JP3755219B2 - Electric motor control equipment for industrial machinery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric motor control device for an industrial machine including a plurality of electric motors according to applications such as a battery forklift.
[0002]
[Prior art]
Conventionally, there is an industrial machine including a plurality of electric motors for each application.
For example, a battery forklift is equipped with two types of electric motors for traveling and cargo handling, and each of the main elements (power switching elements such as MOS-FETs) is controlled to be switched by a drive circuit or the like. Perform output control.
[0003]
FIG. 3 is a block diagram of a conventional battery forklift motor control device.
In the figure, a driving main element drive power supply 111 and a cargo handling main element drive power supply 114 are DC / DC converters that convert a voltage from a battery power supply, for example, a battery voltage of DC 48 (V), Convert to DC 18 (V).
[0004]
The traveling main element drive circuit 112 drives and controls the traveling main element 113 using electric power supplied from the traveling main element drive power supply 111. That is, switching control for turning ON / OFF the main element 113 for traveling is performed.
[0005]
Similarly, the cargo handling main element drive circuit 115 drives and controls the cargo handling main element 116.
As described above, in the conventional battery forklift motor control device, the drive power supply is prepared separately for traveling and cargo handling.
[0006]
This is because when one main element for driving and cargo handling is driven by one drive power source, if one of the main elements breaks for some reason, the effect on the drive power source and the other This is because the operation of the main element may be adversely affected. This is because, for example, an overcurrent flows through the drive circuit due to a failure of one main element and the output voltage of the drive power supply drops, thereby hindering the power supply to the normal main element.
[0007]
For this reason, conventionally, by dividing the circuit into two systems, for example, even if the main element for cargo handling 116 is broken and the fork does not operate, the circuit system on the main element side for traveling is not affected. I was trying not to affect driving.
[0008]
[Problems to be solved by the invention]
As described above, the conventional motor control device for a battery forklift can prevent the failure of one main element from interfering with the control operation of the other motor by dividing the circuit into two systems.
[0009]
However, in the configuration using the above-described two systems, the drive power supply is prepared separately for each circuit system, which increases the cost. In addition, the circuit configuration is complicated for two systems.
[0010]
The problem of the present invention is that, in an industrial machine having a plurality of electric motors for each application such as a battery forklift, a failure of a main element that operates the motor, which is also a case where the plurality of electric motors are operated by one drive power source, affects the other. This is to realize a reduction in cost of the motor control device and simplification of the circuit.
[0011]
[Means for Solving the Problems]
An electric motor drive control device according to the present invention is a common drive power supply that supplies electric power to each drive circuit that drives and controls a main element for output control of each electric motor in an industrial machine having a plurality of electric motors. And a failure detection means for detecting a failure of each main element, and when the failure of the main element is detected by the failure detection means, the drive power supply is connected via a drive circuit to which the influence of the failure of the main element corresponds. And preventive means for preventing this.
[0012]
The prevention means is, for example, a switch provided between each of the drive circuits and the drive power source, and disconnects the corresponding drive circuit from the drive power source when a failure of the main element is detected by the failure detection means. Consists of means.
[0013]
The switch means includes, for example, a semiconductor switching element, and the failure detection means inputs, for example, an input level for the main element and a state level that changes according to the operation of the main element, and the input level and the state level. A failure is detected based on the correspondence relationship, and when the failure is detected, the semiconductor switching element is turned off.
[0014]
The industrial machine is, for example, a battery forklift, and the plurality of electric motors are electric motors for traveling and cargo handling. The electric motor drive control device configured as described above drives main elements for output control of the plural electric motors. A common drive power supply is used for each drive circuit to be controlled. Even if a main element of a certain motor fails, the drive circuit that controls the drive of the failed main element is disconnected from the drive power supply by the switch means. Thus, other drive circuits are not affected by the influence. That is, if the main element of a certain motor breaks, an overcurrent flows through the drive circuit, the output voltage of the drive power supply drops, and this interferes with power supply to other normal main elements. There is nothing.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration of an electric motor control device according to an embodiment.
[0016]
In the figure, a driving / load handling element common drive power supply 11 includes a circuit system (travel main element drive circuit 12 and travel main element 13) for driving a travel motor, and a circuit system for driving a load handling motor ( This is a drive power supply common to both the cargo handling main element drive circuit 16 and the cargo handling main element 17). Like the conventional drive power supplies 111 and 114, a DC / DC that converts voltage from a battery power supply (not shown). It is a DC converter.
[0017]
The traveling main element drive circuit 12 drives and controls the traveling main element 13 based on electric power supplied from the traveling / load handling main element common drive power supply 11 and a control signal from a CPU (not shown).
[0018]
The traveling main element 13 is a power switching element for output control that is switched by the traveling main element drive circuit 12 and supplies electric power from a battery power source or the like to the traveling electric motor.
[0019]
The main element failure detector 14 serving as a failure detection means is a circuit that detects a failure of the traveling main element 13 and controls the switch 15 to be OFF when a failure is detected.
Details of the main element failure detector 14 will be described later with reference to FIG.
[0020]
The switch 15 as a switch means is a switch (semiconductor switching element) provided between the driving / load handling main element common drive power source 11 and the driving main element drive circuit 12, and is normally closed (ON). It has become. That is, during normal operation, power is supplied from the drive / load handling main element common drive power supply 11 to the drive main element drive circuit 12.
[0021]
When a failure of the main element 13 for traveling is detected by the main element failure detector 14 and a failure detection signal is sent, the switch 15 is opened (OFF). As a result, the travel drive circuit system (travel main element drive circuit 12, travel main element 13) is disconnected from the common drive power supply (travel / load handling main element common drive power supply 11). The failure of 13 does not hinder the operation of the cargo handling drive circuit system.
[0022]
That is, for example, even if an overcurrent flows through the traveling main element drive circuit 12 due to a failure of the traveling main element 13, the switch 15 is opened, so that the driving / loading main element common drive power supply 11 There is no impact. There is no hindrance to power supply from the common drive power source 11 for driving / loading main elements to the drive circuit system for cargo handling.
[0023]
The configuration of the cargo handling drive circuit system including the cargo handling main element drive circuit 16 and the cargo handling main element 17 is also substantially the same as the configuration of the traveling circuit system.
That is, the cargo handling main element drive circuit 16 drives and controls the cargo handling main element 17 based on the power supplied from the driving / load handling main element common drive power supply 11 and the control signal from the CPU (not shown). is there.
[0024]
The main element 17 for cargo handling is a power switching element for output control that is switched by the main element drive circuit 16 for cargo handling and supplies electric power from a battery power source or the like to the electric motor for traveling.
[0025]
The main element failure detector 18 as a failure detection means is a circuit that detects a failure of the main element 17 for cargo handling. When a failure is detected, the switch 19 is turned off.
A switch 19 as a switch means is a switch provided between the driving / load handling main element common drive power supply 11 and the load handling main element drive circuit 16 and is normally closed. That is, during normal times, the power supply line from the driving / load handling main element common drive power supply 11 to the cargo handling main element drive circuit 16 is connected.
[0026]
When the main element 17 for cargo handling fails, the main element failure detector 18 detects the failure and the switch 19 is turned off, so that the power supply line is disconnected. Therefore, the failure of the main handling element 17 does not adversely affect the operation of the traveling circuit system.
[0027]
FIG. 2 is a circuit configuration diagram of the motor control device according to the embodiment.
In the drawing, the circuit configuration on the driving circuit system side for traveling is described as being shown, but the circuit configuration on the driving circuit system side for cargo handling is also the same.
[0028]
In the same figure, what is substantially equivalent to the block configuration shown in FIG. 1 is surrounded by a broken line.
In FIG. 2, a PNP transistor 21 is a switching element provided on a power supply line from the traveling / load handling main element common drive power supply 11 to the traveling main element drive circuit 12. ON / OFF of the PNP transistor 21 is controlled by the NPN transistor 22.
[0029]
The output from the main element failure detector 14 is applied to the base side of the NPN transistor 22. When the main element is normal, “H” is input to the base, and the NPN transistor 22 is in the ON state. It has become. Thus, since the base side potential of the PNP transistor 21 is the ground potential, the PNP transistor 21 is in the ON state.
[0030]
When a failure of the main element is detected and the output from the main element failure detector 14 becomes “L” (corresponding to the above-described failure detection signal), the NPN transistor 22 is turned off, and thereby the PNP transistor 21 is turned off. The power supply line is disconnected.
[0031]
The NPN transistor 23 and the PNP transistor 24 are switching elements that constitute the traveling main element drive circuit 12.
A control signal from a CPU (not shown) is input to the bases of the NPN transistor 23 and the PNP transistor 24. The control signal is, for example, a PWM wave, and the output of the electric motor 26 is controlled (current control) by changing the duty ratio (ratio of H and L of the pulse width) to change the switching time of the traveling main element 13. ). The NPN transistor 23 and the PNP transistor 24 are ON / OFF controlled by a control signal input to the base thereof, and output the electric power supplied from the driving / loading main element common drive power supply 11 to the driving main element 13.
[0032]
The MOS-FET 25 is an example of the traveling main element 13 and is controlled to be switched by the output (control signal amplification output) from the traveling main element drive circuit 12 input to the gate thereof, thereby controlling the output of the electric motor 26. Is.
[0033]
The electric motor 26 is a traveling motor, and is driven and output by electric power supplied from the battery power source 27.
The main element failure detector 14 is based on the correspondence between the state (potential) on the gate G side as the input level of the MOS-FET 25 and the state (potential) on the drain D side as the state level. It is a circuit that determines whether or not it is normal.
[0034]
That is, when the MOS-FET 25 operates normally, if the gate G side is “H”, the MOS-FET 25 is turned on, so that the drain D side is “L” (ground potential). Similarly, if the gate G side of the MOS-FET 25 is “L”, its drain D side is “H”.
[0035]
The failure state of the MOS-FET 25 includes short circuit (short circuit), open circuit, and the like. When short-circuited, even if the gate G side is “L”, the drain D side is “L”. When open, even if the gate G side becomes “H”, the drain D side is “H”.
[0036]
The main element failure detector 14 is used for running when the detected two signals on the gate G side and the drain D side are “L” and “H”, respectively, or “H” and “L”. Assuming that the main element 13 is operating normally, “H” is output to the NPN transistor 22 of the switch 15.
[0037]
On the other hand, when the two detected signals are “L” “L” or “H” “H”, it is assumed that the main driving element 13 is faulty, and the NPN transistor of the switch 15 22 outputs “L”. Thus, the NPN transistor 22 is turned OFF and the PNP transistor 21 is turned OFF, so that the traveling main element drive circuit 12 is disconnected from the traveling / load handling main element common drive power supply 11.
[0038]
The main element failure detector 14 includes a Schottky barrier diode 28, a transistor 29, an inverter 30, an exclusive-NOR gate 31, and an inverter 32.
[0039]
For example, the transistor 29 is OFF when the potential on the drain D side of the MOS-FET 25 is 0 (V), and is ON when it is 50 (V).
When the transistor 29 is OFF, the output of the power source E (for example, 5V) is inverted by the inverter 30 and “L” is input to one input terminal of the Exclusive-NOR gate 31. When the transistor 29 is turned on, the inverted output from the inverter 30 becomes “H”.
[0040]
An output to the gate G side of the MOS-FET 25 from the traveling main element drive circuit 12 is input to the other input terminal of the Exclusive-NOR gate 31. Here, for example, when the output from the driving main element drive circuit 12 is “L”, the MOS-FET 25 is OFF when it is normal, so that the drain D side is “H” (for example, 50 (V)). Accordingly, since the transistor 29 is turned on, “H” is input to one input terminal of the exclusive-NOR gate 31. Since the output “L” from the driving main element drive circuit 12 is inputted to the other input terminal of the exclusive-NOR gate 31, the exclusive-NOR gate 31 has these “H” and “L”. “L” is output in response to the input. The “L” output is inverted by the inverter 32 and the inverted output “H” is applied to the base side of the NPN transistor 22 of the switch 15. As a result, the NPN transistor 22 is turned on and the PNP transistor 21 is controlled to be turned on, so that the switch 15 is normally connected to the driving / loading main element common drive power source 11 and the driving main element drive circuit. 12 is connected.
[0041]
On the other hand, when the MOS-FET 25 is faulty (for example, short-circuited), the drain D side becomes “L” (for example, 0 (V)). Therefore, “L” is output from the inverter 30 to one input terminal of the exclusive-NOR gate 31, and the output of the exclusive-NOR gate 31 is input to the input “L” “L”. In response, it becomes “H”. When this is inverted and output by the inverter 32, the NPN transistor 22 is turned off, so that the PNP transistor 21 is turned off.
[0042]
In addition, when the MOS-FET 25 is faulty (for example, open), even if the gate side input is “H”, the ON operation is not performed, so that the drain D side is “H” (for example, 50 (V)). . Accordingly, “H” “H” is input to the input terminal of the Exclusive-NOR gate 31, and “H” is output accordingly. When this is inverted and output by the inverter 32, the NPN transistor 22 is turned off, so that the PNP transistor 21 is turned off.
[0043]
As described above, the main element failure detector 14 detects that the MOS-FET 25 is not operating in accordance with the input signal on the gate G side based on the state of the gate G side and the drain D side of the MOS-FET 25. In such a case, the switch 15 is controlled to be OFF as a failure has occurred.
[0044]
As described above, when the traveling main element 13 fails, the traveling main element drive circuit 12 is disconnected from the traveling / load handling main element common drive power supply 11 by the switch 15. Therefore, an overcurrent does not flow through 12 and the output voltage of the driving / load handling main element common drive power supply 11 does not drop. Therefore, the operation of the cargo handling circuit system sharing the drive power supply 11 is not affected.
[0045]
In addition, the motor control apparatus of this invention is not restricted to the structure of the said Example. For example, a failure detection signal output from the main element failure detector 14 is input to a CPU (control means) (not shown) and input to the traveling main element drive circuit 12 (load handling main element drive circuit 16). The control signal from the CPU to be turned off may be controlled. Further, the main element failure detector 14 of the above embodiment shows an example of a circuit for detecting a failure of the main element, and the present invention is not limited to this, and other elements that can detect a failure of the main element. Any means may be used.
[0046]
Further, not only the failure detection of the main element but also the failure of the drive circuit may be detected and the switch may be controlled to be OFF.
The electric motor control device of the present invention is not limited to controlling each electric motor for traveling and cargo handling of a battery forklift. The present invention can be applied to general industrial machines including a plurality of electric motors (particularly for traveling and for other operations) provided according to applications.
[0047]
【The invention's effect】
As described above in detail, according to the motor control device for an industrial machine of the present invention, for example, even when each motor control device for traveling and cargo handling in a battery forklift is operated by one power source for driving, the main element Is detected, and the motor control device on the side where this failure is detected is disconnected from the drive power supply, so that the failure of one main element does not affect the other.
[0048]
As a result, the drive power supply can be shared into one without the problem that the failure of one main element affects the other, so that the circuit of the motor control device such as a battery forklift can be simplified and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an electric motor control device according to an embodiment.
FIG. 2 is a circuit configuration diagram of an electric motor control device according to an embodiment.
FIG. 3 is a block diagram showing the configuration of a conventional motor control device for a battery forklift.
[Explanation of symbols]
11 Driving / Handling Main Element Common Drive Power Supply 12 Traveling Main Element Drive Circuit 13 Traveling Main Element 14 Main Element Fault Detector 15 Switch 16 Cargo Handling Main Element Drive Circuit 17 Cargo Handling Main Element 18 Main Element Fault Detector 19 Switch 21, 24 PNP transistors 22, 23 NPN transistor 25 MOS-FET
26 Electric motor 27 Battery power supply 28 Schottky barrier diode 29 Transistor 30 Inverter 31 Exclusive-NOR gate 32 Inverter

Claims (3)

In industrial machines with multiple motors,
One shared drive power supply that supplies power to each drive circuit that drives and controls the main element for output control of each of the motors;
A failure detection means for detecting a failure of each of the main elements;
When failure of the main device is detected by said failure detection means, through the drive circuit the influence of a failure of the main device corresponding possess a prevention means for preventing the department及to the power supply for the drive,
The prevention means is provided between each of the drive circuits and the drive power supply, and when a failure of the main element is detected by the failure detection means, a switch means for disconnecting the corresponding drive circuit from the drive power supply. Consisting of
The switch means has a semiconductor switching element, and the failure detection means inputs an input level to the main element and a state level that changes according to the operation of the main element, and the correspondence relationship between the input level and the state level is established. A motor control device for an industrial machine, wherein a fault is detected based on the semiconductor switching element and the semiconductor switching element is turned off when the fault is detected . In industrial machines with multiple motors,
One shared drive power supply that supplies power to each drive circuit that drives and controls the main element for output control of each of the motors;
A failure detection means for detecting a failure of each of the main elements;
When a failure of the main element is detected by the failure detection means, there is a prevention means for preventing the influence of the failure of the main element from reaching the drive power supply via the corresponding drive circuit,
The motor control apparatus for an industrial machine according to claim 1, wherein the prevention means comprises control means for turning off a control signal for operating a corresponding drive circuit when a failure detection signal is input from the failure detection means . 3. The industrial machine motor control device according to claim 1, wherein the industrial machine is a battery forklift, and the plurality of electric motors are electric motors for traveling and cargo handling.

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