regenerative operation. The drive control device for a drive system including a vertical carrier machine includes: a drive control device (A) for an electric motor (M1) mainly for regenerative operation; a drive control device (B) for an electric motor (M2) mainly for power operation; and a regenerative power storage capacitor (12) that is connected between a positive terminal (P11) and a negative terminal (N1) of a direct-current output line of a converter part (1) via a third inrush current suppression circuit (11) in which a third resistor (R3) and a switch (SW3) are connected in parallel, wherein the capacitor (12) has an electrostatic capacitance and a direct-current internal resistance to produce a current value with which braking torque required for velocity control of the electric motor (M1) mainly for regenerative operation is generated by a charging current flowing at storage of the regenerative energy generated by the electric motor (M1) mainly for regenerative operation, within an operating time during which maximum regenerative energy is generated, in series of operations by the electric motor (M1) mainly for regenerative operation.

Claims

1. A drive control device for a drive system including a vertical carrier machine, comprising:

a drive control device for an electric motor mainly for regenerative operation having a first inverter that is composed of a converter part that converts an alternating-current voltage supplied from an alternating-current primary power source into a direct-current voltage, a first smoothing circuit part that smoothes the direct-current voltage converted by the converter part, a first inrush current suppression circuit in which a first resistor and a first switch connected in parallel are connected to a primary side of the first smoothing circuit part, and a first inverter part that converts the direct-current voltage smoothed by the first smoothing circuit part into an alternating-current voltage at a variable voltage variable frequency and outputs the same to the electric motor mainly for regenerative operation in the vertical carrier machine, and a first inverter control part that controls the first inverter part to output the alternating-current voltage at a variable voltage variable frequency according to a velocity command;

a drive control device for an electric motor mainly for power operation having, between a positive terminal and a negative terminal of a direct-current output line of the converter part, a second inverter that is composed of a second smoothing circuit part that smoothes a direct-current voltage, a second inrush current suppression circuit in which a second resistor and a second switch connected in parallel are connected to a primary side of the second smoothing circuit part, a second inverter part that converts the direct-current voltage smoothed by the second smoothing circuit part into an alternating-current voltage at a variable voltage variable frequency and outputs the same to the electric motor mainly for power operation, and a second inverter control part that controls the second inverter part to output the alternating-current voltage at a variable voltage variable frequency according to a velocity command; and

a capacitor that is connected between the positive terminal and the negative terminal of the direct-current output line of the converter part via a third inrush current suppression circuit in which a third resistor and a third switch are connected in parallel, to store direct-current regenerative power generated at an input portion of the first inverter part during regenerative operation of the electric motor mainly for regenerative operation, wherein

the capacitor has an electrostatic capacitance (C) and a direct-current internal resistance (R) to produce a current value with which braking torque required for velocity control of the electric motor mainly for regenerative operation is generated by a charging current flowing at storage of the regenerative energy generated by the electric motor mainly for regenerative operation, within an operating time during which maximum regenerative energy is generated, in series of operations by the electric motor mainly for regenerative operation in the vertical carrier machine.

2. The drive control device for a drive system including a vertical carrier machine according to claim 1, wherein the capacitor has the electrostatic capacitance (C) in which an average charging current value (Ireg=C·

Δ

V/Ta) determined by dividing the product (C·

Δ

V) of the electrostatic capacitance (C) of the capacitor and a voltage increase value (Δ

V) caused by storing the regenerative energy in the capacitor by the operating time (Ta) is larger than a current value (Iave) that allows generation of braking torque necessary for velocity control of the electric motor mainly for regenerative operation (Iave<

Ireg), and has the direct-current internal resistance (R) in which a current value (I₀=Δ

V/R) determined by dividing the voltage increase value (Δ

V) by the direct-current internal resistance (R) of the capacitor is larger than the average charging current value (Ireg) (I₀>

Ireg).

3. The drive control device for a drive system including a vertical carrier machine according to claim 2, wherein the capacitor uses a calculation formula (e⁻

t/CR) for current residual rate at time (t) with a time constant (T=C·

R) determined by the product of the electrostatic capacitance (C) and the direct-current internal resistance (R) and the base (e) of natural logarithm to determine the residual rate of the current value (I₀) determined by dividing the voltage increase value (Δ

V) by the direct-current internal resistance (R) of the capacitor, and has the electrostatic capacitance (C) and the direct-current internal resistance (R) in which the time during which the residual rate is almost zero is shorter than the operating time (Ta).

4. The drive control device for a drive system including a vertical carrier machine according to claim 1,

wherein an on voltage of the transistor in the regenerative resistor circuit part connected in parallel to the first smoothing circuit part is lower than a withstand voltage of the capacitor.

5. The drive control device for a drive system including a vertical carrier machine according to claim 1, wherein an effective storable capacitance of the capacitor is equal to or larger than the sum of regenerative energy generated in one-cycle operation of the vertical carrier machine.

6. The drive control device for a drive system including a vertical carrier machine according to claim 1, wherein

the capacitor is connected directly to the positive terminal of the direct-current output line not via the third resistor but by the third switch that is turned on after the alternating-current primary power source is turned on and the capacitor is completely charged, and the positive terminal of the direct-current output line and the positive terminal of a direct-current bus of the first inverter are short-circuited, and at the same time, the first smoothing circuit part is charged through the first resistor, and after the charging of the first smoothing circuit part is completed, the first switch is turned on and the first inverter becomes operational, and

at the same time as the first inverter becomes operational, a fourth switch is turned on to connect the positive terminal of the direct-current bus of the first inverter and the positive terminal of the direct-current bus of the second inverter, and at the same time, the second smoothing circuit part is charged through the second resistor, and after the second smoothing circuit part is completely charged, the second switch is turned on and the second inverter becomes operational.

7. The drive control device for a drive system including a vertical carrier machine according to claim 1, wherein

the capacitor is connected directly to the positive terminal of the direct-current output line not via the third resistor but by the third switch that is turned on after the alternating-current primary power source is turned on and the capacitor is completely charged,

the first smoothing circuit part is charged through the first resistor in parallel to the charging of the capacitor, and after the charging of the first smoothing circuit part is completed, the first switch is turned on and the first inverter becomes operational, and

the second smoothing circuit part is charged through the second resistor in parallel to the charging of the capacitor and the first smoothing circuit part, and after the charging of the second smoothing circuit part is completed, the second switch is turned on and the second inverter becomes operational.

8. The drive control device for a drive system including a vertical carrier machine according to claim 1, wherein

the capacitor is connected directly to the positive terminal of the direct-current output line not via the third resistor but by the third switch that is turned on after the alternating-current primary power source is turned on and the capacitor is completely charged and a fifth switch that is connected in series to the third inrush current suppression circuit,

after the activation of the alternating-current primary power source, the first smoothing circuit part is charged through the first resistor, and after the charging of the first smoothing circuit part is completed, the first switch is turned on, and the second smoothing circuit part is charged through the second resistor in parallel to the charging of the first smoothing circuit part, and after the charging of the second smoothing circuit part is completed, the second switch is turned on, and

after the charging of the first smoothing circuit part and the second smoothing circuit part is completed, the fifth switch is turned on, and charging of the capacitor is started and the first inverter and the second inverter become operational.

9. The drive control device for a drive system including a vertical carrier machine according to claim 1, comprising a voltage measurement means for the capacitor, wherein

the capacitor is connected directly to the positive terminal of the direct-current output line not via the third resistor but by the third switch that is turned on after the alternating-current primary power source is turned on and the capacitor is completely charged and the fifth switch that is connected in series to the third inrush current suppression circuit,

after activation of the alternating-current primary power source, the first smoothing circuit part is charged through the first resistor, and after the charging of the first smoothing circuit part is completed, the first switch is turned on, and the second smoothing circuit part is charged through the second resistor in parallel to the charging of the first smoothing circuit part, and after the charging of the second smoothing circuit part is completed, the second switch is turned on, and

after the charging of the first smoothing circuit part and the second smoothing circuit part is completed, when the voltage value of the capacitor measured by the voltage measurement means is less than a preset threshold value, the fifth switch is turned on and charging of the capacitor is started, and the first inverter and the second inverter become operational, and after completion of the charging, when the voltage value of the capacitor measured by the voltage measurement means is equal to or larger than the preset threshold value, the fifth switch is turned on and the charging of the capacitor is completed, and the first inverter and the second inverter become operational.