JP2012135164A - System for controlling motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately recover regenerative power of a motor and effectively use the regenerative power.SOLUTION: A motor power circuit 13 has capacitors 26, 27 and switches 31, 32 in power paths 24, 25, respectively. Power paths 46, 48 connecting the power paths 24, 25 to a power path 43 of a control power circuit 15 have switches 47, 49. In a motor regeneration period, a control circuit 14 closes either of the switches 31, 32 and opens the other, and controls on/off the switches 47, 49 in response to the opening/closing states of the switches 31, 32. In this state, the control circuit 14 switches the opening/closing states of the switches 31, 32, 47, 49.

Description

  The present invention relates to a control system for a motor provided, for example, in a movable part of an industrial robot.

  An AC servo motor provided in a movable part such as a joint part of an industrial robot realizes a desired operation by repeatedly performing acceleration control and deceleration control. In this case, various technologies have been proposed in which regenerative power is generated when the motor is decelerated and the regenerative power is recovered using a regenerative resistor. For example, in Patent Document 1, the switching element connected between the DC power supply lines via the regenerative resistor is turned on, and the regenerative power from the motor is bypassed to the DC power supply line side and controlled to be consumed by the regenerative resistor. Yes.

JP 2007-37301 A

  However, in the configuration in which the motor regenerative power is recovered (consumed) by the regenerative resistor, heat is generated in the regenerative resistor, which may cause an influence on the robot controller or the like. In this regard, in order to reduce the influence of heat generation due to the regenerative resistor, it is necessary to take measures such as providing a radiator in the robot controller. Here, in order to simplify heat countermeasures using a radiator or the like and to suppress the influence of heat on the robot controller or the like, it is desired to construct a technique for suppressing heat generation during motor regeneration. On the other hand, the existing technology releases regenerative power (regenerative energy) as heat, and it is considered that there is room for improvement from the viewpoint of energy.

  The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a motor control system that can suitably recover the regenerative power of the motor and can effectively use the regenerative power. Is.

  Hereinafter, means and the like effective for solving the above-described problems will be described while showing functions and effects as necessary.

The first invention is
A first power supply circuit that generates DC power for driving the motor from AC power;
An inverter circuit for driving a motor by converting DC power supplied from the first power supply circuit into drive power;
A second power supply circuit for generating DC power for driving the control circuit from the AC power;
A control circuit driven by DC power supplied from the second power supply circuit;
A motor control system that controls the rotation of the motor by controlling the inverter circuit by the control circuit,
The first power supply circuit has a plurality of first power paths for supplying DC power for driving the motor to the inverter circuit, and collects regenerative power during motor regeneration in the plurality of first power paths. A possible capacitor and a first opening / closing means for opening / closing the connection between the capacitor and the inverter circuit,
A connection path is connected to each of the plurality of first power paths, and each of the second power paths outputs the DC power for driving the control circuit in the second power supply circuit via the plurality of connection paths. 1 power path is connected,
The plurality of connection paths are provided with second opening / closing means for opening and closing each of the connection paths,
In a motor regeneration period in which regeneration of the motor is performed, the first opening / closing means of any one of the plurality of first power paths is closed and the first opening / closing means of the other first power path is The first opening / closing means is opened, the second opening / closing means of the connecting path connected to the closed first power path is opened, and the first opening / closing means is connected to the opened first power path. Opening and closing control means for closing the second opening and closing means of the connecting path,
Similarly, in the motor regeneration period, switching of the open / close state is performed for the plurality of first opening / closing means provided in the plurality of first power paths and the plurality of second opening / closing means provided in the plurality of connection paths, respectively. Switching means to
It is characterized by providing.

  According to the above configuration, during the motor regeneration period, the first opening / closing means of any one of the plurality of first power paths is closed and the first opening / closing means of the other first power paths is opened. Thus, at least at a certain timing during motor regeneration, regenerative power is recovered by only one of a plurality of capacitors (capacitors provided in a plurality of first power paths). Further, during the motor regeneration period, the second opening / closing means connected to the first power path closed by the first opening / closing means is opened, and the first power path opened by the first opening / closing means is opened. In order to close the second opening / closing means of the connected connection path, the capacitors that are recovering the regenerative power among the plurality of capacitors are not connected to the second power supply circuit side, and the capacitors that are not recovering the regenerative power are the second power supply circuit side Will be connected. That is, the second power supply circuit side can be supplied with power from any of the plurality of capacitors that are not recovering the regenerative power via any of the connection paths. In this case, of the plurality of capacitors, any one of the capacitors is used for recovery of regenerative power, and the other capacitors are used as a power supply source to the second power supply circuit.

  Further, during the motor regeneration period, switching of the open / close state is performed for the plurality of first opening / closing means provided in the plurality of first power paths and the plurality of second opening / closing means respectively provided in the plurality of connection paths. Because of the configuration, when each capacitor is viewed, recovery of regenerative power and supply of the recovered power to the second power supply circuit side are performed alternately. Therefore, even if regenerative power cannot be recovered with one capacitor, recovery of regenerative power with another capacitor can be continued. By repeating this alternately, no regenerative resistor is required or a regenerative resistor is provided. Even if it is, it becomes possible to suppress the heat_generation | fever as much as possible. Therefore, it is possible to simplify heat countermeasures using a radiator or the like. Further, the regenerative power (regenerative energy) collected by the capacitor can be used for driving the control circuit. As a result, the regenerative power of the motor can be suitably recovered, and the regenerative power can be effectively used.

  In the second aspect of the present invention, during the motor regeneration period, the power storage amount of the plurality of capacitors provided in the plurality of first power paths, respectively, for which the power is being recovered, has reached a predetermined amount. Determination means for determining whether or not the determination has been made. When the determination unit determines that the storage amount of the capacitor during power recovery has reached a predetermined amount, the switching unit stops recovery of regenerative power for the capacitor during power recovery, and has already been recovered. In order to start the supply of the electric power to the second power supply circuit side, switching of the open / close state of the first open / close means and the second open / close means is performed.

  According to the above configuration, the switching between the open / close states of the first opening / closing means and the second opening / closing means is performed at the time when the amount of power stored in the recovering capacitor where the regenerative power is being recovered reaches a predetermined amount. As a result, the recovery of the regenerative power is stopped for the capacitor during power recovery, and the supply of the recovered power to the second power supply circuit side is started. In this case, it is possible to switch from the power recovery of the capacitor to the power supply in a state where the amount of power stored in the capacitor during power recovery is sufficient, and the power supply to the second power supply circuit side after the switching Can be suitably implemented.

  In a third aspect, the second power supply circuit has a power switch that cuts off the supply of the AC power from the AC power supply, and includes means for opening the power switch during the regeneration period of the motor.

  According to the above configuration, the supply of AC power to the second power supply circuit is stopped during the motor regeneration period. Therefore, it can be said that this is a desirable configuration from the viewpoint of energy saving because the consumption of AC power for driving the control circuit can be reduced.

  In a fourth aspect of the invention, the second power supply circuit performs power supply to the control circuit side by supplying the AC power from an AC power supply in the motor regeneration period. In the motor regeneration period, Of the capacitor that is recovering regenerative power in the first power supply circuit and the capacitor that is supplying power to the second power supply circuit, the amount of electricity stored in the capacitor that is supplying power Means for detecting. When the storage amount of the capacitor being supplied with power is reduced to zero or near zero, the switching unit replaces the capacitor whose storage amount is reduced to zero or near zero with the regenerative power recovery capacitor. In order to switch to, the switching of the open / close state of the first opening / closing means and the second opening / closing means is performed.

  In short, in the configuration in which one capacitor is provided in the first power supply circuit, the capacitor storage amount (charge voltage) when the motor is driven depends on the path voltage (bus voltage) in the power path. In this case, the regenerative power recovery capability during the motor regeneration period depends on the capacitor power storage amount at the start of regeneration, that is, the path voltage when the motor is driven. For this reason, there is a concern that the capacitor may limit power recovery during the motor regeneration period. Even if a plurality of capacitors are provided in the first power supply circuit, as long as the recovery power of the regenerative power depends on the path voltage when the motor is driven as described above, the motor regeneration is similarly performed. There is concern that there will be restrictions on power recovery during the period.

  In this regard, according to the above configuration, in the configuration in which a plurality of capacitors are provided in the first power supply circuit, when the charged amount of the capacitor that is supplying power is reduced to zero or near zero (the charged amount is almost the same). The switching operation of each open / close means is performed so that the capacitor in which the amount of stored power is reduced to zero or near zero is switched to the regenerative power recovery capacitor. As a result, the capacitor from which the recovery of the regenerative power is started has a higher regenerative power recovery capability than the case where the capacitor storage amount at the start of the power recovery is the path voltage when the motor is driven. Therefore, restrictions on power recovery can be relaxed, and recovery efficiency of regenerative power can be improved.

The block diagram which shows the outline | summary of a motor control system. The circuit diagram for demonstrating the state of operation | movement of a motor power supply circuit and a control power supply circuit. The time chart for demonstrating switching of each switch and transition of the voltage of each capacitor | condenser in a motor regeneration period. The flowchart which shows the procedure of collection | recovery control of motor regenerative electric power.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. In the present embodiment, a control system for an AC servo motor incorporated in a movable part (joint part) of an industrial robot is embodied. First, an outline of the system will be described with reference to FIG.

  As shown in FIG. 1, this control system has, as main components, a motor (AC servomotor) 11 provided in a robot body, an inverter circuit 12 that drives the motor 11, and AC power for driving the motor. A motor power supply circuit 13 for generating DC power, a control circuit 14 for controlling the motor 11 by controlling the inverter circuit 12, and a control power supply circuit 15 for generating DC power for driving the control circuit from the AC power are provided. ing. Next, the configuration of the motor power circuit 13 will be described.

  In the motor power supply circuit 13, a rectifier circuit 23 is connected to the AC power supply 21 via a power switch 22 for driving the motor. The power switch 22 is composed of a semiconductor switch such as a MOSFET, and is provided as a two-pole single-throw switch in which contacts are provided on a pair of power lines between the AC power source 21 and the rectifier circuit 23 (each described later). The same applies to the switch). The rectifier circuit 23 is composed of, for example, a bridge full-wave rectifier circuit composed of four diodes. The rectifier circuit 23 converts AC power into DC power. For example, AC power of AC 200 V is output from the AC power source 21, and the AC power is rectified by the rectifier circuit 23, whereby DC power of DC 280 V is output from the rectifier circuit 23. A mechanical switch can be used as the power switch 22, and a single-pole single-throw switch can be used instead of the two-pole single-throw switch (the same applies to the power switch 41 described later).

  Two power paths 24 and 25 for outputting DC power (DC power for driving the motor) to the inverter circuit 12 are connected to the output side of the rectifier circuit 23. These power paths 24 and 25 are connected to the power paths 24 and 25, respectively. The capacitors 26 and 27 constituting the smoothing circuit are connected. Specifically, the power path 24 includes a pair of power lines 24a and 24b, and a first capacitor 26 is connected between the power lines 24a and 24b. The power path 25 includes a pair of power lines 25a and 25b, and a second capacitor 27 is connected between the power lines 25a and 25b. In the present embodiment, the two capacitors 26 and 27 having the same storage capacity are used.

  The inverter circuit 12 is connected to the power paths 24 and 25 in parallel with the capacitors 26 and 27. The inverter circuit 12 includes a three-phase inverter circuit. The inverter circuit 12 converts DC power into three-phase AC power, and the three-phase AC power is supplied to the motor 11 as drive power. The motor 11 is driven by the supply of drive power from the inverter circuit 12.

  In the power path 24 (power lines 24a and 24b), a switch 31a is provided between the rectifier circuit 23 and the first capacitor 26, and a switch 31b is provided between the first capacitor 26 and the inverter circuit 12. . In the power path 25 (power lines 25a and 25b), a switch 32a is provided between the rectifier circuit 23 and the second capacitor 27, and a switch 32b is provided between the second capacitor 27 and the inverter circuit 12. ing.

  In such a case, the switches 31a and 31b provided in the power path 24 are simultaneously opened and closed, and these switches 31a and 31b are hereinafter collectively referred to as “first switch 31”. By turning on (closing) the first switch 31, power is supplied from the rectifier circuit 23 to the inverter circuit 12 through the power path 24, and by turning off (opening) the first switch 31, The power supply to the inverter circuit 12 is cut off, and the first capacitor 26 is electrically disconnected from the rectifier circuit 23 and the inverter circuit 12. During regeneration of the motor 11, the first switch 31 is turned on (closed), whereby the regenerative power is recovered through the power path 24 in the first capacitor 26.

  Further, the switches 32a and 32b provided in the power path 25 are opened and closed at the same time. Hereinafter, these switches 32a and 32b are collectively referred to as a “second switch 32”. By turning on (closing) the second switch 32, power is supplied from the rectifier circuit 23 to the inverter circuit 12 through the power path 25, and by turning off (opening) the second switch 32, The power supply to the inverter circuit 12 is cut off, and the second capacitor 27 is electrically disconnected from the rectifier circuit 23 and the inverter circuit 12. During regeneration of the motor 11, the second switch 32 is turned on (closed), whereby the regenerative power is recovered through the power path 25 in the second capacitor 27.

  The switches 31a and 31b may not be opened / closed at the same time, and may be opened / closed with a time difference. The same applies to the switches 32a and 32b. In the present embodiment, the motor power supply circuit 13 corresponds to a “first power supply circuit”, the power paths 24 and 25 correspond to “a plurality of first power paths”, and the switches 31 and 32 serve as “first opening / closing means”. Equivalent to.

  In the control power supply circuit 15, a rectifier circuit 42 is connected to the AC power supply 21 via a control power supply switch 41. Like the rectifier circuit 23, the rectifier circuit 42 is composed of a bridge full-wave rectifier circuit. The rectifier circuit 42 converts AC power of AC 200V into DC power of DC 280V. A power path 43 including a pair of power lines 43 a and 43 b is connected to the output side of the rectifier circuit 42, and a capacitor 44 constituting a smoothing circuit is connected to the power path 43. The power path 43 is connected to a transformer (DCDC converter) 45 that converts the output voltage (for example, DC280V) of the rectifier circuit 42 into a predetermined constant voltage (for example, DC5V).

  The power path 24 (power lines 24a and 24b) of the motor power circuit 13 and the power path 43 (power lines 43a and 43b) of the control power circuit 15 are connected by a power path 46 including a pair of power lines 46a and 46b. A third switch 47 is provided in the power path 46. The third switch 47 is turned off (opened) in the driving state of the motor 11, and is turned on (closed) during motor regeneration as will be described later, whereby the power path 24 (specifically, each electrode of the first capacitor 26). ) And the power path 43 are conducted through the power path 46. The power path 25 (power lines 25a and 25b) of the motor power circuit 13 and the power path 43 (power lines 43a and 43b) of the control power circuit 15 are connected by a power path 48 including a pair of power lines 48a and 48b. In the power path 48, a fourth switch 49 is provided. The fourth switch 49 is turned off (opened) in the driving state of the motor 11, and is turned on (closed) during motor regeneration as will be described later, whereby the power path 25 (specifically, each electrode of the second capacitor 27). ) And the power path 43 are conducted through the power path 48.

  In this embodiment, the control power supply circuit 15 corresponds to a “second power supply circuit”, the power path 43 corresponds to a “second power path”, and the power paths 46 and 48 correspond to “a plurality of connection paths”. The switches 47 and 49 correspond to “second opening / closing means”.

  The control circuit 14 is a known logical operation circuit having a CPU, various memories, an input / output circuit, and the like, and performs various motor controls by a control program stored in the memory. For example, the rotation of the motor 11 is controlled by controlling a plurality of switching elements provided in the inverter circuit 12 by a PWM signal. In this case, the control circuit 14 performs position feedback control of the motor 11 based on a detection signal of a rotary encoder (position detection means) (not shown). Further, the control circuit 14 includes a voltage detection unit 51 that detects a charging voltage (V1 in the figure) of the first capacitor 26 and a voltage detection unit 52 that detects a charging voltage (V2 in the figure) of the second capacitor 27. The detection results of these voltage detectors 51 and 52 are appropriately output to the control circuit 14.

  When the motor is driven, the motor 11 is driven as a series of operation patterns of acceleration → constant speed → deceleration. In other words, the motor 11 is first accelerated to a predetermined speed at a constant acceleration (positive acceleration) from a state in which the motor speed = 0 during the acceleration period, and thereafter is maintained at the predetermined speed during the constant speed period. Thereafter, the motor speed is reduced to zero at a constant acceleration (negative acceleration). The motor deceleration period corresponds to the motor regeneration period.

  In the present embodiment, in the motor regeneration period, the control circuit 14 controls each switch to optimize the recovery of the regenerative power and to effectively use the regenerative power, and the first capacitor 26 and the second capacitor 27 are connected to the power. Either a state that fulfills the role of recovery or a state that serves as the power source of the control circuit 14 is used, and both of these states are alternately switched by the capacitors 26 and 27. Details will be described below.

  The motor power supply circuit 13 and the control power supply circuit 15 are basically controlled by switching three states, and each state will be described with reference to FIG. In FIG. 2, (a) shows the circuit state when the motor is driven (other than during regeneration), and (b) and (c) show the circuit state during motor regeneration. In FIG. 2, for convenience of explanation, the power path that is interrupted by the switch-off is not illustrated, and only the power path that is conducted is illustrated. Note that the power switch 22 of the motor power supply circuit 13 is always turned on since it is not turned off until the end of the work when it is turned on at the start of the robot work.

At the time of driving the motor shown in FIG.
Power switch 41 = on (closed),
First switch 31 = on (closed),
Second switch 32 = off (open),
Third switch 47 = off (open),
4th switch 49 = off (open),
In such a state, DC power is output from the rectifier circuit 23 to the inverter circuit 12 via the power path 24. Note that the output voltage of the rectifier circuit 23 is, for example, 280V, and the voltage V1 of the first capacitor 26 is maintained at approximately 280V. In this case, the power path 24 of the motor power supply circuit 13 and the power path 43 of the control power supply circuit 15 are electrically separated, and the control circuit 14 has drive power generated by the power supplied from the rectifier circuit 42. Is supplied.

  The power switch 41 is preferably driven to be switched so as to keep the primary side of the transformer 45 at the minimum operating voltage. In addition to being kept in the ON state, the power switch 41 is set to the primary side voltage (voltage V3 in the figure) each time. The on / off control may be performed accordingly.

Further, at the time of motor regeneration shown in FIG.
Power switch 41 = off (open),
First switch 31 = off (open),
Second switch 32 = on (closed),
Third switch 47 = on (closed),
4th switch 49 = off (open),
In this state, the regenerative power of the motor 11 flows through the power path 25 and is collected by the second capacitor 27. In this case, the first capacitor 26 and the power path 43 of the control power supply circuit 15 are electrically connected via the power path 46, and the control circuit 14 is generated by the power supplied from the first capacitor 26. Driving power is supplied.

In addition, at the time of motor regeneration shown in FIG.
Power switch 41 = off (open),
First switch 31 = on (closed),
Second switch 32 = off (open),
Third switch 47 = off (open),
4th switch 49 = on (closed),
In this state, the regenerative power of the motor 11 flows through the power path 24 and is collected by the first capacitor 26. In this case, the second capacitor 27 and the power path 43 of the control power supply circuit 15 are electrically connected via the power path 48, and the control circuit 14 is generated by the power supplied from the second capacitor 27. Driving power is supplied.

  In the following description, the state shown in FIG. 2A is called a first control state, the state shown in FIG. 2B is called a second control state, and the state shown in FIG. 2C is called a third control state.

  When the motor 11 transitions from the drive state to the regenerative state, the control states shown in FIGS. 2A to 2C are appropriately switched during the motor regeneration period in which the motor regeneration is performed. The switching of each control state and the transition of the voltage of each capacitor will be described with reference to the time chart of FIG. In FIG. 3, the period before the timing t1 is a constant speed period of the motor 11, and the timings t1 to t5 are a motor regeneration period.

  Before the timing t1, the switches of the motor power supply circuit 13 and the control power supply circuit 15 are controlled to the first control state (the state shown in FIG. 2A). At this time, the voltage V1 of the first capacitor 26 of the motor power supply circuit 13 and the voltage V3 of the capacitor 44 of the control power supply circuit 15 are respectively maintained at the reference value (280V), and the voltage V2 of the second capacitor 27 is 0V. It has become.

  When the motor regeneration is started at the timing t1, the first control state is maintained at the beginning of the regeneration, and the voltage V1 of the first capacitor 26 increases due to the recovery (storage) of the motor regeneration power in this state. Then, when the voltage V1 of the first capacitor 26 rises to a predetermined threshold voltage Vth1, a transition from the first control state to the second control state is performed (timing t2). The threshold voltage Vth1 is preferably determined based on the breakdown voltage of the first capacitor 26, and is, for example, 400V.

  At timing t2, since the first capacitor 26 and the power path 43 of the control power supply circuit 15 are electrically connected via the power path 46 in a state where the voltage V1> the voltage V3, the voltage V1 decreases after t2, The voltage V3 increases. Further, the voltage V2 of the second capacitor 27 increases by recovering the motor recovered power. At timing t2, since the voltage V2 of the second capacitor 27 is sufficiently low (initial voltage≈0), the recovery of the regenerative power can be suitably performed. Therefore, the influence on the deceleration of the motor 11 can be suppressed.

  After timing t2, the supply of AC power to the control power supply circuit 15 is stopped by turning off the power switch 41. Instead of this, power supply (energy supply) from the first capacitor 26 is performed. The drive of the control circuit 14 is continued.

  Thereafter, when voltage V1 = voltage V3 at timing t3, the voltage V3 starts to decrease and decreases together with the voltage V1.

  Thereafter, when the voltage V2 of the second capacitor 27 rises to a predetermined threshold voltage Vth2, the transition from the second control state to the third control state is performed (timing t4). The threshold voltage Vth2 is preferably determined based on the breakdown voltage of the second capacitor 27, and is, for example, 400V. At this time, since the second capacitor 27 and the power path 43 of the control power supply circuit 15 are electrically connected via the power path 48 in a state where the voltage V2> the voltage V3, the voltage V2 decreases after t4, V3 rises. Further, the voltage V1 of the first capacitor 26 increases by recovering the motor recovered power. Note that the voltage V1 (recovery start voltage) of the first capacitor 26 at the timing t4 is desirably lower than the reference value (280V). Subsequent processing in the motor regeneration period will not be described because the above-described operation is repeated.

  Then, at the timing t5 when the motor regeneration ends, the first control state is restored. As a result, the voltages V1 and V3 return to the reference value (280V), respectively, and the voltage V2 returns to 0V.

  Next, the motor regenerative power recovery control executed by the control circuit 14 will be described in detail with reference to the flowchart of FIG. This process is repeatedly executed by the control circuit 14 at a predetermined cycle.

  In FIG. 4, first, in step S11, it is determined whether or not it is currently a motor regeneration period. If it is not the motor regeneration period, this process is terminated as it is, and if it is the motor regeneration period, the process proceeds to the subsequent step S12.

  In step S12, it is determined whether or not the control is currently being performed in the first control state. In the present embodiment, control in the first control state is first performed at the beginning of motor regeneration. Step S12 is YES at the beginning of motor regeneration, and the process proceeds to step S13.

  In step S13, the voltage V1 of the first capacitor 26 is read, and in the subsequent step S14, it is determined whether or not the voltage V1 is equal to or higher than a predetermined threshold voltage Vth1. If V1 <Vth1, the process proceeds to step S15, and the control in the first control state is continued. If V1 ≧ Vth1, the process proceeds to step S16 to shift from the control in the first control state to the control in the second control state.

  When the shift to the control in the second control state is made, thereafter, step S12 becomes NO every time, and the process proceeds to step S17. In step S17, it is determined whether or not the control is currently being performed in the second control state. If YES, the process proceeds to step S18.

  In step S18, the voltage V2 of the second capacitor 27 is read, and in the subsequent step S19, it is determined whether or not the voltage V2 is equal to or higher than a predetermined threshold voltage Vth2. If V2 <Vth2, the process is terminated as it is, and the control in the second control state is continued. If V2 ≧ Vth2, the process proceeds to step S20 to shift from the control in the second control state to the control in the third control state.

  When the shift to the control in the third control state is made, thereafter, steps S12 and S17 are NO each time, and the process proceeds to step S21. In step S21, the voltage V1 of the first capacitor 26 is read. In the subsequent step S22, it is determined whether or not the voltage V1 is equal to or higher than a predetermined threshold voltage Vth1. If V1 <Vth1, the process is terminated as it is, and the control in the third control state is continued. If V1 ≧ Vth1, the process proceeds to step S23 to return from the control in the third control state to the control in the second control state.

  Thereafter, while the motor regeneration state continues, the control in the second control state and the control in the third control state are alternately performed in steps S17 to S23.

  According to the embodiment described in detail above, the following excellent effects can be obtained.

  During the motor regeneration period, one of the switches 31 and 32 of the power paths 24 and 25 is closed and the other is opened, and the switches provided in the power paths 46 and 48 according to the opening and closing of the switches 31 and 32 47 and 49 are controlled to be opened and closed, and switching of the open / close state of each of the switches (first to fourth switches) is further performed. As a result, one of the capacitors 26 and 27 (capacitor during recovery of regenerative power) is not connected to the control power supply circuit 15 side, and the other (capacitor during recovery of regenerative power) is connected to the control power supply circuit 15 side. Thus, the capacitors 26 and 27 can simultaneously collect the regenerative power and supply power to the control power supply circuit 15 side.

  In addition, since each switch (first to fourth switches) is alternately switched on / off during the motor regeneration period, the regenerative power is recovered and the control power circuit 15 for the recovered power is seen by looking at each capacitor. The supply to the side is performed alternately. Therefore, even if the regenerative power cannot be recovered by one capacitor, the regenerative power can be continuously recovered by the other capacitor. By repeating this alternately, the regenerative resistor is unnecessary in the motor power supply circuit 13, or Even if the regenerative resistor is provided, it is possible to suppress the heat generation as much as possible. Therefore, it is possible to simplify heat countermeasures using a radiator or the like. Further, the regenerative power (regenerative energy) collected by the capacitors 26 and 27 can be used for driving the control circuit 14. As a result, the regenerative power of the motor 11 can be suitably recovered and the regenerative power can be effectively used.

  During the motor regeneration period, it is determined whether or not the charging voltage (storage amount) has reached a predetermined value for the capacitor that is recovering power, and if it is determined that the charging voltage has reached the predetermined value, With regard to the capacitor, the switches 31 and 32 are switched on / off in order to stop the recovery of the regenerative power and start the power supply to the control power supply circuit 15 side. As a result, power supply to the control power supply circuit 15 side can be started in a state where the power collecting capacitor is fully charged or equivalent, and power supply as power supply power can be suitably implemented.

  Since the control power supply circuit 15 is configured to open the power switch 41 that cuts off the supply of AC power during the motor regeneration period, the supply of AC power to the control power circuit 15 is stopped during the motor regeneration period. Therefore, it can be said that the consumption of AC power for driving the control circuit 14 can be reduced, which is a desirable configuration from the viewpoint of energy saving.

[Other Embodiments]
The present invention is not limited to the description of the above embodiment, and may be implemented as follows, for example.

  In the above embodiment, when the charging voltage (storage amount) reaches a predetermined value for the capacitor that is recovering power during the motor regeneration period, the recovery of the regenerative power is stopped and recovered for the capacitor that is recovering power. The power is supplied to the control power supply circuit 15 side. That is, the configuration is such that the capacitor for recovering power is switched based on the charging voltage (charged amount) of the capacitor during power recovery. You may change about this point as follows. For example, in the motor regeneration period, when the power recovery time (charging time) of one capacitor reaches a predetermined time, the recovery of the regenerative power is stopped and the recovered power is recovered for the capacitor that is recovering the power. The supply to the control power supply circuit 15 side may be started. In other words, the capacitor for power recovery is switched based on the power recovery time of the capacitor.

  In the above embodiment, the capacitors 26 and 27 provided in the power paths 24 and 25 of the motor power supply circuit 13 have the same storage capacity. However, this is changed to use a capacitor having a different storage capacity. May be. In this case, for example, “the storage capacity of the capacitor 26> the storage capacity of the capacitor 27”, the power is smoothed using the capacitor 26 when the motor is driven (acceleration and constant speed), and the motor is regenerated (deceleration). In this case, it is preferable to collect the regenerative power and supply power to the control power supply circuit by using both capacitors 26 and 27. In this case, the capacitor 26 functions as a main capacitor, and the capacitor 27 functions as a sub capacitor.

  The motor power supply circuit 13 has a configuration in which three or more power paths (first power paths) are provided, capacitors are provided in the power paths, and the capacitors are used properly. Also good. For example, a configuration in which three power paths (first power paths) are provided in the motor power supply circuit 13 is controlled by the control circuit 14 in the motor regeneration period. Switching means), three switches (second opening / closing means) provided in three connection paths connecting the motor power supply circuit 13 and the control power supply circuit 15, and a power switch 41 of the control power supply circuit 15.

  In this case, the control circuit 14 turns on (closes) any one of the three switches of the motor power supply circuit 13 and turns off (opens) the other two switches during the motor regeneration period. The switch of one connection path connected to the power path in which the switch is turned on in 13 is turned off (opened), and the two connection paths connected to the power path in which the switch is turned off in the motor power supply circuit 13 Switch on (close). Further, the control circuit 14 determines which of the three switches (first opening / closing means) of the motor power circuit 13 and the three switches (second opening / closing means) of the connection path are turned on (closed) and turned off (opened). Then, switching is performed as appropriate based on the capacitor storage amount and the storage time. As described above, the motor regenerative power is recovered using one of the three capacitors, and the power is supplied to the control power supply circuit 15 using the other two. In the motor regeneration period, the motor regeneration power may be collected using two of the three capacitors, and the power may be supplied to the control power supply circuit 15 using the other one.

  In the above embodiment, the power switch 41 of the control power supply circuit 15 is turned off (opened) during the motor regeneration period, but this is changed and the power switch 41 of the control power supply circuit 15 is turned on (closed) during the motor regeneration period. ) May be used. In this case, the control power supply circuit 15 supplies power to the control circuit 14 side by supplying AC power from the AC power supply 21 even during the motor regeneration period.

  As described above, when the control power supply circuit 15 supplies power to the control circuit 14 side by supplying AC power from the AC power supply 21 even during the motor regeneration period, the capacitor switching is performed as follows. May be implemented. That is, the control circuit 14 has a capacitor (one of the capacitors 26 and 27) that is recovering regenerative power during the motor regeneration period and a capacitor (capacitor 26) that is supplying power to the control power supply circuit 15 side. , 27), the charging voltage (charged amount) of the capacitor being supplied with power is detected, and when the detected charging voltage drops to zero (or even near zero), the capacitor Is switched on / off in order to switch to a regenerative power recovery capacitor.

  According to the above configuration, in the capacitor where the recovery of the regenerative power is started during the motor regeneration period, the capacitor charging voltage at the start of the power recovery is the path voltage when the motor is driven (the output voltage of the rectifier circuit 23, for example, 280V). Compared with the case where it becomes, the collection | recovery capability of regenerative electric power will become high enough. Therefore, restrictions on power recovery can be relaxed, and recovery efficiency of regenerative power can be improved.

  Here, when multiple motors are used and the capacity of each motor is different, and even when the same capacity motor is used, the generation of regenerative power varies depending on the situation. (When it is performed at the fastest or unexpectedly loosely), there is a pattern in which the regenerative power returned from the small-capacity motor is low voltage, or even a large-capacity motor returns low voltage regenerative power However, regenerative power having a voltage higher than the charging voltage (charged amount) already stored in the capacitor does not always return. Such a situation means that there is regenerative power that cannot be recovered in the first place. In this regard, according to the above configuration, even if the regenerative power returned from each motor varies widely, the loss of power recovery can be reduced, and the recovery of regenerative power can be suitably performed.

  -During the motor regeneration period, the charging voltage VX1 of the capacitor (one of the capacitors 26 and 27) for which the regenerative power is being collected is detected, and the capacitor (capacitor for which power is being supplied to the control power supply circuit 15 side) On the other hand, the switches 31 and 32 are turned on / off to switch between the regenerative power recovery capacitor and the power supply capacitor based on the result of relative comparison between the charge voltages VX1 and VX2. It is good also as a structure which implements switching. Specifically, the control circuit 14 determines whether or not the charging voltage VX1 becomes larger than “charging voltage VX2 + α (α> 0)” during the motor regeneration period, and when VX1> VX2 + α is satisfied, the regeneration is performed. Replace the capacitor that is collecting power and the capacitor that is supplying power. α is the allowable voltage difference of the capacitor when switching from discharging to charging.

  According to the above configuration, when any one of the plurality of capacitors shifts from the power supply (power consumption) state to the power recovery state, the voltage difference at the beginning of capacitor charging (the charge voltage and the regenerative power voltage (Difference) can be reduced. In this case, the effect is enhanced as α is reduced. Therefore, it is possible to reduce the load on the capacitor caused by the voltage difference when switching from discharging to charging. That is, the greater the voltage difference, the higher the voltage applied to the capacitor at a stretch, and a greater physical load is applied to the capacitor element. According to the above configuration, such a load can be reduced. Thereby, when charging / discharging is repeated as in the above configuration, the capacitor can be protected.

  The said structure can be grasped | ascertained as the following technical ideas.

(1) a first power supply circuit that generates DC power for driving a motor from AC power;
An inverter circuit for driving a motor by converting DC power supplied from the first power supply circuit into drive power;
A second power supply circuit for generating DC power for driving the control circuit from the AC power;
A control circuit driven by DC power supplied from the second power supply circuit;
A motor control system that controls the rotation of the motor by controlling the inverter circuit by the control circuit,
The first power supply circuit has a plurality of first power paths for supplying DC power for driving the motor to the inverter circuit, and collects regenerative power during motor regeneration in the plurality of first power paths. A possible capacitor and a first opening / closing means for opening / closing the connection between the capacitor and the inverter circuit,
A connection path is connected to each of the plurality of first power paths, and each of the second power paths outputs the DC power for driving the control circuit in the second power supply circuit via the plurality of connection paths. 1 power path is connected,
The plurality of connection paths are provided with second opening / closing means for opening and closing each of the connection paths,
In a motor regeneration period in which regeneration of the motor is performed, the first opening / closing means of any one of the plurality of first power paths is closed and the first opening / closing means of the other first power path is The first opening / closing means is opened, the second opening / closing means of the connecting path connected to the closed first power path is opened, and the first opening / closing means is connected to the opened first power path. Opening and closing control means for closing the second opening and closing means of the connecting path,
Similarly, in the motor regeneration period, switching of the open / close state is performed for the plurality of first opening / closing means provided in the plurality of first power paths and the plurality of second opening / closing means provided in the plurality of connection paths, respectively. Switching means to
During the motor regeneration period, the storage amount of the capacitor that is collecting regenerative power in the first power supply circuit and the storage amount of the capacitor that is supplying power to the second power supply circuit are detected. Detection means;
With
The switching means is based on a result of a relative comparison between the charged amount of the capacitor that is supplying power and the charged amount of the capacitor that is supplying power. A motor control system for switching an open / close state of an opening / closing means.

  DESCRIPTION OF SYMBOLS 11 ... Motor, 12 ... Inverter circuit, 13 ... Motor power supply circuit (first power supply circuit), 14 ... Control circuit (opening / closing control means, switching means, determination means), 15 ... Control power supply circuit (second power supply circuit), 21 ... AC power supply, 24, 25 ... Power path (first power path), 31, 32 ... Switch (first opening / closing means), 41 ... Power switch, 43 ... Power path (second power path), 46, 48 ... Power Route (connection route), 47, 49... Switch (second opening / closing means).

Claims (4)

A first power supply circuit that generates DC power for driving the motor from AC power;
An inverter circuit for driving a motor by converting DC power supplied from the first power supply circuit into drive power;
A second power supply circuit for generating DC power for driving the control circuit from the AC power;
A control circuit driven by DC power supplied from the second power supply circuit;
A motor control system that controls the rotation of the motor by controlling the inverter circuit by the control circuit,
The first power supply circuit has a plurality of first power paths for supplying DC power for driving the motor to the inverter circuit, and collects regenerative power during motor regeneration in the plurality of first power paths. A possible capacitor and a first opening / closing means for opening / closing the connection between the capacitor and the inverter circuit,
A connection path is connected to each of the plurality of first power paths, and each of the second power paths outputs the DC power for driving the control circuit in the second power supply circuit via the plurality of connection paths. 1 power path is connected,
The plurality of connection paths are provided with second opening / closing means for opening and closing each of the connection paths,
In a motor regeneration period in which regeneration of the motor is performed, the first opening / closing means of any one of the plurality of first power paths is closed and the first opening / closing means of the other first power path is The first opening / closing means is opened, the second opening / closing means of the connecting path connected to the closed first power path is opened, and the first opening / closing means is connected to the opened first power path. Opening and closing control means for closing the second opening and closing means of the connecting path,
Similarly, in the motor regeneration period, switching of the open / close state is performed for the plurality of first opening / closing means provided in the plurality of first power paths and the plurality of second opening / closing means provided in the plurality of connection paths, respectively. Switching means to
A motor control system comprising: In the motor regeneration period, it is determined whether or not the storage amount has reached a predetermined amount with respect to a power collecting capacitor that is collecting regenerative power among the plurality of capacitors provided in the plurality of first power paths. Determination means to perform,
The switching means stops the recovery of regenerative power and recovers the recovered power for the recovering capacitor when the determining means determines that the amount of power stored in the recovering capacitor has reached a predetermined amount. 2. The motor control system according to claim 1, wherein switching of the open / close state of the first opening / closing means and the second opening / closing means is performed in order to start supply to the second power supply circuit side. The second power supply circuit has a power switch that cuts off the supply of the AC power from an AC power supply,
The motor control system according to claim 1, further comprising means for opening the power switch during the motor regeneration period. The second power supply circuit is configured to supply power to the control circuit side by supplying the AC power from an AC power supply during the motor regeneration period,
In the motor regeneration period, the power is being supplied among the capacitor that is recovering regenerative power in the first power supply circuit and the capacitor that is supplying power to the second power supply circuit. Means for detecting the amount of electricity stored in the capacitor,
The switching means switches, when the stored amount of the capacitor being supplied with power is reduced to zero or near zero, the capacitor whose stored amount is reduced to zero or near zero is switched to the regenerative power recovery capacitor. Therefore, the motor control system according to claim 1, wherein switching of an open / close state of the first opening / closing means and the second opening / closing means is performed.

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