JPH04297A - Controller for crane - Google Patents

Abstract

PURPOSE:To utilize regenerative electric power, produced in a crane motor, effectively by a method wherein the title controller is provided with a flywheel controlling inverter for controlling a flywheel motor and a regenerative control unit outputting a commanding signal based on a DC voltage for a crane motor controlling inverter. CONSTITUTION:A flywheel controlling inverter 16 for controlling a flywheel motor IM3 and a regenerative control unit 17 are provided as a means for absorbing and accumulating regenerative electric power generated by crane motors IM1, IM2. When a regenerative control unit 17 detects the increase of a DC voltage for crane motor controlling inverters 13, 14, the regenerative control unit 17 outputs a commanding signal to the flywheel controlling inverter 16 so as to increase the rotating speed of the flywheel motor IM3. A regenerative electric power, corresponding to the increased amount of the rotating speed of the flywheel motor IM3, is converted into the form of an inertia energy and is accumulated. According to this method, the increase of a DC voltage in the input side of the crane motor controlling inverter 16 can be restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a crane control device of a type that controls a crane motor by inverter control.

In particular, the present invention relates to a control device for effectively utilizing regenerated power generated when lowering a suspended load.

(Prior art) In a type of crane that controls the crane motor using inverter control, when lowering a suspended load, the crane motor often rotates at a speed higher than necessary due to the suspended load, generating regenerative power. happen. This regenerated power causes an increase in DC voltage to the inverter. Namely.

The input side of the inverter is equipped with a circuit that rectifies alternating current into direct current and a circuit that smoothes the output of this rectifying circuit, and when regenerative power is generated, the voltage of the smoothing circuit increases. For this reason, conventional cranes of this type take measures to consume the generated regenerative power. For example, a first method uses a converter with a regeneration function, and in this method, power is regenerated each time regenerated power is generated.

Furthermore, as a second method, there is a method in which a power consumption resistor is connected to the smoothing circuit via a switch. This second
In this method, when the voltage of the smoothing circuit increases due to the regenerated power, the switch is turned on and a resistor is connected to the smoothing circuit.

The regenerated power is consumed by the resistor.

(Problems to be Solved by the Invention) However, although regenerative power can be used effectively in the first method, the regenerated power is used only when regenerated power is being generated.

Furthermore, in the second method, the once-regenerated power is only converted into thermal energy and released, and is not used effectively.

In addition, in a crane equipped with an engine generator or the like as a power source, power regeneration is impossible, and there is a problem in that the above-mentioned second method has to be adopted.

In view of the above-mentioned problems, the main object of the present invention is to provide a crane control device that can effectively utilize regenerated electric power.

Another object of the present invention is to provide a crane control device that can achieve the above object while accumulating regenerated power.

(Means for Solving the Problems) According to the present invention, 2. As a means for absorbing and accumulating regenerative power generated by a crane motor, the flywheel device is connected in parallel with a flywheel device and the inverter for controlling the crane motor; A crane comprising: a flywheel control inverter for controlling a flywheel motor in a wheel device; and a regeneration control section that sends a command signal based on a DC voltage to the crane motor control inverter. A control device is obtained.

Also according to the invention. As a means for supplying DC voltage to the inverter for controlling the crane motor.

The regeneration control section includes means for rectifying a power supply voltage and a circuit for smoothing the rectified voltage, and the regeneration control section includes a means for detecting the voltage of the smoothing circuit, and a detection value and a set value by the voltage detection means. There is obtained a crane control device characterized in that it includes arithmetic means for transmitting a frequency command value for increasing speed to the flywheel control inverter as the command signal based on the above-described method. According to the present invention, the regeneration control section further includes means for detecting the input power to the rectifying means, and the calculation means is configured to combine the signal from the input power detecting means with the input power for controlling the flywheel. There is obtained a crane control device characterized in that a frequency command value for deceleration is sent to the flywheel control inverter as the command signal based on a frequency feedback signal from the flywheel control inverter.

(Function) The present invention focuses on the fact that when regenerated power is generated in the crane motor, this regenerated power passes through the crane motor control inverter and increases the DC voltage on the input side. When detecting an increase in the flywheel motor, a command signal is sent to the flywheel control inverter to increase the rotational speed of the flywheel motor. The rotational speed of the flywheel motor increases.

This means that the regenerated power has been converted into inertial energy and stored by the amount of increase, and this suppresses an increase in the DC voltage on the input side of the crane motor control inverter.

On the other hand, when the calculation means determines that the input power exceeds the reference power calculated by frequency feedback from the wheel motor control inverter, the calculation means decelerates the flywheel motor by regenerative braking. Sends a command signal.

At this time, the regenerated power of the flywheel motor is returned to the input side of the crane motor control inverter.

(Example) An example of the present invention will be described below with reference to FIG.

In FIG. 1, a rectifier 11 is connected to a power source (not shown) by an engine generator. DC voltage is supplied to the two crane motor control inverters 13 and 14 through the smoothing circuit 12. Crane motor control inverter 13.14
are connected in parallel to the smoothing circuit 12, and each output has a crane motor IM1. IM2 is connected.

Crane motor! M1. Or as a configuration for absorbing and accumulating 1M2 of generated regenerative power.

A flywheel device including a flywheel motor IM and a flywheel 15, and a wheel motor control inverter 16 for controlling the flywheel device.

A regeneration control section 17 is provided for sending out a command signal. The wheel motor control inverter 16 is connected to the crane motor control inverter 1 with respect to the smoothing circuit 12.
Connected in parallel with 3.14.

The regeneration control unit 17 includes a CT (current transformer) 20 provided on the input side of the rectifier 11. The input power is calculated based on the detection signal of the PT (power transformer) 21.

and a power detection circuit 22 that converts this into a voltage signal.

It consists of a voltage detection circuit 23 that detects the DC voltage of the smoothing circuit 12, and a calculation section 24 that sends a frequency command signal to the wheel motor control inverter 16 based on detection signals from these two detection circuits. The calculation unit 24 compares the detection signal from the power detection circuit 22, that is, the input power, with the reference power, and when the input power exceeds the reference power, the calculation unit 24 issues a frequency command value for deceleration to the wheel motor control inverter 16. Output. Note that the reference power is calculated by the calculation unit 24 based on the frequency feedback signal from the wheel motor control inverter 16. Further, the calculation unit 24 compares the detection signal from the voltage detection circuit 23, that is, the DC voltage and the reference voltage, and when the DC voltage exceeds the reference voltage, the calculation unit 24 transmits a frequency to the wheel motor control inverter 16 to increase the speed. Outputs the command value. The reference voltage is set in advance.

Here, to simplify the explanation, we will use the crane motor IM
, is being driven.

The flywheel equipment is also in operation while the crane is in use. The crane motor IM is activated by lowering the suspended load.
When a negative load, that is, regenerated power is generated on the motor 1, the regenerated power is returned to the smoothing circuit 12 through the crane motor control inverter 13.

This regenerated power is accumulated in the capacitor of the smoothing circuit 12, thereby increasing the DC voltage of the smoothing circuit 12.

This DC voltage value is passed through the voltage detection circuit 23 to the arithmetic unit 24.
sent to.

The arithmetic unit 24 determines that regenerative power has been generated when the DC voltage value from the voltage detection circuit 23 becomes higher than a predetermined set value (the power supply voltage value may be sufficient), and measures the increase in DC voltage accordingly. The frequency command value increased by that value is output to the wheel motor control inverter 16.

The wheel motor control inverter 16 controls the input frequency value, in other words, the regenerative power only for the wheel motor IM.
, a wheel motor IM to increase the rotational speed of ,
control. As a result, in the flywheel device, inertial energy increases by the amount of regenerated power generated by the crane motor IM. This increase in inertial energy means that the regenerated power generated by the crane motor IM1 is absorbed and stored in the flywheel device.

As a result, an increase in the DC voltage in the smoothing circuit 12 is immediately suppressed.

Note that the inertial energy accumulated in the flywheel device is returned to the smoothing circuit 12 side through the wheel motor control inverter 16 under conditions described later. That is, the calculation unit 24 calculates the base r$ and power based on the frequency feedback from the wheel motor control inverter 16, and when the input power detected by the power detection circuit 22 exceeds this reference power, the calculation unit 24 calculates the power by the amount that exceeds the reference power. A reduced frequency command value is output so as to reduce the rotational speed of the wheel motor IM.

The wheel motor control inverter 16 decelerates the flywheel device by regenerative braking based on the input frequency command value, and the resulting regenerated power is returned to the smoothing circuit 12 side through the wheel motor control inverter 16. This means that the inertial energy stored in the flywheel device is effectively used in the crane motor IM, and that the rectifier input is stabilized.

In the present invention, the following embodiments are particularly preferred when the present invention is directed to a drive system of a crane using an engine generator as a power source.

■Set the release timing of inertial energy from the flywheel device to the peak cut of the rectifier input.

■Energy is stored in the flywheel device even when the engine generator is unloaded (crane or no-load state), that is, by absorbing and storing not only regenerated power but also surplus power in the engine.

Equalizes the engine output, that is, the rectifier input.

By using the engine in the manner described above, the engine can be downsized and fuel consumption can be reduced.

(Effects of the Invention) As described above, according to the two aspects of the present invention, it is possible to effectively utilize regenerative power generated in the crane motor in a crane while accumulating it through inverter control.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the main parts of a crane control device according to the present invention.

Claims (3)

[Claims] (1) In a crane equipped with a crane motor control inverter as means for controlling the crane motor, a flywheel device and the crane motor control inverter are used as means for absorbing and storing regenerative power generated by the crane motor. A flywheel control inverter connected in parallel to control a flywheel motor in the flywheel device, and a regeneration control section that sends a command signal based on a DC voltage to the crane motor control inverter. A crane control device characterized by: (2) The control device according to claim (1), comprising means for rectifying power supply voltage and a circuit for smoothing the rectified voltage as means for supplying DC voltage to the inverter for controlling the crane motor; The regeneration control section includes a means for detecting the voltage of the smoothing circuit, and a frequency command value for increasing the speed of the flywheel control inverter based on the detected value and set value by the voltage detecting means. 1. A crane control device comprising: arithmetic means for sending out signals. (3) In the control device according to claim (2), the regeneration control section includes means for detecting the input power to the rectifying means, and the calculating means is configured to detect the signal from the input power detecting means and the A crane control device characterized in that a frequency command value for deceleration is sent to the flywheel control inverter as the command signal based on a frequency feedback signal from the wheel control inverter.