JP6513293B1 - Motor drive system and inverter device - Google Patents

Abstract

The motor drive system (5) includes a plurality of inverter devices (3a) to (3n) connected in parallel with each other to the DC bus (2). Each inverter device (3) is connected in parallel to a power conversion circuit (31) for converting direct current power to alternating current power, a voltage detection circuit (32) for detecting direct current voltage (Vdc), and a power conversion circuit (31). Regeneration circuit (34) having a smoothing capacitor (33), a resistor (341) and a semiconductor switch element (342), and a state determination circuit (35) for determining whether the power conversion circuit (31) is in a regeneration state. And a regeneration control circuit (36) for controlling the semiconductor switch element (342) to the conductive state or the cut-off state based on the determination result by the state determination circuit (35) and the comparison result of the DC voltage and the determination threshold.

Description

  The present invention relates to an inverter device that converts direct current power to alternating current power to drive a motor, and a motor drive system including a plurality of such inverter devices.

  When the motor decelerates or stops, the motor operates as a generator. The power generated by the motor is called regenerative power. In a motor drive system including a plurality of inverter devices connected in parallel to a common DC bus, each inverter device includes a voltage detector for detecting a DC voltage and a regeneration circuit that consumes regenerative power. . The regenerative circuit operates based on the detection value of the voltage detector, and the regenerative power is consumed by the regenerative circuit. In addition, it is known that the detection value of a voltage detector produces dispersion | variation between each inverter apparatus.

  In this type of motor drive system, in Patent Document 1 below, information concerning regeneration such as regenerative load factor data, regenerative transistor state data, and bus voltage data is mutually transmitted between a plurality of component devices via a communication interface. Shared technology is disclosed. In Patent Document 1, the regenerative circuit of the inverter device included in the component that has the smallest regenerative load factor data is controlled to be on. According to Patent Document 1, it is possible to avoid the concentration of regenerative power consumption in one inverter device, but it is necessary to share information between the inverter devices.

  In Patent Document 2 below, each inverter device calculates a regenerative load factor, changes the on voltage level based on the calculated regenerative load factor, and based on the changed on voltage level, the regenerative circuit generates regenerative power. Technologies to consume are disclosed. In the technology of Patent Document 2, unlike Patent Document 1, it is possible to consume regenerative power without using a communication means. Thereby, in the motor drive system of patent document 2, it is not necessary to share information between several inverter apparatuses, and simplification of system configuration is attained.

International Publication No. 2001/002918 JP, 2010-110139, A

  However, in the motor drive system of Patent Document 2, there is no guarantee that the inverter device for driving the motor generating regenerative power consumes the regenerative power. Because, due to the variation of the detection value of the voltage detector, the inverter device having the voltage detector that outputs the largest detection value first consumes regenerative power, but the motor of the inverter device first consumes regenerative power, This is because the regeneration operation is not necessarily performed. In Patent Document 2, the voltage detector that outputs the largest detected value always outputs the largest detected value regardless of the change of the on voltage level. For this reason, the inverter apparatus which consumes regenerative electric power first concentrated on the specific inverter apparatus.

  The present invention has been made in view of the above, and a motor that can avoid concentration of inverter devices that consume regenerative power to a specific inverter device without sharing information among the inverter devices. The purpose is to obtain a drive system.

  In order to solve the problems described above and achieve the object, the present invention converts a DC power supplied via a DC bus having a high potential side conductor and a low potential side conductor into AC power to drive a motor. A motor drive system is provided with a plurality of inverter devices, and the plurality of inverter devices are connected in parallel to a DC bus. Each inverter device includes a power conversion circuit that converts direct current power to alternating current power, a voltage detection circuit that detects a direct current voltage applied to the power conversion circuit, a smoothing capacitor connected in parallel to the power conversion circuit, A regenerative circuit in which the resistor and the semiconductor switch element are connected and the resistor and the semiconductor switch element are connected between the high potential side conductor and the low potential side conductor, whether the power conversion circuit is in a regenerative state or not And a regeneration control circuit for controlling the semiconductor switch element of the regeneration circuit to a conductive state or a cut-off state based on the determination result by the state determination circuit and the comparison result of the DC voltage and the determination threshold.

  ADVANTAGE OF THE INVENTION According to this invention, it is effective in the ability to avoid that the inverter apparatus which consumes regenerated electric power concentrates on a specific inverter apparatus, without sharing information between each inverter apparatus.

The block diagram containing the motor drive system provided with the several inverter apparatus which concerns on Embodiment 1. Block diagram showing a detailed configuration of the inverter device in the first embodiment Block diagram showing a detailed configuration of the power conversion circuit in the first embodiment A circuit diagram showing a configuration example of the switching circuit shown in FIG. 3 Block diagram showing a detailed configuration of the regeneration control circuit in the first embodiment A first diagram to be used for explaining the operation of the motor drive system according to the first embodiment A second diagram serving to explain the operation of the motor drive system according to the first embodiment. A third diagram for explaining the operation of the motor drive system according to the first embodiment. Block diagram showing a configuration of a modification of the regeneration control circuit in the first embodiment Block diagram showing a detailed configuration of the regeneration control circuit in the second embodiment Block diagram showing a detailed configuration of a regeneration control signal mask unit in the second embodiment A diagram provided for explaining the operation of the regeneration control circuit according to the second embodiment Block diagram showing a configuration of a modification of the regeneration control signal mask unit in the second embodiment Block diagram showing a detailed configuration of the regeneration control circuit in the third embodiment Block diagram showing a detailed configuration of a regeneration control signal mask unit in the third embodiment A figure serving to explain an operation of a regeneration control circuit according to a third embodiment Block diagram showing a configuration of a modification of the regeneration control signal mask unit in the third embodiment Block diagram showing a detailed configuration of the regeneration control circuit in the fourth embodiment Block diagram showing a detailed configuration of a regeneration control signal mask unit in the fourth embodiment

  Hereinafter, a motor drive system and an inverter device according to an embodiment of the present invention will be described in detail with reference to the attached drawings. The present invention is not limited by the following embodiments. In the attached drawings, blocks, circuits or signals given the same name have the same function. In the following description, although the motor is exemplified as a three-phase motor, a motor other than the three-phase motor may be used. Further, the semiconductor device described in the drawings is an example, and semiconductor switch devices of other symbols may be used. Also, in the following description, physical connection and electrical connection are simply referred to as “connection” without distinction.

Embodiment 1
FIG. 1 is a configuration diagram including a motor drive system 5 provided with a plurality of inverter devices 3a to 3n according to the first embodiment. The motor drive system 5 has inverter devices 3a to 3n. In FIG. 1, the power supply unit 1 is a power supply source that supplies power to the motor drive system 5. The motors 4 a to 4 n are drive targets of the motor drive system 5. Inverter devices 3a to 3n are examples of a plurality of inverter devices. The individual configurations of the inverter devices 3a to 3n are the same. For this reason, when showing inverter apparatus 3a-3n without a code | symbol, it calls "inverter apparatus 3". Motors 4a-4n are examples of a plurality of motors. The individual configurations of the motors 4a to 4n are identical. For this reason, when showing motor 4a-4n without a code | symbol, it calls "motor 4".

  The DC bus 2 has a high potential side conductor 2a and a low potential side conductor 2b. Inverter device 3 a is connected to DC bus 2. Inverter device 3 a constitutes motor drive system 5 together with other inverter devices 3 b to 3 n connected to DC bus 2. The power supply unit 1 supplies DC power to the inverter devices 3 a to 3 n via the DC bus 2.

  The inverter device 3 converts DC power into AC power of any size and frequency. AC power is supplied to the motor 4 from the inverter device 3. The motor 4 is driven by the AC power generated by the inverter device 3. The inverter devices 3a to 3n are connected to the DC bus 2 in parallel with each other. The motor 4 driven by one inverter device 3 is uniquely determined. In the example of FIG. 1, the inverter device 3a drives the motor 4a, the inverter device 3b drives the motor 4b, and the inverter device 3n drives the motor 4n.

  A rotational position detection circuit (not shown) provided in the motor 4 detects the rotational position of the motor 4 and outputs it to the inverter device 3 as position information θ. Position information θ is a generic name of position information θa to θn. Position information θa is output from motor 4a to inverter device 3a. Position information θb is output from motor 4b to inverter device 3b. The position information θn is output from the motor 4n to the inverter 3n. As a rotational position detection circuit, a resolver or an encoder is exemplified.

  FIG. 2 is a block diagram showing a detailed configuration of inverter device 3 in the first embodiment. As shown in FIG. 2, inverter device 3 according to the first embodiment includes power conversion circuit 31, voltage detection circuit 32, smoothing capacitor 33, regeneration circuit 34, state determination circuit 35, and regeneration control circuit 36. Have.

  Power conversion circuit 31, voltage detection circuit 32, smoothing capacitor 33 and regeneration circuit 34 are connected in parallel to DC bus 2.

  Power conversion circuit 31 converts DC power supplied from DC bus 2 into AC power. The motor 4 is driven by the AC power converted by the power conversion circuit 31. The details of the power conversion circuit 31 will be described later.

  The voltage detection circuit 32 detects a DC voltage Vdc applied to the power conversion circuit 31. The DC voltage Vdc detected by the voltage detection circuit 32 is output to the power conversion circuit 31 and the regeneration control circuit 36. As an example of the voltage detection circuit 32, a circuit in which a high resistance first resistor and a low resistance second resistor are connected in series between the high potential side conductor 2a and the low potential side conductor 2b is illustrated. Be done. In this circuit configuration, the voltage across the second resistor is measured, and the measured value is used as the DC voltage Vdc. The DC voltage Vdc output from the voltage detection circuit 32 may be converted into a digital value in the voltage detection circuit 32, or converted into a digital value by the power conversion circuit 31 and the regeneration control circuit 36 of the transmission destination. It is also good.

  The smoothing capacitor 33 equalizes the voltage of the DC power supplied from the DC bus 2. The smoothing capacitor 33 also temporarily stores the regenerative power transmitted from the motor 4.

  The regenerative circuit 34 has a series circuit 34a in which a resistor 341 and a semiconductor switch element 342 are connected in series. Although FIG. 2 shows a configuration in which the resistor 341 is connected to the high potential side and the semiconductor switch element 342 is connected to the low potential side, the present invention is not limited to this configuration. The semiconductor switch element 342 may be connected to the high potential side, and the resistor 341 may be connected to the low potential side.

  The state determination circuit 35 generates a state determination signal St based on the current information Io output from the power conversion circuit 31 and the position information θ output from the motor 4. The state determination signal St is a signal indicating whether the power conversion circuit 31 is in the regenerative state. The current information Io is current information of at least one phase of the motor current flowing to the motor 4.

  Here, in the present specification, a state in which power is transmitted from the motor 4 to the inverter device 3 is referred to as “the inverter device 3 is in the“ regeneration state ”” for simplification of the description. Further, all cases where the inverter device 3 is not in the regeneration state are referred to as "the inverter device 3 is in the" powering state ". In addition, when there is no exchange of electric power between the inverter apparatus 3 and the motor 4, it is included in a "powering state." Further, the power to the motor 4 transmitted from the inverter device 3 in the power running state is referred to as "power running power".

  The state determination signal St generated by the state determination circuit 35 is output to the regeneration control circuit 36.

  The state determination signal St is obtained based on the product of the torque of the motor 4 obtained from the position information θ and the current information Io and the rotational angular velocity of the motor 4 obtained from the current information Io. Needless to say, other methods may be used.

  In the following description, the state of the state determination signal St when the power conversion circuit 31 is in the regenerative state is referred to as “H level”. Further, the state of the state determination signal St when the power conversion circuit 31 is not in the regeneration state is referred to as “L level”.

  The regeneration control circuit 36 generates a control signal SW based on the DC voltage Vdc and the state determination signal St. The control signal SW is output to the regeneration circuit 34. The control signal SW controls the semiconductor switch element 342 in the regeneration circuit 34 to be in the conductive state or in the cut-off state. Here, the state of the control signal SW for turning on the semiconductor switch element 342 is referred to as “on level”. Further, the state of the control signal SW which brings the semiconductor switch element 342 into the cutoff state is referred to as the "off level".

  When the control signal SW is at the on level, a current flows in the resistor 341. On the other hand, when the control signal SW is at the off level, no current flows in the resistor 341. Details of the regeneration control circuit 36 will be described later.

  FIG. 3 is a block diagram showing a detailed configuration of power conversion circuit 31 in the first embodiment. FIG. 4 is a circuit diagram showing a configuration example of the switching circuit 311 shown in FIG.

  The power conversion circuit 31 in the first embodiment has a switching circuit 311, a switching circuit control circuit 312, and a current detection circuit 313, as shown in FIG.

  As shown in FIG. 4, DC power is supplied to the switching circuit 311 from the DC bus 2. The switching circuit 311 has three sets of two semiconductor switch elements 311a and 311a connected in series between the high potential side conductor 2a and the low potential side conductor 2b. The upper semiconductor switch element 311a is also referred to as an upper arm, and the lower semiconductor switch element 311a is also referred to as a lower arm. A set in which two semiconductor switch elements 311a are connected in series is also referred to as an upper and lower arm. That is, the switching circuit 311 has a configuration in which three sets of upper and lower arms in which two semiconductor switching elements 311a are connected in series are connected in parallel.

  A connection point 311 c between the semiconductor switch element 311 a of the upper arm and the semiconductor switch element 311 a of the lower arm serves as an output end for supplying AC power for driving the motor 4. The connection point 311c of the upper and lower arms is also called a middle point. A diode 311d is connected in antiparallel to the respective semiconductor switch elements 311a constituting the three sets of upper and lower arms.

  The semiconductor switch elements 311 a in the upper and lower arms switch the paths through which DC power flows based on the drive signal Gt from the switching circuit control circuit 312 to generate three-phase AC power. The drive signal Gt is a signal for controlling the conduction state of each semiconductor switch element 311a. In FIG. 3, the six drive signals Gt are collectively referred to as "Gt".

  When the motor 4 decelerates or stops, the regenerative power from the motor 4 is supplied to the smoothing capacitor 33 via the diode 311 d of the switching circuit 311.

  The switching circuit control circuit 312 generates a drive signal Gt based on the command value Cs, the DC voltage Vdc, and the position information θ. The drive signal Gt is generated using known PWM (Pulse Width Modulation) control. Various command values Cs may be used depending on the application. As the command value Cs, a desired rotational speed including desired time change information of the motor 4, a desired torque, or a desired movement distance is exemplified. Depending on the application, a plurality of command values combining some of these may be used.

  The current detection circuit 313 is installed on a conductor connecting between the connection point 311 c of the upper and lower arms and the motor 4. The current detection circuit 313 detects and outputs current information Io of at least one phase of the output of the switching circuit 311. There are various detection methods of the current information Io. One example of the detection method is a method of measuring a magnetic field generated in a conductor connecting between the middle point of the upper and lower arms and the motor 4. In another example of the detection method, a resistor having an extremely small resistance value is inserted between the connection point 311 c of the upper and lower arms and the conductor connecting between the motor 4 and the voltage across the resistor. There is a way to measure.

  FIG. 5 is a block diagram showing a detailed configuration of the regeneration control circuit 36 in the first embodiment. As shown in FIG. 5, the regeneration control circuit 36 according to the first embodiment includes a first storage unit 361, a second storage unit 362, a third storage unit 363, a switching unit 364 and a first comparison unit 365. , A second comparison unit 366, a regeneration control signal generation unit 367, and a regeneration control signal amplification unit 368.

  The first storage unit 361 stores a predetermined first threshold value Vth1. The first threshold value Vth1 is a determination threshold value of the DC voltage Vdc at which the regeneration circuit 34 starts conducting when the power conversion circuit 31 is in the regeneration state. The first threshold Vth1 is output to the switching unit 364.

  The second storage unit 362 stores a predetermined second threshold value Vth2. The second threshold value Vth2 is a determination threshold value of the DC voltage Vdc at which the regeneration circuit 34 starts the conduction state when the power conversion circuit 31 is not in the regeneration state, that is, in the powering state. The second threshold Vth2 is output to the switching unit 364.

  The third storage unit 363 stores a predetermined third threshold Vth3. The third threshold value Vth3 is a determination threshold value of the DC voltage Vdc at which the regeneration circuit 34 stops conducting. The third threshold Vth3 is output to the second comparison unit 366.

  The third threshold Vth3 is a value smaller than the first threshold Vth1. Also, the first threshold Vth1 is a value smaller than the second threshold Vth2.

  When state determination signal St is at the H level, switching unit 364 outputs first threshold value Vth1 to first comparison unit 365 as regeneration start threshold value Vto. On the other hand, when the state determination signal St is L level, the switching unit 364 outputs the second threshold value Vth2 to the first comparison unit 365 as the regeneration start threshold value Vto. The regeneration start threshold Vto is output to the first comparison unit 365.

  The first comparison unit 365 compares the DC voltage Vdc with the regeneration start threshold Vto. When the DC voltage Vdc is equal to or higher than the regeneration start threshold Vto, the first comparison unit 365 outputs a signal Von indicating significance to the regeneration control signal generation unit 367. The signal Von is a signal indicating the comparison result of the DC voltage Vdc and the regeneration start threshold Vto.

  Here, the case where the signal Von is significant is referred to as "one level". Also, the case where the signal Von is not significant is referred to as "0 level". That is, the state in which the signal Von is “1 level” is the state of Vdc ≧ Vto, and the state in which the signal Von is “0 level” is the state of Vdc <Vto. Here, the state of Vdc = Vto is included in the “1 level”, but the state of Vdc = Vto may be included in the “0 level”.

  The second comparison unit 366 compares the DC voltage Vdc with the third threshold Vth3. When the DC voltage Vdc is equal to or less than the third threshold value Vth3, the second comparison unit 366 outputs a signal Voff indicating significance to the regeneration control signal generation unit 367. The signal Voff is a signal indicating the comparison result of the DC voltage Vdc and the third threshold Vth3.

  Here, the case where the signal Voff is significant is referred to as "one level", and the case where the signal Voff is not significant is referred to as a "zero level". That is, the state in which the signal Voff is “1 level” is the state of Vdc ≦ Vth3, and the state in which the signal Voff is “0 level” is the state of Vdc> Vth3. Here, the state of Vdc = Vth3 is included in the “1 level”, but the state of Vdc = Vth3 may be included in the “0 level”.

  The regeneration control signal generation unit 367 generates a signal So based on the signal Von and the signal Voff. Signal So is output to regeneration control signal amplification unit 368. The regeneration control signal generation unit 367 sets the signal So to the “on level” at the timing when the signal Von changes from the “0 level” to the “1 level”. Immediately before the signal Von changes from “0 level” to “1 level”, the second comparing section 366 outputs a signal Voff indicating significance, so the signal So is “off level”. Therefore, at the timing when the signal Von changes from “0 level” to “1 level”, the signal So becomes “on level”.

  Further, the regeneration control signal generation unit 367 sets the signal So to the “off level” at the timing when the signal Voff changes from the “0 level” to the “1 level”. Immediately before the signal Voff changes from “0 level” to “1 level”, the first comparison unit 365 outputs a signal Von indicating significance, so the signal So is “on level”. Therefore, at the timing when the signal Voff changes from “0 level” to “1 level”, the signal So becomes “off level”.

  The meaning of the on level of the signal So is the same as the meaning of the on level of the control signal SW described above. Further, the meaning of the off level of the signal So is the same as the meaning of the off level of the control signal SW described above. That is, the signal level for turning on the semiconductor switching element 342 is called "on level", and the signal level for turning off the semiconductor switching element 342 is called "off level".

  Regeneration control signal amplification unit 368 amplifies signal So to a voltage amplitude or current amount that can drive semiconductor switch element 342. The amplified signal is output to the regeneration circuit 34 as the control signal SW described above.

  Next, the operation of the motor drive system according to the first embodiment will be described with reference to the drawings in FIGS. 1 to 8 as appropriate. FIG. 6 is a first diagram for explaining the operation of the motor drive system 5 according to the first embodiment. FIG. 7 is a second diagram for explaining the operation of the motor drive system 5 according to the first embodiment. FIG. 8 is a third diagram for describing the operation of the motor drive system 5 according to the first embodiment.

  If the sum of the regenerative power of the inverter device 3 in the regenerative state is equal to or smaller than the sum of the powering power of the inverter device 3 in the powering state, the regenerative power is consumed as the powering power and the DC voltage Vdc Does not rise. On the contrary, when the sum total of the regenerative power of the inverter device 3 in the regeneration state is larger than the sum of the power running power of the inverter device 3 in the power running state, the DC voltage Vdc rises.

  The rise of the DC voltage Vdc occurs even when there is only one inverter device 3a in the regenerative state. As a specific example, inverter device 3a is in a regenerative state, all other inverter devices 3, namely, inverter devices 3b to 3n are in a powering state, and the regenerative power of inverter device 3a is the powering power of inverter devices 3b to 3n. Consider the case where it is larger than the sum of. In this case, the surplus regenerative power obtained by subtracting the sum of the powering power from the regenerative power is a positive value. Thus, the surplus regenerative power is stored in all the smoothing capacitors 33 present in the motor drive system 5. As a result, the DC voltage Vdc rises. At this time, the state determination signal St in the inverter device 3a becomes H level. On the other hand, the state determination signal St in the inverter devices 3b to 3n becomes L level.

  When the DC voltage Vdc rises and the DC voltage Vdc becomes equal to or higher than the first threshold value Vth1, the control signal SW in the inverter device 3a in the regenerative state becomes the on level. As a result, the semiconductor switch element 342 of the regeneration circuit 34 in the inverter device 3a becomes conductive.

  When the semiconductor switch element 342 of the regeneration circuit 34 is turned on, the electric charge stored in the smoothing capacitor 33 is discharged, so the DC voltage Vdc decreases. When the DC voltage Vdc decreases and becomes equal to or less than the third threshold value Vth3, the control signal SW in the inverter device 3a changes to the off level.

  The control signals SW in the inverter devices 3b to 3n become the on level when the DC voltage Vdc becomes equal to or higher than the second threshold Vth2, and change to the off level when the DC voltage Vdc becomes equal to or lower than the third threshold Vth3.

  Next, a more detailed operation example will be described with reference to FIG. In FIG. 6, one inverter device 3a of the motor drive system 5 is in the regenerative state, the remaining inverter devices 3b to 3n are in the powering state, and the regenerative power of the inverter device 3a is the inverter devices 3b to 3n. The operation waveform in the case where it is larger than the sum total of the power running power of is shown.

  The upper part of FIG. 6 schematically shows a change in DC voltage Vdc when regenerative power is generated in a period from time ts to time te. In the middle part of FIG. 6, the change of the control signal SW of the inverter device 3a in the regenerative state is shown. The lower part of FIG. 6 shows changes in the control signal SW of the inverter devices 3b to 3n in the power running state.

  At time ton1, the DC voltage Vdc reaches the first threshold Vth1. At this time, the control signal SW of the inverter device 3a changes from L level to H level. However, the semiconductor switching element 342 is actually brought into conduction from the point P0 at which the DC voltage Vdc is slightly higher than the first threshold Vth1. This is because a time delay occurs when the semiconductor switch element 342 becomes conductive with respect to time ton1 which is the output time of the control signal SW.

  When the semiconductor switching element 342 conducts, the power stored in the smoothing capacitor 33 is consumed by the resistor 341. As a result, the DC voltage Vdc drops from the point P0.

  At time toff1 when the DC voltage Vdc becomes lower than or equal to the third threshold Vth3, the control signal SW of the inverter device 3a changes from the H level to the L level. However, the fact that the semiconductor switching element 342 is cut off actually is from the point P1 where the DC voltage Vdc is slightly lower than the third threshold Vth3. This is because a time delay occurs when the semiconductor switch element 342 is turned off with respect to time toff1 which is the output time of the control signal SW.

  When the semiconductor switch element 342 is shut off, the regenerative power is stored in the smoothing capacitor 33. As a result, the DC voltage Vdc rises again.

  After time toff1, the control signal SW of the inverter device 3a in the regenerative state changes as illustrated at time ton2, time toff2, time ton3, and time toff3. In accordance with these changes, as shown in FIG. 6, the DC voltage Vdc also changes to point P2, point P3, point P4 and point P5.

  The control that consumes the surplus regenerative power ends at time te. After time te, the direct current voltage Vdc gradually drops due to a not-shown discharge resistor provided in the smoothing capacitor 33 or a not-shown resistor existing in the voltage detection circuit 32. Also, after time te, the control signal SW of the inverter device 3a in the regenerative state continues to be at the L level. On the other hand, in the control signals SW of the inverter devices 3b to 3n in the power running state, the DC voltage Vdc never exceeds the second threshold Vth2 even once. Therefore, control signals SW of inverter devices 3b to 3n maintain L level from time ts to time te.

  Next, an operation example different from that of FIG. 6 will be described with reference to FIGS. 7 and 8. In FIGS. 7 and 8, two inverter devices 3a and 3b of the motor drive system 5 are in the regenerative state, and the remaining inverter devices 3c to 3n are in the powering state, and regeneration of the inverter devices 3a and 3b. The operation | movement waveform in case the sum total of electric power is larger than the sum total of the power running power of inverter apparatus 3c-3n is shown. In FIG. 1, the inverter device 3 c is not shown.

  Changes in DC voltage Vdc when regenerative electric power is generated are schematically shown in the upper part of each of FIGS. 7 and 8 in a period from time ts to time te. 7 and 8 show changes in the control signal SW of the inverter device 3a in the regenerative state. Changes in the control signal SW of the inverter device 3b in the regenerative state are shown in the middle and lower portions of FIGS. 7 and 8, respectively. Changes in the control signal SW of the inverter devices 3c to 3n in the power running state are shown in the lower part of each of FIGS. 7 and 8.

  The same value is stored as the first threshold Vth1 of the inverter device 3a and the first threshold Vth1 of the inverter device 3b. However, the DC voltage at which the first comparison unit 365 of the inverter device 3a becomes "1 level" due to the variation of the electronic components between the voltage detection circuit 32 of the inverter device 3a and the voltage detection circuit 32 of the inverter device 3b. The true value of Vdc and the true value of the DC voltage Vdc at which the first comparison unit 365 of the inverter device 3b is at "1" level are usually different. Therefore, in the example of FIGS. 7 and 8, the apparent threshold value of the first threshold value Vth1 at which the first comparing unit 365 of the inverter device 3a becomes “1 level” is “Vth1_a”, and the first comparison of the inverter device 3b is performed. The apparent threshold value of the first threshold value Vth1 at which the part 365 becomes “1 level” is “Vth1_b”. In the examples of FIGS. 7 and 8, it is assumed that the relationship of Vth1_a <Vth1_b exists between Vth1_a and Vth1_b. Therefore, the relationship including Vth3 and Vth2 is Vth3 <Vth1_a <Vth1_b <Vth2.

  The difference between FIG. 7 and FIG. 8 is whether or not the signal level of the control signal SW of the inverter device 3b in the regenerative state changes. In other words, whether or not the regenerative circuit 34 of the inverter device 3b in the regenerative state consumes regenerative power. FIG. 7 shows an example of the case where the regenerative circuit 34 of the inverter device 3b does not consume the regenerative power, and FIG. 8 shows an example of the case where the regenerative circuit 34 of the inverter device 3b consumes the regenerative power. Such differences occur at the positions of the point P0, the point P2 and the point P4, which are operating points at which the DC voltage Vdc reaches the top. As shown in FIG. 7, when the points P0, P2 and P4 are between Vth1_a and Vth1_b, the control signal SW of the inverter device 3b never becomes H level. Therefore, the example of FIG. 7 performs the same operation as that of FIG. On the other hand, if the points P0, P2 and P4 are above Vth1_b as shown in FIG. 8, the control signal SW of the inverter device 3b may also be H level, and the operation is different from that of FIG.

  In the case of FIG. 8, the time ton1b, the time ton2b and the time ton3b when the control signal SW of the inverter device 3b changes from L level to H level, the time ton1a when the control signal SW of the inverter device 3a changes from L level to H level, It is later than each of time ton2a and time ton3a. As a result, the time when the semiconductor switch element 342 of the inverter device 3b becomes conductive is delayed from the time when the semiconductor switch element 342 of the inverter device 3a is conductive. As a result, the electric power stored in all the smoothing capacitors 33 in the motor drive system 5 consumes the regenerated electric power only by the resistor 341 of the inverter device 3a in the following period.

· From the time ton1a when the semiconductor switch element 342 of the inverter device 3a becomes conductive to the time ton1b when the semiconductor switch element 342 of the inverter device 3b becomes conductive · The semiconductor switch element 342 of the inverter device 3a becomes conductive From time ton2a to time ton2b when the semiconductor switching device 342 of the inverter device 3b becomes conductive state · From the time ton3a when the semiconductor switching device 342 of the inverter device 3a becomes conductive state, the semiconductor switching device 342 of the inverter device 3b becomes conductive Until time ton3b to be in state

  On the other hand, in the following period, the electric power stored in all the smoothing capacitors 33 in the motor drive system 5 consumes the regenerative electric power in both the resistor 341 of the inverter device 3a and the resistor 341 of the inverter device 3b.

・ From time ton1b when semiconductor switch element 342 of inverter device 3b becomes conductive state to time toff1 when semiconductor switch element 342 of inverter device 3a and semiconductor switch element 342 of inverter device 3b become cut off state ・ Inverter device 3b From time ton2b when the semiconductor switch element 342 of the semiconductor switch 342 becomes conductive to time toff2 when both the semiconductor switch element 342 of the inverter device 3a and the semiconductor switch element 342 of the inverter device 3b become cut off · semiconductor switch element of the inverter device 3b From time ton 3 b when the conduction state 342 is in a conductive state to time t off 3 when both the semiconductor switching element 342 of the inverter device 3 a and the semiconductor switching element 342 of the inverter device 3 b become a disconnection state

  Then, from time toff1 and time toff2 at which both semiconductor switch element 342 of inverter device 3a and semiconductor switch element 342 of inverter device 3b are in the disconnected state, semiconductor switch element 342 of inverter device 3a becomes conductive again. The semiconductor switching device 342 of the inverter device 3a and the semiconductor switching device 342 of the inverter device 3b are both turned off during and until each of the times ton 3a. In this case, the surplus regenerative power is stored in all the smoothing capacitors 33 present in the motor drive system 5.

  Further, in the control signals SW of the inverter devices 3c to 3n in the power running state, the DC voltage Vdc never exceeds the second threshold Vth2 even once. Therefore, the L level is maintained from time ts to time te.

  Further, due to the variation between the voltage detection circuit 32 of the inverter device 3a and the voltage detection circuit 32 of the inverter device 3b, the detection result of the voltage detection circuit 32 and the comparison result of the third threshold Vth3 May differ. Due to this difference, the time when the control signal SW of the inverter device 3a changes from H level to L level differs from the time when the control signal SW of the inverter device 3b changes from H level to L level. As a result, the time when the semiconductor switch element 342 of the inverter device 3a is in the cut-off state is different from the time when the semiconductor switch element 342 of the inverter device 3b is in the cut-off state. The operation in the case where the shutoff time of the semiconductor switch element 342 of the inverter device 3a is different from the shutoff time of the semiconductor switch element 342 of the inverter device 3b can be easily inferred from the operation in the conductive state. For this reason, the explanation here is omitted. Further, as a matter of course, the variation regarding the second threshold value Vth2 may occur, but it is not directly related to the gist of the present embodiment, so the description here will be omitted.

  In the configuration of the first embodiment, the power supply unit 1 is exemplified by a full-wave rectifier using a diode, a one-pulse regenerative converter, or a high power factor converter.

  The switching circuit control circuit 312 and the state determination circuit 35 can be realized by software processing in a microcomputer or a circuit formed in a programmable gate array.

  The switching unit 364, the first comparing unit 365, the second comparing unit 366 and the regeneration control signal generating unit 367 in the regeneration control circuit 36 are software processes in a microcomputer, circuits formed in a programmable gate array, or discretes. It can be realized by a combination of semiconductor elements.

  The first storage unit 361, the second storage unit 362, and the third storage unit 363 in the regeneration control circuit 36 are a storage unit of a microcomputer, a random access memory (RAM) area in a programmable gate array, or a read only memory (ROM). It can be realized by an area or a semiconductor memory.

  The regeneration control signal amplification unit 368 in the regeneration control circuit 36 can realize amplification of voltage or current by hardware using an operational amplifier or a semiconductor element.

  The motor drive system 5 according to the first embodiment is configured as described above and operates as described above. Therefore, the following effects can be obtained.

  The regeneration control circuit 36 determines, based on the determination result of the state determination circuit 35, the determination threshold whether to make the semiconductor switch element 342 of the regeneration circuit 34 conductive or not, the first threshold Vth1 and a value larger than the first threshold Vth1. Switching between the second threshold Vth2 and the second threshold Vth2. As a result, even if the detection value of the voltage detector varies, the generated regenerative power is always consumed by the inverter device 3 in the regenerative state. In the operation of the motor drive system 5, all the inverter devices 3 are not simultaneously brought into the regeneration state or the powering state. As a result, whether it is in the regeneration state or the power running state varies among the inverter devices 3. For this reason, it can be avoided that the regeneration processing is concentrated on the specific inverter device 3. As a result, the life of the inverter device 3 can be extended, and the effect of reducing the cost of equipment renewal can also be obtained.

  Moreover, the thing of the capacity | capacitance according to the capability of the motor 4 which drives the inverter apparatus 3 is installed. For this reason, generation | occurrence | production of the condition that regenerated electric power is consumed can be prevented by the inverter apparatus 3 of the small electric power capacity in a power running state. As a result, the life of the inverter device 3 can be extended, the product manufacturing cost can be reduced, and the update cost can be reduced.

  Further, as described above, the inverter device 3 independently performs the regenerative power consumption operation. For this reason, since it is not necessary to exchange and share the information regarding regeneration between each inverter device 3, a mutual communication function can be omitted. Thus, not only the cost reduction effect of the inverter device 3 alone can be obtained, but also the reduction effect of the installation cost of the entire motor drive system can be obtained.

  Further, as described above, the mutual communication function can be omitted among the plurality of inverter devices 3. As a result, since the number of failure points is reduced, the operation rate of the system can be increased, and the maintenance cost can be reduced.

  Next, a modification of regeneration control circuit 36 according to the first embodiment will be described with reference to FIG. FIG. 9 is a block diagram showing a detailed configuration of a regeneration control circuit 36A in which the configuration of the regeneration control circuit 36 shown in FIG. 5 is modified. As shown in FIG. 9, the regeneration control circuit 36A includes a first storage unit 361, a second storage unit 362, a third storage unit 363, a switching unit 364a, a first comparison unit 365a, and a second comparison unit 366. , A third comparison unit 365b, a regeneration control signal generation unit 367, and a regeneration control signal amplification unit 368.

  The functions of the first storage unit 361, the second storage unit 362, and the third storage unit 363 are the same as or equivalent to those shown in FIG. 5, and redundant description will be omitted. The first threshold Vth1 held in the first storage unit 361 is output to the first comparison unit 365a. The second threshold Vth2 held in the second storage unit 362 is output to the third comparison unit 365b. The third threshold Vth3 held in the third storage unit 363 is output to the second comparison unit 366.

  The first comparison unit 365a compares the DC voltage Vdc with the first threshold Vth1. When the DC voltage Vdc is equal to or higher than the first threshold value Vth1, the first comparison unit 365a outputs a signal Von1 indicating significance to the switching unit 364a. As in the case of the description of FIG. 5, the case where the signal Von1 is significant is referred to as “1 level”, and the case where the signal Von1 is not significant is referred to as “0 level”. The same applies to the signal Von2 and the signal Voff.

  The state in which the signal Von1 is “1 level” is the state of VdcVthVth1, and the state in which the signal Von1 is “0 level” is the state of Vdc <Vth1. Here, the state of Vdc = Vth1 is included in the “1 level”, but the state of Vdc = Vth1 may be included in the “0 level”.

  The third comparison unit 365b compares the DC voltage Vdc with the second threshold Vth2. When the DC voltage Vdc is equal to or higher than the second threshold value Vth2, the third comparison unit 365b outputs a signal Von2 indicating significance to the switching unit 364a. The state in which the signal Von2 is “1 level” is the state of Vdc ≧ Vth2, and the state in which the signal Von2 is “0 level” is the state of Vdc <Vth2. Here, the state of Vdc = Vth2 is included in the “1 level”, but the state of Vdc = Vth2 may be included in the “0 level”.

  The second comparison unit 366 compares the DC voltage Vdc with the third threshold Vth3. When the DC voltage Vdc is equal to or less than the third threshold value Vth3, the second comparison unit 366 outputs a signal Voff indicating significance to the regeneration control signal generation unit 367. The state in which the signal Voff is “1 level” is the state of Vdc ≦ Vth3, and the state in which the signal Voff is “0 level” is the state of Vdc> Vth3. Here, the state of Vdc = Vth3 is included in the “1 level”, but the state of Vdc = Vth3 may be included in the “0 level”.

  When the signals Von1, Von2, and Voff are to be distinguished from one another without a code, the signal Von1 is referred to as a "first signal" and the signal Voff as a "second signal". The signal Von2 is called a "third signal".

  When state determination signal St is at the H level, switching unit 364a outputs signal Von1 as regeneration start timing signal Vto1. On the other hand, when the state determination signal St is at the L level, the switching unit 364a outputs the signal Von2 as the regeneration start timing signal Vto1. The regeneration start timing signal Vto1 is output to the regeneration control signal generation unit 367.

  The regeneration control signal generation unit 367 generates a signal So based on the regeneration start timing signal Vto1 and the signal Voff. Signal So is output to regeneration control signal amplification unit 368. The regeneration control signal generation unit 367 sets the signal So to the “on level” at the timing when the regeneration start timing signal Vto1 changes from the “0 level” to the “1 level”. Further, the regeneration control signal generation unit 367 sets the signal So to the “off level” at the timing when the signal Voff changes from the “0 level” to the “1 level”.

  The meaning of the on level of the signal So is the same as the meaning of the on level of the control signal SW described above. Further, the meaning of the off level of the signal So is the same as the meaning of the off level of the control signal SW described above.

  Regeneration control signal amplification unit 368 amplifies signal So to a voltage amplitude or current amount that can drive semiconductor switch element 342. The amplified signal is output to the regeneration circuit 34 as the control signal SW described above.

  A regeneration control circuit 36A, which is a modification of the regeneration control circuit 36 in the first embodiment, is configured as described above, and outputs a control signal SW that is the same as or equivalent to that of the regeneration control circuit 36 that is a basic configuration. For this reason, the regeneration control circuit 36A which is a modification example has the same or equivalent effect as the regeneration control circuit 36 which is the basic configuration.

Second Embodiment
Embodiment 1 demonstrated the form which the inverter apparatus 3 in a regeneration state consumes regenerated electric power. However, there is a case where it can not be processed only by the inverter device 3 in the regenerative state in a mode in which operation such as control of heavy load drop or sudden stop from high speed rotation state occurs. The case where the processing can not be performed only with the inverter device 3 in the regenerative state is a case where the regenerative power is large and exceeds the steady-state power allowable value of the resistor 341 in the inverter device 3 in the regenerative state. Therefore, in the second and subsequent embodiments, an embodiment suitable for processing regenerative electric power generated from one motor 4 by a plurality of inverter devices 3 will be described.

  FIG. 10 is a block diagram showing a detailed configuration of the regeneration control circuit 36B in the second embodiment. In the configuration of regeneration control circuit 36 of the first embodiment shown in FIG. 5, regeneration control signal mask portion 369 is inserted between regeneration control signal generation portion 367 and regeneration control signal amplification portion 368 in regeneration control circuit 36B. It is done. The other configuration is the same as or equivalent to the configuration of FIG. 5, and the same or equivalent components are denoted by the same reference numerals and redundant description will be omitted.

  FIG. 11 is a block diagram showing a detailed configuration of the regeneration control signal mask unit 369 in the second embodiment. As shown in FIG. 11, the regeneration control signal mask unit 369 according to the second embodiment includes a counting unit 3691, a fourth storage unit 3692, a fifth storage unit 3693, a fourth comparison unit 3694, and a fifth comparison unit. It has 3695, a state holding unit 3696, and a second switching unit 3697.

  The counting unit 3691 counts the on time cumulative time Ton of the signal So output from the regeneration control signal generation unit 367 and the off time cumulative time Toff. Next, the counting unit 3691 calculates the regeneration load rate Rr based on the cumulative time Ton, the cumulative time Toff, and the mask signal G output from the state holding unit 3696 described later. The regenerative load factor Rr is a time ratio when the semiconductor switch element is in the conductive state. The mask signal G is a signal that outputs "1" on the logical operation at the time of the significant state, and outputs "0" on the logical operation at the time of the non-significant state.

  Specifically, the counting unit 3691 performs the calculation represented by the following equation (1) to generate the regenerative load factor Rr.

  Rr = (Ton &! G) / (Ton + Toff) ... (1)

  In the above equation (1), “&” is a binary operator representing a logical product. Also, “! G” means an inverted signal of the mask signal G. The inverted signal of the mask signal G is a signal that means "0" on the logic operation at the time when the mask signal G is significant, and a signal that means "1" on the logic operation when it is not significant. is there.

  The fourth storage unit 3692 stores a fourth threshold Rsp. The fourth threshold Rsp is output to the fourth comparison unit 3694. The fourth threshold Rsp is selected to a value that satisfies the following equation (2).

  Rsp ≦ (Wmax · R) / (Vth1 · Vth1) (2)

  In the above equation (2), “Wmax” is the steady-state power tolerance value of the resistor 341, and “R” is the resistance value of the resistor 341.

  The fifth storage unit 3693 stores a fifth threshold Rst. The fifth threshold Rst is output to the fifth comparison unit 3695. As the fifth threshold Rst, a value satisfying the following equation (3) can be selected. However, in practice, a value less than Rsp / 2 and a value close to 0 is often employed.

  0 <Rst <Rsp (3)

  The fourth comparison unit 3694 compares the regenerative load factor Rr with the fourth threshold Rsp. When the regenerative load factor Rr is equal to or higher than the fourth threshold Rsp, the fourth comparison unit 3694 outputs a signal SP indicating significance to the state holding unit 3696.

  Here, the case where the signal SP is significant is called "one level". Also, the case where the signal SP is not significant is referred to as "0 level". That is, the state in which the signal SP is “1 level” is the state of Rr ≧ Rsp, and the state in which the signal SP is “0 level” is the state of Rr <Rsp. Here, the state of Rr = Rsp is included in the “1 level”, but the state of Rr = Rsp may be included in the “0 level”.

  The fifth comparison unit 3695 compares the regenerative load factor Rr with the fifth threshold Rst. When the regenerative load factor Rr is equal to or less than the fifth threshold Rst, the fifth comparison unit 3695 outputs a signal RS indicating significance to the state holding unit 3696.

  Here, the case where the signal RS is significant is called "one level". Also, the case where the signal RS is not significant is referred to as "0 level". That is, the state in which the signal RS is “1 level” is the state of Rr ≦ Rst, and the state in which the signal RS is “0 level” is the state of Rr> Rst. Here, the state of Rr = Rst is included in the “1 level”, but the state of Rr = Rst may be included in the “0 level”.

  The state holding unit 3696 generates a mask signal G based on the signal SP and the signal RS. The mask signal G is a signal for inhibiting the semiconductor switch element 342 of the regeneration circuit 34 from being in a conductive state. In other words, the mask signal G is a signal that controls the semiconductor switch element 342 of the regeneration circuit 34 to be forcibly shut off. The mask signal G is output to the counting unit 3691 and the second switching unit 3697. The state holding unit 3696 sets the mask signal G to logic 1 at the timing when the signal SP changes from “0 level” to “1 level”. Further, the state holding unit 3696 sets the mask signal G to logic 0 at the timing when the signal RS changes from “0 level” to “1 level”. At timings other than the above, the signal level at that time is maintained.

  The second switching unit 3697 generates a signal Sm based on the signal So output from the regeneration control signal generation unit 367 and the mask signal G. Signal Sm is output to regeneration control signal amplification unit 368. The second switching unit 3697 fixes the signal Sm to the off level during the period when the mask signal G is logic 1 and the on level and the off level of the signal So as they are during the period when the mask signal G is logic 0. Transmit to That is, the second switching unit 3697 passes the signal So to the signal Sm as it is while the mask signal G is at logic 0, and continues to output the off level while the mask signal G is at logic 1.

  Next, the operation of the regeneration control circuit 36B in the second embodiment will be described with reference to the drawings in FIGS. 10 to 12 as appropriate. FIG. 12 is a diagram for explaining the operation of the regeneration control circuit 36B in the second embodiment.

  In the operation description of the second embodiment, one inverter device 3a of the motor drive system 5 is in a regenerative state, the other inverter devices 3b to 3n are in a powering state, and the regenerative power of the inverter device 3a is an inverter. Consider the case where the sum of the power running powers of the devices 3b to 3n is larger.

  The following waveforms are shown in FIG. 12 from the top to the bottom on the same time axis.

(1) DC voltage Vdc
(2) Signal So of inverter device 3a
(3) Regeneration load factor Rr of inverter device 3a
(4) Mask signal G of inverter device 3a
(5) Control signal SW of inverter device 3a
(6) Signals So of other inverter devices 3b to 3n
(7) Regeneration load factor Rr of other inverter devices 3b to 3n
(8) Mask signal G of other inverter devices 3b to 3n
(9) Control signals SW of other inverter devices 3b to 3n

  FIG. 12 (1) schematically shows a change in DC voltage Vdc when regenerative power is generated in a period from time ts to time te. As shown in FIG. 12 (1), when regenerative power occurs, the DC voltage Vdc rises.

  In the inverter device 3a in the regenerative state, when the DC voltage Vdc becomes larger than the first threshold value Vth1, as shown in FIG. 12 (2), the signal So of the inverter device 3a in the regenerative state changes to H level. At this time, current flows in the resistor 341 in the regeneration circuit 34 of the inverter device 3a in the regeneration state.

  The regenerative load factor Rr calculated by the counting unit 3691 of the inverter device 3a in the regenerative state increases as shown in FIG. 12 (3). However, the regenerative load factor Rr has not yet reached the fourth threshold Rsp. For this reason, as shown in FIG. 12 (4), the mask signal G of the inverter device 3a in the regenerative state remains 0. Therefore, as shown in FIG. 12 (5), the control signal SW of the inverter device 3a in the regenerative state has the same waveform as that of the signal So. Thereby, the regeneration circuit 34 of the inverter device 3a in the regeneration state continues the regeneration process. As shown in FIG. 12 (1), the DC voltage Vdc drops toward the third threshold value Vth3 due to the regeneration process by the regeneration circuit 34 of the inverter device 3a in the regeneration state.

  When the DC voltage Vdc becomes smaller than the third threshold value Vth3, as shown in FIG. 12 (2), the signal So of the inverter device 3a in the regenerative state changes to L level, and the regenerative circuit of the inverter device 3a in the regenerative state. The current flowing to the resistor 341 in 34 stops. The regenerative load factor Rr calculated by the counting unit 3691 of the inverter device 3a in the regenerative state decreases as shown in FIG. 12 (3).

  The above operation is repeated three times. Then, in the middle of the fourth operation, as shown in FIG. 12 (3), the regenerative load factor Rr of the inverter device 3a in the regenerative state reaches the fourth threshold Rsp.

  When the regenerative load factor Rr of the inverter device 3a in the regenerative state reaches time tg1 at which the fourth threshold Rsp is reached, the mask signal G of the inverter device 3a in the regenerative state becomes logic 1. After time tg1, the control signal SW of the inverter device 3a in the regenerative state changes to the L level. After that, the current flowing through the resistor 341 in the regeneration circuit 34 of the inverter device 3a in the regeneration state is stopped. On the other hand, DC voltage Vdc continues to rise, and in inverter devices 3b to 3n in the power running state, DC voltage Vdc reaches second threshold value Vth2.

  Thereafter, the inverter devices 3b to 3n in the powering state change the DC voltage Vdc between the second threshold Vth2 and the third threshold Vth3 and at the same time, the resistances of the regenerative circuits 34 in the inverter devices 3b to 3n in the powering state. The unit 341 continues to consume the regenerative power. While the resistors 341 of the inverter devices 3b to 3n in the power running state consume the regenerative power, the regenerative load factor Rr of the inverter device 3a in the regenerative state continues to decrease as shown in FIG. 12 (3). .

  Thereafter, the regenerative load factor Rr of the inverter device 3a in the regenerative state reaches the fifth threshold Rst. When the regenerative load factor Rr of the inverter device 3a in the regenerative state reaches the fifth threshold Rst, the mask signal G of the inverter device 3a in the regenerative state becomes logic 0. When the mask signal G of the inverter device 3a in the regenerative state becomes logic 0, the inverter device 3a in the regenerative state can consume the regenerative power again.

  The counting unit 3691, the fourth comparing unit 3694, the fifth comparing unit 3695, the state holding unit 3696, and the second switching unit 3697 according to the second embodiment are formed in a programmable gate array by software processing with a microcomputer. Can be realized by a combination of circuits or discrete semiconductor elements.

  The fourth storage unit 3692 and the fifth storage unit 3693 can be realized by a storage unit of a microcomputer, a RAM area or a ROM area in a programmable gate array, or a semiconductor memory.

  In the above, Embodiment 2 demonstrated the case where one inverter apparatus 3 in a regeneration state was one. In the case where there are a plurality of inverter devices 3 in the regenerative state, it is apparent that the operation described in the first embodiment is performed.

  Moreover, in the inverter device 3 in the power running state, as described in the first embodiment, it is obvious that the voltage detection circuit 32 has a variation. The operation in the case where the DC voltage Vdc reaches the second threshold Vth2 can be considered to be similar to the case in which the DC voltage Vdc in the first embodiment reaches the first threshold Vth1. is there.

  Further, in the signal So outputted by the regeneration control signal generation unit 367 of the regeneration control circuit 36 B in the second embodiment, each initialization interval of the on time cumulative time Ton and the off level accumulated time Toff is equal to the moment of the resistor 341. Although it is determined by the relationship between the allowable power and the steady allowable power, it is not a matter that affects the configuration of the present invention, so the description here is omitted. Here, each initialization interval of the accumulated time Ton and the accumulated time Toff means a period of counting of the accumulated time Ton and the accumulated time Toff. In addition, as an initialization operation | movement, the example of initialization for every division | segmentation of a series of operation | movement schedule, or the initialization simply for every 1 second of time intervals is mentioned.

  The motor drive system 5 according to the second embodiment is configured as described above and operates as described above. Therefore, in addition to the effects of the first embodiment, the following effects can be obtained.

  First, when regenerative electric power larger than the regenerative electric power assumed by the inverter device 3 occurs, the regenerative electric power from the regenerative circuit 34 of the inverter device 3 in the regenerative state to the regenerative circuit 34 of the inverter device 3 in the powering state Consumption can be distributed. As a result, it is possible to omit the facility expansion of the power storage device for consuming large regenerative power, and to obtain the effect of reducing the facility introduction cost of the entire motor drive system.

  Moreover, consumption of regenerative electric power can be continuously implemented from the regeneration circuit 34 of the inverter device 3 in the regeneration state to the regeneration circuit 34 of the inverter device 3 in the power running state. As a result, since there is no work interruption or interruption of product production, a manufacturing cost reduction effect can be obtained.

  Further, the transition of consumption of regenerative power from the regenerative circuit 34 of the inverter device 3 in the regenerative state to the regenerative circuit 34 of the inverter device 3 in the powering state is performed without the need for the communication function between the inverter devices 3 Can. Thereby, the communication function between the inverter devices 3 can be omitted. As a result, the rate of operation of the system can be increased through the reduction of the failure point, and the maintenance cost can be reduced.

  Next, a modification of regeneration control signal mask portion 369 in the second embodiment will be described with reference to FIG. FIG. 13 is a block diagram showing a detailed configuration of a regeneration control signal mask portion 369A in which the configuration of the regeneration control signal mask portion 369 shown in FIG. 11 is modified. As shown in FIG. 13, the regeneration control signal mask unit 369A holds the state of the counting unit 3691a, the fourth storage unit 3692, the fifth storage unit 3693, the fourth comparison unit 3694, and the fifth comparison unit 3695. A unit 3696 and a second switching unit 3697 are provided.

  The functions of the fourth storage unit 3692, the fifth storage unit 3693, the fourth comparison unit 3694, the fifth comparison unit 3695, the state holding unit 3696, and the second switching unit 3697 are the same as or equivalent to those shown in FIG. I will omit duplicate explanations.

In the counting unit 3691a, the following points are changed from the configuration of FIG. 11 in FIG.
The input signal of the counting unit 3691a is changed from the signal So output from the regeneration control signal generation unit 367 to the signal Sm output from the second switching unit 3697.
-There is no input of the mask signal G which is a selection signal in the counting part 3691a.

  The counting unit 3691a performs the calculation represented by the following equation (4) to generate the regenerative load factor Rr.

  Rr = Ton / (Ton + Toff) (4)

  Ton in the equation (4) is the cumulative time of the on level masked by the signal So output from the regeneration control signal generator 367 in the second switching unit 3697. Further, Toff in the above equation (4) is the cumulative time of the off level masked by the signal So output from the regeneration control signal generator 367 in the second switching unit 3697.

  A regeneration control signal mask unit 369A, which is a modification of regeneration control signal mask unit 369 according to the second embodiment, is configured as described above, and outputs a signal Sm that is the same as or equivalent to regeneration control signal mask unit 369 that is a basic configuration. Do. Therefore, the regeneration control signal mask unit 369A, which is a modified example, exhibits the same or equivalent effects as the regeneration control signal mask unit 369 which is the basic configuration.

Third Embodiment
Second Embodiment In the second embodiment, the embodiment has been described in which the regenerative power is large and exceeds the steady power allowable value Wmax of the resistor 341 in the inverter device 3 in the regenerative state. However, in the restriction of the resistor 341, there is also a steady-state allowable temperature which is an allowable value of heat generation. Therefore, in the third embodiment, a mode suitable for the case where the regenerative electric power is large and the steady-state allowable temperature of the resistor 341 in the inverter device 3 in the regenerative state is exceeded will be described.

  FIG. 14 is a block diagram showing a detailed configuration of the regeneration control circuit 36C in the third embodiment. In regenerative control circuit 36C, in the configuration of regenerative control circuit 36 of the first embodiment shown in FIG. 5, regenerative control signal mask portion 370 is inserted between regenerative control signal generating portion 367 and regenerative control signal amplifying portion 368. It is done. The other configuration is the same as or equivalent to the configuration of FIG. 5, and the same or equivalent components are denoted by the same reference numerals and redundant description will be omitted.

  FIG. 15 is a block diagram showing a detailed configuration of regeneration control signal mask portion 370 in the third embodiment. As shown in FIG. 15, the regeneration control signal mask unit 370 in the third embodiment has a heat storage estimation unit 3701, a sixth storage unit 3702, a seventh storage unit 3703, a sixth comparison unit 3704, and a seventh comparison. A unit 3705, a second state holding unit 3706, and a third switching unit 3707 are provided.

  The heat storage estimation unit 3701 counts the cumulative time Ton of the on level of the signal So output by the regeneration control signal generation unit 367 and the cumulative time Toff of the off level. Next, the heat storage estimation unit 3701 calculates the estimated temperature Kr of the resistor 341 based on the accumulated time Ton, the accumulated time Toff, and the mask signal G output from the second state holding unit 3706.

  Specifically, the heat storage estimation unit 3701 performs an operation represented by the following equation (5) to estimate the estimated temperature Kr.

  Kr = A · (Ton &! G)-B · {(Ton & G) + Toff} ... (5)

  In the above equation (5), “&” is a binary operator representing a logical product. Also, “! G” is an inverted signal of the mask signal G. The meaning of the inverted signal of the mask signal G is the same as that of the first embodiment.

  “A” in the equation (5) is a heat generation and heat storage characteristic coefficient of the resistor 341 in the inverter device 3. The heat generation and heat storage characteristic coefficient is a constant representing the temperature rise when the resistor 341 consumes power of (Vth1 · Vth1) / R per unit time. “R” is the resistance value of the resistor 341. Further, “B” in the above equation (5) is a heat radiation characteristic coefficient of the resistor 341 in the inverter device 3. The heat radiation characteristic coefficient is a constant representing a falling temperature when the resistor 341 does not flow current for a unit time. In both A and B, the unit time is generally in seconds. A and B can be determined by measurement at the time of design or manufacture of the inverter device 3.

  In the above equation (5), the first term is a term for estimating the temperature rise of the resistor 341 in the inverter device 3. The second term is a term for estimating the temperature drop of the resistor 341 in the inverter device 3.

  The estimated temperature Kr calculated by the heat storage estimation unit 3701 is output to the sixth comparison unit 3704 and the seventh comparison unit 3705.

  The sixth storage unit 3702 stores a sixth threshold Ku. The sixth threshold Ku is output to the sixth comparison unit 3704. The sixth threshold Ku is selected to a value slightly lower than the steady-state allowable temperature Kmax of the resistor 341 or the steady-state allowable temperature Kmax. The steady-state allowable temperature Kmax is a power generation allowable value of the resistor 341.

  Seventh storage unit 3703 stores seventh threshold Kd. The seventh threshold Kd is output to the seventh comparison unit 3705. A value satisfying the following equation (6) can be selected as the seventh threshold value Kd. However, in practice, a value close to the upper limit value of the operating temperature of the inverter device 3 or an ambient temperature immediately before the inverter device 3 consumes regenerative power is often employed.

  0 <Kd <Ku (6)

  The sixth comparison unit 3704 compares the estimated temperature Kr with the sixth threshold Ku. When the estimated temperature Kr is equal to or higher than the sixth threshold Ku, the sixth comparing unit 3704 outputs a signal KP indicating significance to the second state holding unit 3706.

  Here, the case where the signal KP is significant is referred to as "one level". Also, the case where the signal KP is not significant is referred to as "0 level". That is, the state in which the signal KP is “1 level” is the state of Kr ≧ Ku, and the state in which the signal KP is “0 level” is the state of Kr <Ku. Here, the state of Kr = Ku is included in the “1 level”, but the state of Kr = Ku may be included in the “0 level”.

  The seventh comparison unit 3705 compares the estimated temperature Kr with the seventh threshold Kd. When the estimated temperature Kr is equal to or lower than the seventh threshold value Kd, the seventh comparison unit 3705 outputs a signal KS indicating significance to the second state holding unit 3706. When the signal KS is significant, it is called "one level". Also, the case where the signal KS is not significant is called "0 level". That is, the state in which the signal KS is “1 level” is the state of Kr ≦ Kd, and the state in which the signal KS is “0 level” is the state of Kr> Kd. Here, although the state of Kr = Kd is included in the “1 level”, the state of Kr = Kd may be included in the “0 level”.

  The second state holding unit 3706 generates a mask signal G based on the signal KP and the signal KS. The mask signal G is output to the heat storage estimation unit 3701 and the third switching unit 3707. The second state holding unit 3706 sets the mask signal G to logic 1 at the timing when the signal KP changes from “0 level” to “1 level”. Also, the second state holding unit 3706 sets the mask signal G to logic 0 at the timing when the signal KS changes from “0 level” to “1 level”.

  The third switching unit 3707 generates a signal Sm based on the signal So output from the regeneration control signal generation unit 367 and the mask signal G. Signal Sm is output to regeneration control signal amplification unit 368. The third switching unit 3707 fixes the signal Sm to the off level during the period when the mask signal G is logic 1 and the on level and the off level of the signal So as they are during the period when the mask signal G is logic 0. Transmit to That is, the third switching unit 3707 passes the signal So to the signal Sm as it is while the mask signal G is at logic 0 and continues to output the off level while the mask signal G is at logic 1.

  Next, the operation of the regeneration control circuit 36C according to the third embodiment will be described with reference to FIGS. 14 to 16 as appropriate. FIG. 16 is a diagram for explaining the operation of the regeneration control circuit 36C in the third embodiment.

  In the operation description of the third embodiment, one inverter device 3a of the motor drive system 5 is in the regenerative state, the other inverter devices 3b to 3n are in the powering state, and the regenerative power of the inverter device 3a is the inverter. Consider the case where the sum of the power running powers of the devices 3b to 3n is larger.

  The following waveforms are shown in FIG. 16 from the top to the bottom on the same time axis.

(1) DC voltage Vdc
(2) Signal So of inverter device 3a
(3) Estimated temperature Kr of inverter device 3a
(4) Mask signal G of inverter device 3a
(5) Control signal SW of inverter device 3a
(6) Signals So of other inverter devices 3b to 3n
(7) Estimated temperature Kr of other inverter devices 3b to 3n
(8) Mask signal G of other inverter devices 3b to 3n
(9) Control signals SW of other inverter devices 3b to 3n

  FIG. 16A schematically shows a change in DC voltage Vdc when regenerative power is generated in a period from time ts to time te. As shown in FIG. 16 (1), when regenerative power occurs, the DC voltage Vdc rises.

  When the DC voltage Vdc reaches the first threshold value Vth1 of the inverter device 3a in the regenerative state, as shown in FIG. 16 (2), the signal So of the inverter device 3a in the regenerative state changes to the H level. At this time, current flows in the resistor 341 in the regeneration circuit 34 of the inverter device 3a in the regeneration state.

  The estimated temperature Kr calculated by the heat storage estimation unit 3701 of the inverter device 3a in the regenerative state increases as shown in FIG. 16 (3). However, the estimated temperature Kr has not yet reached the sixth threshold Ku. For this reason, as shown in FIG. 16 (4), the mask signal G of the inverter device 3a in the regenerative state remains 0. Therefore, as shown in FIG. 16 (5), the control signal SW of the inverter device 3a in the regenerative state has the same waveform as that of the signal So. Thereby, the regeneration circuit 34 of the inverter device 3a in the regeneration state continues the regeneration process. As shown in FIG. 16 (1), the DC voltage Vdc drops toward the third threshold value Vth3 due to the regeneration processing by the regeneration circuit 34 of the inverter device 3a in the regeneration state.

  When the DC voltage Vdc becomes smaller than the third threshold value Vth3, as shown in FIG. 16 (2), the signal So of the inverter device 3a in the regenerative state changes to L level, and the regenerative circuit of the inverter device 3a in the regenerative state. The current flowing to the resistor 341 in 34 stops. The estimated temperature Kr calculated by the heat storage estimation unit 3701 of the inverter device 3a in the regenerative state decreases as shown in FIG. 16 (3).

  The above operation is repeated three times. Then, in the middle of the fourth operation, as shown in FIG. 16 (3), the estimated temperature Kr of the inverter device 3a in the regenerative state reaches the sixth threshold Ku.

  When the estimated temperature Kr of the inverter device 3a in the regenerative state reaches the time tg2 at which the sixth threshold Ku is reached, as shown in FIG. 16 (4), the mask signal G of the inverter device 3a in the regenerative state becomes logic 1 . After time tg2, as shown in FIG. 16 (5), the control signal SW of the inverter device 3a in the regenerative state changes to L level. After that, the current flowing through the resistor 341 in the regeneration circuit 34 of the inverter device 3a in the regeneration state is stopped. On the other hand, the DC voltage Vdc continues to rise, and the inverter devices 3b to 3n in the power running state reach the second threshold value Vth2.

  Thereafter, the inverter devices 3b to 3n in the powering state change the DC voltage Vdc between the second threshold Vth2 and the third threshold Vth3 and at the same time, the resistances of the regenerative circuits 34 in the inverter devices 3b to 3n in the powering state. The unit 341 continues to consume the regenerative power. As shown in FIG. 16 (3), the estimated temperature Kr of the inverter device 3a in the regenerative state continues to decrease while the resistors 341 of the inverter devices 3b to 3n in the power running state consume the regenerative power.

  Thereafter, the estimated temperature Kr of the inverter device 3a in the regenerative state reaches the seventh threshold Kd. When the estimated temperature Kr of the inverter device 3a in the regenerative state reaches the seventh threshold Kd, as shown in FIG. 16 (4), the mask signal G of the inverter device 3a in the regenerative state becomes logic 0. When the mask signal G of the inverter device 3a in the regenerative state becomes logic 0, the inverter device 3a in the regenerative state can consume the regenerative power again.

  Thereafter, the inverter devices 3b to 3n in the powering state change the DC voltage Vdc between the second threshold Vth2 and the third threshold Vth3 and at the same time, the resistances of the regenerative circuits 34 in the inverter devices 3b to 3n in the powering state. The unit 341 continues to consume the regenerative power. As shown in FIG. 16 (3), the estimated temperature Kr of the inverter device 3a in the regenerative state continues to decrease while the resistors 341 of the inverter devices 3b to 3n in the power running state consume the regenerative power.

  The heat storage estimation unit 3701, the sixth comparison unit 3704, the seventh comparison unit 3705, the second state holding unit 3706, and the third switching unit 3707 according to the third embodiment perform software processing in a microcomputer and a programmable gate array. It can be realized by a combination of circuits or discrete semiconductor elements.

  The sixth storage unit 3702 and the seventh storage unit 3703 can be realized by a storage unit of a microcomputer, a RAM area or a ROM area in a programmable gate array, or a semiconductor memory.

  As mentioned above, Embodiment 3 demonstrated the case where one inverter apparatus 3 in a regeneration state was one. In the case where there are a plurality of inverter devices 3 in the regenerative state, it is apparent that the operation in the case described in the first embodiment is performed.

  Moreover, in the inverter device 3 in the power running state, as described in the first embodiment, it is obvious that the voltage detection circuit 32 has a variation. The operation in the case where the DC voltage Vdc reaches the second threshold Vth2 can be considered to be similar to the case in which the DC voltage Vdc in the first embodiment reaches the first threshold Vth1. is there.

  In addition, in the signal So output by the regeneration control signal generation unit 367 of the regeneration control circuit 36C in the third embodiment, each initialization interval of the on time accumulated time Ton and the off level accumulated time Toff is equal to the moment of the resistor 341 Although it is determined by the relationship between the allowable temperature and the steady-state allowable temperature, it does not affect the configuration of the present invention, and thus the description thereof is omitted. Here, each initialization interval of the cumulative time Ton and the cumulative time Toff means a period of counting of the cumulative time Ton and the cumulative time Toff. In addition, as an initialization operation | movement, the example of initialization for every division | segmentation of a series of operation | movement schedule, or the initialization simply for every 1 second of time intervals is mentioned.

  The motor drive system 5 according to the third embodiment is configured as described above and operates as described above. Therefore, in addition to the effects of the first embodiment, the following effects can be obtained.

  First, when heat generation larger than the heat generation assumed by the inverter device 3 occurs, consumption of regenerative power from the regenerative circuit 34 of the inverter device 3 in the regenerative state to the regenerative circuit 34 of the inverter device 3 in the powering state Can be distributed. As a result, it is possible to omit the enhancement of the heat dissipation device for consuming a large amount of regenerative power, and to obtain the effect of reducing the installation cost of the entire motor drive system.

  Moreover, consumption of regenerative electric power can be continuously implemented from the regeneration circuit 34 of the inverter device 3 in the regeneration state to the regeneration circuit 34 of the inverter device 3 in the power running state. As a result, since there is no work interruption or interruption of product production, a manufacturing cost reduction effect can be obtained.

  The transition of consumption of regenerative power from the regenerative circuit 34 of the inverter device 3 in the regenerative state to the regenerative circuit 34 of the inverter device 3 in the powering state can be implemented without the need for the communication function between the inverter devices 3 it can. Thereby, the communication function between the inverter devices 3 can be omitted. As a result, the rate of operation of the system can be increased through the reduction of the failure point, and the maintenance cost can be reduced.

  Next, a modification of regeneration control signal mask portion 370 in the third embodiment will be described with reference to FIG. FIG. 17 is a block diagram showing a detailed configuration of a regeneration control signal mask portion 370A in which the configuration of the regeneration control signal mask portion 370 shown in FIG. 15 is modified. As shown in FIG. 17, the regeneration control signal mask unit 370A includes a heat storage estimation unit 3701a, a sixth storage unit 3702, a seventh storage unit 3703, a sixth comparison unit 3704, a seventh comparison unit 3705, and A two-state holding unit 3706 and a third switching unit 3707 are provided.

  The functions of the sixth storage unit 3702, the seventh storage unit 3703, the sixth comparison unit 3704, the seventh comparison unit 3705, the second state holding unit 3706, and the third switching unit 3707 are the same as or equivalent to those shown in FIG. Yes, I will omit duplicate explanations.

In the heat storage estimation unit 3701a, the following points are changed from the configuration of FIG. 15 in FIG.
The input signal of the heat storage estimation unit 3701a is changed from the signal So output from the regeneration control signal generation unit 367 to the signal Sm output from the third switching unit 3707.
The heat storage estimation unit 3701a does not have an input of the mask signal G which is a selection signal.

  The heat storage estimation unit 3701a performs an operation represented by the following equation (7) to estimate the estimated temperature Kr.

  Kr = A · Ton-B · Toff (7)

  Ton in the above equation (7) is the cumulative time of the on level masked by the signal So output from the regeneration control signal generator 367 in the third switching unit 3707. Further, Toff in the above equation (7) is the cumulative time of the off level masked by the signal So output by the regeneration control signal generator 367 in the third switching unit 3707.

  Regeneration control signal mask portion 370A, which is a modification of regeneration control signal mask portion 370 in the third embodiment, is configured as described above, and outputs a signal Sm identical or equivalent to that of regeneration control signal mask portion 370 which is a basic configuration. Do. For this reason, the regeneration control signal mask unit 370A, which is a modified example, exhibits the same or equivalent effects as the regeneration control signal mask unit 370 which is the basic configuration.

Fourth Embodiment
In the second embodiment, the technology in which the inverter device 3 in the power running state shares the consumption of the regenerative power when the regenerative power in which the resistor 341 of the inverter device 3 in the regenerative state becomes the steady power allowable value Wmax or more occurs. Explained. Further, in the third embodiment, the technology in which the inverter device 3 in the power running state shares the consumption of the regenerative power when the regenerative electric power in which the resistor 341 of the inverter device 3 in the regenerative state becomes equal to or higher than the steady state allowable temperature occurs. Explained.

  On the other hand, when the resistor 341 of the inverter device 3 in the regenerative state exceeds the steady power allowable value Wmax or more due to the regenerative power, and when the resistor 341 of the inverter device 3 in the regenerative state exceeds the steady allowable temperature There is also a relationship between the ambient temperature of the inverter device 3 and it is an independently occurring event.

  Therefore, in the fourth embodiment, the case where the resistor 341 of the inverter device 3 in the regenerative state becomes equal to or higher than the steady power allowable value Wmax and the case where the resistor 341 of the inverter device 3 in the regenerative state becomes equal to or higher than the steady allowable temperature A motor drive system capable of coping with both events will be described.

  FIG. 18 is a block diagram showing a detailed configuration of a regeneration control circuit 36D in the fourth embodiment. In the regeneration control circuit 36D, the regeneration control signal mask portion 369 in the regeneration control circuit 36B of the second embodiment shown in FIG. 10 is replaced with a regeneration control signal mask portion 369B. The other configuration is the same as or equivalent to the configuration of FIG. 10, and the same or equivalent components are denoted by the same reference numerals and redundant description will be omitted.

  FIG. 19 is a block diagram showing a detailed configuration of a regeneration control signal mask unit 369B in the fourth embodiment. As shown in FIG. 19, regenerative control signal mask unit 369B in the fourth embodiment includes counting unit 3691, fourth storing unit 3692, fifth storing unit 3693, fourth comparing unit 3694, and fifth comparing unit. 3695, a state holding unit 3696, a second switching unit 3697, a heat storage estimation unit 3701, a sixth storage unit 3702, a seventh storage unit 3703, a sixth comparison unit 3704, and a seventh comparison unit 3705; A second state holding unit 3706 and a third switching unit 3707 are provided. In FIG. 19, the same or equivalent parts as those shown in the first to third embodiments are given the same reference numerals.

  The counting unit 3691 calculates the regeneration load rate Rr described in the second embodiment based on the signal So output from the regeneration control signal generation unit 367 and the first mask signal G1 output from the state holding unit 3696. The calculated regenerative load factor Rr is output to the fourth comparison unit 3694 and the fifth comparison unit 3695.

  The fourth storage unit 3692, the fifth storage unit 3693, the fourth comparison unit 3694, and the fifth comparison unit 3695 have the same functions as in the second embodiment, and the operations are also the same.

  The state holding unit 3696 only has the name of the output signal changed to the first mask signal G1, and the function and operation are also the same as those of the second embodiment.

  The second switching unit 3697 performs the same operation as that of the second embodiment based on the signal So, which is the output of the regeneration control signal generation unit 367, and the first mask signal G1. In FIG. 19, the output notation of the second switching unit 3697 is changed to “So1”.

  The heat storage estimation unit 3701 receives the signal So1 output from the second switching unit 3697. The heat storage estimation unit 3701 calculates the estimated temperature Kr described in the third embodiment based on the signal So1 and the second mask signal G2 output from the second state storage unit 3706. The estimated temperature Kr thus calculated is output to the sixth comparison unit 3704 and the seventh comparison unit 3705.

  The sixth storage unit 3702, the seventh storage unit 3703, the sixth comparison unit 3704, and the seventh comparison unit 3705 have the same functions as in the third embodiment, and the operations are also the same.

  In the second state holding unit 3706, only the name of the output signal is changed to the second mask signal G2, and the function and operation are also the same as those in the third embodiment.

  The third switching unit 3707 generates a signal Sm based on the signal So1 output from the second switching unit 3697 and the second mask signal G2. Signal Sm is output to regeneration control signal amplification unit 368. The third switching unit 3707 fixes the signal Sm at the off level while the second mask signal G2 is at logic 1 and the on level and off level of the signal So1 while the second mask signal G2 is at logic 0. Directly to the signal Sm. That is, the third switching unit 3707 keeps the signal So1 passing to the signal Sm as it is while the second mask signal G2 is at logic 0, and keeps outputting the off level during the period when the second mask signal G2 is at logic 1.

  As described above, the regenerative control signal mask unit 369B according to the fourth embodiment is a series connection of the regenerative control signal mask unit 369 according to the second embodiment and the regenerative control signal mask unit 370 according to the third embodiment. It is. The order of connection may be reversed, and it is apparent that the same effect can be obtained.

  Since the motor drive system according to the fourth embodiment is configured as described above and operates as described above, in addition to the effects of the first embodiment, the effects of the second embodiment and the effects of the third embodiment It produces a combined effect.

  The configuration shown in the above embodiment shows an example of the content of the present invention, and can be combined with another known technique, and a configuration without departing from the scope of the present invention It is also possible to omit or change part of.

  DESCRIPTION OF SYMBOLS 1 power supply part, 2 DC bus, 2a high electric potential side conductor, 2b low electric potential side conductor, 3, 3a, 3b-3n inverter apparatus, 4, 4a, 4b-4n motor, 5 motor drive system, 31 electric power conversion circuit, 32 Voltage detection circuit, 33 smoothing capacitor, 34 regeneration circuit, 34a series circuit, 35 state distinction circuit, 36, 36A, 36B, 36C, 36D regeneration control circuit, 311 switching circuit, 311a, 342 semiconductor switch element, 311c connection point, 311d Diode, 312 switching circuit control circuit, 313 current detection circuit, 341 resistor, 361 first storage unit, 362 second storage unit, 363 third storage unit, 364, 364a switching unit, 365, 365a first comparison unit, 366 Second comparison unit, 365b Third comparison unit, 367 Regeneration control signal generation unit , 368 regenerative control signal amplification unit, 369, 369A, 369B, 370, 370A regenerative control signal mask unit, 3691, 3691a counting unit, 3692 fourth storage unit, 3693 fifth storage unit, 3694 fourth comparison unit, 3695 fifth Comparison unit, 3696 state holding unit, 3697 second switching unit, 3701, 3701a heat storage estimation unit, 3702 sixth storage unit, 3703 seventh storage unit, 3704 sixth comparison unit, 3705 seventh comparison unit, 3706 second state holding Part, 3707 third switching part.

Claims (12)

A plurality of inverter devices are provided to drive a motor by converting direct current power supplied via a direct current bus having a high potential side conductor and a low potential side conductor into alternating current power, and the plurality of inverter devices are parallel to each other in the direct current bus A motor drive system connected to the
Each of the inverter devices
A power conversion circuit that converts the DC power into the AC power;
A voltage detection circuit that detects a DC voltage applied to the power conversion circuit;
A smoothing capacitor connected in parallel to the power conversion circuit;
A regenerating circuit having a resistor and a semiconductor switch element connected in series, wherein the resistor and the semiconductor switch element are connected between the high potential side conductor and the low potential side conductor;
A state determination circuit that determines whether the power conversion circuit is in a regeneration state;
A regeneration control circuit that controls the semiconductor switch element of the regeneration circuit to a conductive state or a cut-off state based on the determination result by the state determination circuit and the comparison result of the DC voltage and a determination threshold value;
Equipped with
The regeneration control circuit is
A first threshold, a second threshold having a value larger than the first threshold, and a third threshold having a value smaller than the first threshold are held,
A switching unit that outputs the first threshold when the determination result of the state determination circuit is in the regenerative state, and outputs the second threshold when the determination result of the state determination circuit is not in the regenerative state;
A first comparison unit that outputs a signal indicating significance when the output of the voltage detection circuit is larger than the output value of the switching unit;
A second comparison unit that outputs a signal indicating significance when the output of the voltage detection circuit is smaller than the third threshold;
A regenerative control signal is provided to turn on the semiconductor switch element at a timing when the output of the first comparison section becomes significant and to turn off the semiconductor switch element at a timing when the output of the second comparison section becomes significant. A regenerative control signal generation unit to generate;
A motor drive system comprising: A plurality of inverter devices are provided to drive a motor by converting direct current power supplied via a direct current bus having a high potential side conductor and a low potential side conductor into alternating current power, and the plurality of inverter devices are parallel to each other in the direct current bus A motor drive system connected to the
Each of the inverter devices
A power conversion circuit that converts the DC power into the AC power;
A voltage detection circuit that detects a DC voltage applied to the power conversion circuit;
A smoothing capacitor connected in parallel to the power conversion circuit;
A regenerating circuit having a resistor and a semiconductor switch element connected in series, wherein the resistor and the semiconductor switch element are connected between the high potential side conductor and the low potential side conductor;
A state determination circuit that determines whether the power conversion circuit is in a regeneration state;
A regeneration control circuit that controls the semiconductor switch element of the regeneration circuit to a conductive state or a cut-off state based on the determination result by the state determination circuit and the comparison result of the DC voltage and a determination threshold value;
Equipped with
The regeneration control circuit is
A first threshold, a second threshold having a value larger than the first threshold, and a third threshold having a value smaller than the first threshold are held,
A first comparison unit that outputs a first signal indicating that the output of the voltage detection circuit is greater than the first threshold;
A second comparison unit that outputs a second signal indicating that the output of the voltage detection circuit is smaller than the third threshold;
A third comparison unit that outputs a third signal indicating that the output of the voltage detection circuit is greater than the second threshold;
The first signal is output based on the first signal and the third signal when the determination result of the state determination circuit is in the regenerative state, and the determination result of the state determination circuit is not in the regenerative state. A switching unit for outputting the third signal;
The semiconductor switching device is brought into conduction at a timing when the output of the switching unit becomes significant, and a regeneration control signal is generated for bringing the semiconductor switching device into a disconnection state at a timing when the output of the second comparing unit becomes significant. A regenerative control signal generator,
A motor drive system comprising:   The regenerative control signal amplification unit according to claim 1 or 2, further comprising: a regenerative control signal amplification unit that amplifies the regenerative control signal to a voltage amplitude or current amount that can drive the semiconductor switch element and outputs the amplified signal to the semiconductor switch element. Motor drive system. The regeneration control circuit includes a regeneration control signal mask unit between the regeneration control signal generation unit and the regeneration control signal amplification unit.
The regeneration control signal mask unit amplifies the regeneration control signal in which the semiconductor switch element is prevented from being brought into the conduction state and continues the cutoff state based on the output of the regeneration control signal generation unit. The motor drive system according to claim 3, wherein the motor drive system outputs to a unit.   The regeneration control signal mask unit calculates the time ratio when the semiconductor switch element is in the conductive state based on the output of the regeneration control signal generation unit, and the calculated time ratio becomes larger than the fourth threshold. 5. The motor drive system according to claim 4, wherein the semiconductor switch element is maintained in the disconnection state until the timing when the time ratio becomes smaller than the fifth threshold smaller than the fourth threshold. The regeneration control signal mask unit
A counting unit that outputs the time ratio as a regenerative load factor;
A fourth comparison unit that outputs a signal indicating that the regenerative load factor is greater than the fourth threshold;
A fifth comparison unit that outputs a signal indicating that the regenerative load factor is smaller than the fifth threshold;
A state holding unit that outputs a signal for maintaining the semiconductor switch element in the cut-off state between the timing when the output signal of the fourth comparing unit becomes significant and the timing when the output signal of the fifth comparing unit becomes significant ,
During a period in which the output of the state holding unit is significant, the output of the regeneration control signal generating unit is forcibly output so that the semiconductor switch element is in the cutoff state, and in a period in which the output of the state holding unit is not significant, A second switching unit that outputs the output of the regeneration control signal generation unit as it is;
The motor drive system according to claim 5, comprising:   The regeneration control signal mask unit estimates the temperature rise of the resistor based on the time during which the semiconductor switch device is in the conductive state and the heat storage characteristic of the resistor, and the semiconductor switch device is cut off. From the timing at which the estimated temperature of the resistor is calculated by estimating the temperature drop of the resistor based on the time in the state and the heat radiation characteristic of the resistor, and the calculated estimated temperature becomes larger than the sixth threshold, The motor drive system according to claim 4, wherein the semiconductor switch element is maintained in the cutoff state until the estimated temperature becomes smaller than a seventh threshold smaller than the sixth threshold. The regeneration control signal mask unit
A sixth comparison unit that outputs a signal indicating that the estimated temperature is greater than the sixth threshold;
A seventh comparison unit that outputs a signal indicating that the estimated temperature is smaller than the seventh threshold;
A state holding unit that outputs a signal for keeping the semiconductor switch element in the shutoff state from the timing when the output of the sixth comparing unit becomes significant to the timing when the output of the seventh comparing unit becomes significant;
During a period in which the output of the state holding unit is significant, the output of the regeneration control signal generating unit is forcibly output so that the semiconductor switch element is in the cutoff state, and in a period in which the output of the state holding unit is not significant, A third switching unit that outputs the output of the regeneration control signal generation unit as it is;
The motor drive system according to claim 7, comprising: The regeneration control signal mask unit calculates the time ratio when the semiconductor switch element is in the conductive state based on the output of the regeneration control signal generation unit, and the calculated time ratio becomes larger than the fourth threshold. The semiconductor switch element is maintained in the cut-off state until the timing when the time ratio becomes smaller than the fifth threshold smaller than the fourth threshold,
The temperature rise of the resistor is estimated based on the time during which the semiconductor switching device is in a conducting state and the heat storage characteristic of the resistor, and the time during which the semiconductor switching device is in a blocking state, and the resistance The estimated temperature of the resistor is calculated by estimating the temperature drop based on the heat release characteristics of the heater, and the estimated temperature is the sixth threshold from the timing when the calculated estimated temperature becomes larger than the sixth threshold. The motor drive system according to claim 4, wherein the semiconductor switch element is maintained in the disconnection state until the timing when it becomes smaller than a seventh threshold value, which is smaller than the seventh threshold value. A motor drive system is connected to a DC bus having a high potential side conductor and a low potential side conductor, and one or more other inverter devices connected to the DC bus, the DC being supplied via the DC bus An inverter device that converts electric power into AC power to drive a motor,
The inverter device
A power conversion circuit that converts the DC power into the AC power;
A voltage detection circuit that detects a DC voltage applied to the power conversion circuit;
A smoothing capacitor connected in parallel to the power conversion circuit;
A regenerating circuit having a resistor and a semiconductor switch element connected in series, wherein the resistor and the semiconductor switch element are connected between the high potential side conductor and the low potential side conductor;
A state determination circuit that determines whether the power conversion circuit is in a regeneration state;
A regeneration control circuit that controls the semiconductor switch element of the regeneration circuit to a conductive state or a cut-off state based on the determination result by the state determination circuit and the comparison result of the DC voltage and a determination threshold value;
Equipped with
The regeneration control circuit is
A first threshold, a second threshold having a value larger than the first threshold, and a third threshold having a value smaller than the first threshold are held,
A switching unit that outputs the first threshold when the determination result of the state determination circuit is in the regenerative state, and outputs the second threshold when the determination result of the state determination circuit is not in the regenerative state;
A first comparison unit that outputs a signal indicating significance when the output of the voltage detection circuit is larger than the output value of the switching unit;
A second comparison unit that outputs a signal indicating significance when the output of the voltage detection circuit is smaller than the third threshold;
A regenerative control signal is provided to turn on the semiconductor switch element at a timing when the output of the first comparison section becomes significant and to turn off the semiconductor switch element at a timing when the output of the second comparison section becomes significant. A regenerative control signal generation unit to generate;
An inverter device comprising: A motor drive system is connected to a DC bus having a high potential side conductor and a low potential side conductor, and one or more other inverter devices connected to the DC bus, the DC being supplied via the DC bus An inverter device that converts electric power into AC power to drive a motor,
The inverter device
A power conversion circuit that converts the DC power into the AC power;
A voltage detection circuit that detects a DC voltage applied to the power conversion circuit;
A smoothing capacitor connected in parallel to the power conversion circuit;
A regenerating circuit having a resistor and a semiconductor switch element connected in series, wherein the resistor and the semiconductor switch element are connected between the high potential side conductor and the low potential side conductor;
A state determination circuit that determines whether the power conversion circuit is in a regeneration state;
A regeneration control circuit that controls the semiconductor switch element of the regeneration circuit to a conductive state or a cut-off state based on the determination result by the state determination circuit and the comparison result of the DC voltage and a determination threshold value;
Equipped with
The regeneration control circuit is
A first threshold, a second threshold having a value larger than the first threshold, and a third threshold having a value smaller than the first threshold are held,
A first comparison unit that outputs a first signal indicating that the output of the voltage detection circuit is greater than the first threshold;
A second comparison unit that outputs a second signal indicating that the output of the voltage detection circuit is smaller than the third threshold;
A third comparison unit that outputs a third signal indicating that the output of the voltage detection circuit is greater than the second threshold;
The first signal is output based on the first signal and the third signal when the determination result of the state determination circuit is in the regenerative state, and the determination result of the state determination circuit is not in the regenerative state. A switching unit for outputting the third signal;
The semiconductor switching device is brought into conduction at a timing when the output of the switching unit becomes significant, and a regeneration control signal is generated for bringing the semiconductor switching device into a disconnection state at a timing when the output of the second comparing unit becomes significant. A regenerative control signal generator,
An inverter device comprising: A plurality of inverter devices are provided to drive a motor by converting direct current power supplied via a direct current bus having a high potential side conductor and a low potential side conductor into alternating current power, and the plurality of inverter devices are parallel to each other in the direct current bus A motor drive system connected to the
Each of the inverter devices
A power conversion circuit that converts the DC power into the AC power;
A voltage detection circuit that detects a DC voltage applied to the power conversion circuit;
A smoothing capacitor connected in parallel to the power conversion circuit;
A regenerating circuit having a resistor and a semiconductor switch element connected in series, wherein the resistor and the semiconductor switch element are connected between the high potential side conductor and the low potential side conductor;
A state determination circuit that determines whether the power conversion circuit is in a regeneration state;
A first threshold value and a second threshold value larger than the first threshold value are held, and based on the determination result of the state determination circuit, the first threshold value is used to determine whether to turn on the semiconductor switch element. A regeneration control circuit that switches between the second threshold and the second threshold, and controls the semiconductor switch element to a conductive state or a cut-off state based on a comparison result of the switched determination threshold and the DC voltage;
Equipped with
In the regeneration control circuit of the plurality of inverter devices,
The regeneration control circuit of the inverter device that has determined that the determination result of the state determination circuit is in the regenerative state uses the first threshold as a determination threshold,
The regeneration control circuit of the inverter device determined that the determination result of the state determination circuit is not a regeneration state uses the second threshold as a determination threshold ,
The motor drive system characterized by the inverter apparatus which uses said 1st threshold value as a judgment threshold value, and another inverter apparatus which uses said 2nd threshold value as a judgment threshold value exist in the same time .

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