JP3229145B2 - Regenerative power absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a regenerative power absorbing device in which a regenerative power is absorbed by a resistor in a variable speed drive system such as a crane utilizing a thyristor leonard or the like due to a situation where a generator is used as a power source. About.

[0002]

2. Description of the Related Art Conventionally, it is difficult to determine the turn-on time of each resistor for absorbing regenerative power unless the operation pattern is limited to one. Therefore, each resistor uses a large one designed with a continuous rating. There was waste to do.

[0003]

Since the regenerative power is not generated continuously for a long period of time, the average power supply frequency of each resistor is averaged to reduce the rated current carrying capacity of the resistor and reduce the size. I do. At the same time, by controlling the frequency of turning on each resistor, even if the operation pattern changes, a burnout accident is prevented. The present invention, in view of these,
It is an object of the present invention to provide a regenerative power absorbing device capable of realizing operation utilizing the capacity of the entire resistor effectively.

[0004]

A regenerative power absorbing device according to the present invention comprises a plurality of switchgears connected in parallel with a load circuit for generating regenerative electric power, and a resistor connected to the switchgear to consume the regenerative electric power. And a resistance input time management circuit that stores the number of times of opening and closing time of the switching device, a closing priority order determining circuit that determines the closing priority order of the switching device based on the input information from the resistance closing time management circuit, and a load circuit. A regenerative power calculation circuit for predicting the amount of regenerative power generated from a flowing current value;
A required resistance number calculation circuit that calculates the required number of resistors based on the calculation value from the regenerative power calculation circuit, and a required number of resistors calculated by the required resistance number calculation circuit and opening / closing based on the priority signal output from the closing priority determination circuit And a resistance input instruction circuit for outputting an input signal to the device.

[0005]

In the regenerative power absorbing device of the present invention, a plurality of switching devices are connected in parallel with a load circuit that generates regenerative power, and a resistor is connected to the switching device so that the regenerative power is consumed.
The number of times the switch is turned on and the turn-on time are stored in a resistance turn-on time management circuit, and the turn-on switch priority order is determined based on the turn-on information from the resistance turn-on time management circuit, and regenerative power is generated from the current flowing through the load circuit. Predict the quantity, calculate the required number of resistors by the calculated value from the regenerative power calculation circuit,
A switching signal is output to the switchgear according to the required number calculated by the required resistance calculating circuit and the priority signal output from the switching priority order determination circuit.

[0006]

Next, an embodiment of the regenerative power absorbing device of the present invention will be described. In FIG. 1, a contactor 5 is a plurality of switchgears connected in parallel with a DC motor 3 that generates regenerative power via a thyristor leonard 2.
Is powered by a generator 1 and is operated by a variable DC voltage DC-converted by a thyristor leonard 2. The resistor 4 is connected to the contactor 5 and consumes regenerative power. The resistance closing time management circuit 11 is connected to an auxiliary contact circuit (not shown) of the contactor 5 and stores the number of times the contactor 5 is closed and the closing time. The closing priority order determination circuit 12 is connected to the resistance closing time management circuit 11,
The closing priority order of the contactors 5 is determined based on the closing information from the resistance closing time management circuit 11. The regenerative power calculation circuit 8 is connected to the current detector 6, and predicts the amount of regenerative power generated from the current flowing through the DC motor 3. The required resistance calculating circuit 9 is connected to the regenerative power calculating circuit 8 and calculates the required number of the resistors 4 based on the calculated value from the regenerative power calculating circuit 8. The resistance input instruction circuit 10 is connected to the required resistance number operation circuit 9 and the input priority order determination circuit 12. An input signal is output to the contactor 5. The sequencer 7 includes a regenerative power operation circuit 8, a required resistance number operation circuit 9, a resistance input instruction circuit 10, a resistance input time management circuit 11
And an input priority order determining circuit 12.

That is, a circuit for converting the AC power of the generator 1 by the thyristor Leonard 2 and controlling the DC motor 3 at a variable speed has a plurality of resistors 4 for absorbing regenerative power,
Is connected to a power supply circuit, a current detector 6 for detecting a regenerative current between the DC motor 3 and the thyristor leonard 2, and a sequencer 7. In the sequencer 7, a regenerative power calculating circuit 8 for calculating regenerative power from the regenerative current detected by the current detector 6, a required resistor number calculating circuit 9 for calculating the number of resistors required for the regenerative power, It is determined by a resistor closing time management circuit 11 for managing the closing time of each resistor, a closing priority order determining circuit 12 for determining the next closing priority from a past closing time at a fixed cycle, and a closing priority order determining circuit 12. A resistor input instruction circuit 1 for selecting a resistor to be input based on the input priority and the required number of resistors calculated by the required resistor number operation circuit 9 and outputting an input command.
0.

Then, the regenerative power is calculated by the regenerative power calculating circuit 8 from the regenerative current detected by the current detector 6, and the required number of resistors is calculated by the required resistor number calculating circuit 9 from the calculated regenerative power. . On the other hand, from the command of the resistance input instruction circuit 10, the input time of each resistor is managed by the resistance input time management circuit 11 as follows.

T (t) = T (t−Δt) + aΔt... When the resistor is energized during Δt T (t) = T (t−Δt) −bΔt. ) ≧ 0.

Further, a and b are positive coefficients, and Δt is a unit time (for example, one second or a sequencer operation cycle).

From the input data of each resistor managed by the above equation, for example, at a constant period t of 30 seconds,
The priority of the next turn-on is increased in ascending order of the count value of the data T (t), the turn-on priority is determined by the turn-on priority determining circuit 12, and the required number of resistors is calculated according to the turn-on priority determined by the turn-on priority determining circuit 12. The necessary number of resistors 4 calculated by the circuit 9 are selected by the resistance input instruction circuit 10, and an input command is output to the contactor 5. If the data T (t) managed by the resistance injection time management circuit 11 has an abnormally large value, the alarm LED 13 outputs an alarm to warn the overheating of the resistor 4.

According to this embodiment, the turning-on frequency of each resistor is averaged, and even if the operation pattern is not constant and the variation pattern of the magnitude of the regenerative power is various, the resistance of the resistor by the average regenerative power is high. By designing, it is possible to make a resistor prepared conventionally smaller and less expensive. In addition, since the closing time is controlled, even when an abnormal closing such as overheating of the resistor is performed, an alarm can be output to prevent an accident such as burning. Furthermore, since each resistor has the same rating, it is possible to reduce the number of spares.
If the amount of regeneration or the time is increased, the same resistor can be added to cope with the problem, and there is an advantage that the content of the modification can be reduced.

In the present embodiment, the temperature of the resistor is managed by using a temperature curve and a cooling curve by energizing the resistor, instead of the equation used in the resistor injection time management circuit 11 for managing the resistor injection time. Then, in the order of the resistors having the lowest temperature, the next input priority is set higher and the input priority order determining circuit 1 is selected.
There is also a method of determining by 2. There is also a method in which the closing time management of the resistance closing time management circuit 11 is omitted, a random number generation circuit is added instead, and the closing priority order is determined by the closing priority order determination circuit 12 based on random numbers.

[0014]

According to the present invention, since a regenerative resistor can be used effectively, a smaller and less expensive system can be constructed as compared with the prior art, and an overheating accident of the resistor can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a regenerative power absorbing device showing one embodiment of the present invention.

[Explanation of symbols]

 8 Regenerative power operation circuit 9 Required resistance number operation circuit 10 Resistance input instruction circuit 11 Resistance input time management circuit 12 Input priority order determination circuit

Claims (1)

(57) [Claims] 1. A plurality of switchgear connected in parallel with a load circuit for generating regenerative power, a resistor connected to these switchgear to consume the regenerative power, the number of times the switchgear is turned on and on A resistance input time management circuit for storing time, a closing priority order determining circuit for determining a closing priority order of the switchgear based on input information from the resistance input time management circuit, and a regeneration based on a current value flowing through the load circuit. A regenerative power calculation circuit for estimating the amount of generated power, a required resistance number calculation circuit for calculating the required number of the resistors based on a calculation value from the regenerative power calculation circuit, and a calculation performed by the required resistance number calculation circuit. A resistance input instruction circuit that outputs an input signal to the switchgear according to a required number and a priority signal output from the input priority order determination circuit,
A regenerative power absorbing device comprising: