Inverter control system and inverter control method

Abstract

To continue operation of an elevator even when a part of inverters which are connected in parallel fails.SOLUTION: An inverter control system, which supplies a power source to a motor for driving an elevator by N pieces (N is integer of 2 or greater) of inverters which are connected in parallel and controls each of the inverters which are connected in parallel, includes a trouble signal reception part 192 for receiving an abnormal signal of the inverters in a group unit in which N pieces of the inverters that are connected in parallel are divided into a plurality of groups, and a gate command part 191 for operating the inverter of the group other than the group in which the trouble signal reception part receives the abnormal signal.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an inverter control system and an inverter control method. [Background technology]

[0002] Elevators and other elevators use AC motors as their power source. To control the operating state of AC motors, an inverter is used to convert the voltage and frequency of the power supply. For example, in the case of elevators installed in buildings, the three-phase AC power supplied by the power company is converted in voltage and frequency by an inverter before being supplied to the AC motor that makes up the hoist. When converting the voltage and frequency of a three-phase AC power supply using an inverter, specifically, the three-phase AC power supply is converted into DC power supply using a converter, and the converted DC power supply is then converted into AC power supply of the desired voltage and frequency using an inverter. Here, the converter and the inverter can have the same basic configuration, in which case the only difference is that they operate in the opposite direction. In the following explanation, when referring to an inverter, this also includes the converter, unless a distinction is made.

[0003] When using inverters to control the power supply of elevators and other lifts, multiple inverters are connected in parallel depending on the required power capacity, and processing is performed simultaneously by these multiple inverters. That is, inverters are made up of semiconductor switches such as IGBTs (Insulated Gate Bipolar Transistors), and since there are limits to the current and voltage that can pass through a single semiconductor switch, the required power supply capacity is ensured by connecting multiple inverters in parallel. For example, to configure an inverter with an output of 200kW, four inverters, each with an output of 50kW, are connected in parallel to ensure 200kW.

[0004] Patent Document 1 describes a technology for stopping the operation of an inverter device that has been detected as having an abnormality when an abnormality is detected in any of the inverter devices in a system configured with multiple inverter devices. In the technology described in Patent Document 1, abnormalities in the inverter devices are checked for each of the U phase, V phase, and W phase, and abnormalities are detected for each phase, such as a U phase abnormal signal. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-29393 Summary of the Invention [Problem to be solved by the invention]

[0006] As described in Patent Document 1, when an inverter device is configured to detect an abnormality for each of the U, V, and W phases, it is difficult to identify the inverter unit that has failed in an inverter device configured with multiple units. For example, when an abnormality is detected in the U phase, it is difficult to identify which of the multiple units is the abnormality in the U phase, and it cannot be said that the abnormality detection is being performed appropriately.

[0007] For this reason, an inverter device that detects an abnormality cannot be used until the faulty semiconductor switch, etc. is replaced. For example, if an abnormality occurs in an inverter device that drives an elevator, the elevator will be unable to be used until the failure in the inverter device is repaired.

[0008] An object of the present invention is to provide an inverter control system and an inverter control method that enable the elevator to continue operating even if some of the parallel-connected inverters fail. [Means for solving the problem]

[0009] In order to solve the above problems, for example, the configurations described in the claims are adopted. The present application includes a plurality of means for solving the above problems, and examples thereof include: Parallel inverters are connected in parallel, and multiple inverters are grouped into individual groups. The inverter supplies power to the motor that drives the elevator. hand, Each Parallel groups In an inverter control system that controls an inverter , parallel Inverter abnormal signal , individually for each group a trouble signal receiving unit for receiving the trouble signal; When an abnormal signal is received from any group, the parallel inverters of the group that received the abnormal signal are stopped, and the parallel inverters of the group that did not receive the abnormal signal are stopped. a gate command unit that operates the inverter, Number of groups to operate parallel inverters In response to the above, the elevator is restricted from boarding. [Effects of the Invention]

[0010] According to the present invention, inverter abnormalities are detected on a group basis, so inverters for which no abnormality has been detected can be operated, and even if an abnormality occurs in some of the inverters, the elevator can continue to operate. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing a schematic configuration of an inverter device circuit and an elevator controlled by an inverter control system according to an embodiment of the present invention; [Figure 2] 2 is a plan view showing an example of the arrangement of the inverter device shown in FIG. 1. FIG. [Figure 3] 1 is a perspective view showing the shape of one unit of an inverter device controlled by an inverter control system according to an embodiment of the present invention. [Figure 4] 1 is a block diagram showing an example of the configuration of an inverter control system according to an embodiment of the present invention; [Figure 5] 3 is a flowchart illustrating an example of a control process of an inverter control system according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] An inverter control system according to an embodiment of the present invention (hereinafter referred to as "this example") will be described below with reference to the accompanying drawings. The inverter control system of this example is a system for an inverter device that supplies power to a hoisting machine of an elevator, which is a lifting machine.

[0013] [Inverter device configuration] Fig. 1 shows the circuit configuration of the inverter device 100. Fig. 1 also shows a schematic configuration of an elevator to which power is supplied by the inverter device 100. The inverter device 100 includes a first parallel inverter 110, a second parallel inverter 120, . . . , an Nth parallel inverter 190 (N is an integer of 2 or more).

[0014] Two inverter units are connected in series in each of the parallel inverters 110 to 190. For example, the first parallel inverter 110 has two inverter units 111 and 112 connected in parallel. The inverter unit 111 operates as a converter that converts the three-phase AC power supply 11 into DC, and has six semiconductor switches in total: 111-U1, 111-U2, 111-V1, 111-V2, 111-W1, and 111-W2, two for each of the U, V, and W phases. Furthermore, the inverter unit 111 is connected to a capacitor 111-C that smoothes the power supply after conversion to DC. A power supply filter unit 12 is connected between the three-phase AC power supply 11 and the inverter unit 111 .

[0015] Inverter unit 112 converts the DC obtained by inverter unit 111 into a three-phase AC power supply, and has six semiconductor switches in total: 112-U1, 112-U2, 112-V1, 112-V2, 112-W1, and 112-W2, two for each of the U, V, and W phases. A capacitor 112-C is also connected to the DC side of inverter unit 112.

[0016] Similarly, the second parallel inverter 120 to the Nth parallel inverter 190 each include two inverter units 121, 122 to 191, 192. For example, the inverter unit 121 of the second parallel inverter 120 includes six semiconductor switches 121-U1, 121-U2, 121-V1, 121-V2, 121-W1, and 121-W2 and converts three-phase AC power into DC power. Also, the inverter unit 122 of the second parallel inverter 120 includes six semiconductor switches 122-U1, 122-U2, 122-V1, 122-V2, 122-W1, and 122-W2 and converts DC power into three-phase AC power.

[0017] Furthermore, inverter unit 191 of Nth parallel inverter 190 has six semiconductor switches 191-U1, 191-U2, 191-V1, 191-V2, 191-W1, and 191-W2 and operates to convert three-phase AC power into DC power. In addition, inverter unit 192 has six semiconductor switches 192-U1, 192-U2, 192-V1, 192-V2, 192-W1, and 192-W2 and operates to convert DC power into three-phase AC power.

[0018] The second parallel inverter 120 to the N-th parallel inverter 190 each have two inverter units 121, 122 to 191, 192, respectively, connected to capacitors 121-C, 122-C to 191-C, 192-C.

[0019] The semiconductor switches (121-U1, etc.) arranged in each of the inverter units 111, 112 to 191, 192 are made up of semiconductor elements such as IGBTs, and are on / off controlled by the inverter control unit 200 (FIG. 4), which will be described later. In this case, the voltage and frequency for driving the elevator are set by on / off control of the inverter units 112 to 192, which obtain the three-phase AC power supply for each of the parallel inverters 110 to 190.

[0020] The three-phase AC power obtained by the inverter units 112 to 192 of the parallel inverters 110 to 190 is supplied via a reactor 13 to a motor (for example, a three-phase synchronous motor) 14 serving as a hoisting machine for the elevator.

[0021] To briefly explain the elevator configuration, a main rope 16 is wound around a sheave 15 that rotates in conjunction with the rotation of a motor 14. A car 17 is connected to one end of the main rope 16, and a counterweight 19 is connected to the other end, and the car 17 rises and falls as the motor 14 rotates. A load sensor 18 is installed on the car 17 as a load detection unit that detects the load amount of the car 17. The inverter device 100 is installed in, for example, an elevator machine room.

[0022] [Example of inverter device placement] FIG. 2 shows an example of the arrangement of the inverter device 100 of this embodiment. The inverter device 100 in the example of FIG. 2 has a four-parallel configuration of a first parallel inverter 110 to a fourth parallel inverter 140. Each of the parallel inverters 110 to 140 includes two inverter units, so that there are eight inverter units 111 to 141 and 112 to 142 in total.

[0023] Here, as shown in Fig. 2, the inverter device 100 of this example has eight inverter units 111 to 141 and 112 to 142 stacked vertically on the control panel 109. That is, in the example of Fig. 2, the inverter units are arranged in the following order from top to bottom: 111, 121, 131, 141, 112, 122, 132, 142. However, the arrangement of the units shown in Fig. 2 is just an example, and other arrangement orders may also be used.

[0024] Each of the inverter units 111, 112, 121, 122, 131, 132, 141, and 142 includes six semiconductor switches (not shown in FIG. 2), and each unit is equipped with three cooling fans. For example, cooling fans 111-F1, 111-F2, and 111-F3 are attached to the inverter unit 111. Similarly, cooling fans indicated by adding "F1, F2, and F3" to the end of the reference numerals of the inverter units 121 to 141 and 112 to 142 are attached to the inverter units. Handles 101 are attached to the left and right ends of each of the inverter units 111 to 142.

[0025] The four inverter units 111, 121, 131, and 141 operating as converters are connected in parallel to the three terminals 102U, 102V, and 102W of the terminal section 102. The three terminals 102U, 102V, and 102W of the terminal section 102 are connected to the three-phase AC power supply 11 shown in FIG.

[0026] Furthermore, the four inverter units 112, 122, 132, and 142 that operate as inverters are connected in parallel to three terminals 103U, 103V, and 103W of the terminal section 103. The three terminals 103U, 103V, and 103W of the terminal section 103 are connected to the motor 14 side shown in FIG. The parallel inverters 110 to 140 are set to have the same maximum output current.

[0027] [Inverter unit configuration] FIG. 3 is a perspective view showing the configuration of one inverter unit 111. As shown in FIG. The other inverter units 112 to 142 have the same configuration as the inverter unit 111. The inverter unit 111 has three cooling fans 111-F1, 111-F2, and 111-F3 attached to the front side of a frame 107, which also serves as a heat sink. The inverter unit 111 also has six semiconductor switches 111-U1, 111-U2, 111-V1, 111-V2, 111-W1, and 111-W2. In this example, the inverter unit is configured using a 2-in-1 type IGBT module, but 1-in-1 or 6-in-1 types may also be used. The inverter unit 111 also includes a capacitor 111-C and other components. Handles 101 are attached to the left and right ends of the front side of the frame 107.

[0028] Three-phase AC side terminals 104-U, 104-V, and 104-W are arranged on the front side of the upper part of frame 107, and DC side terminals 105-P and 105-N are arranged on the rear side of the upper part of frame 107. In the case of inverter unit 111 operating as a converter, terminals 104-U, 104-V, and 104-W on the three-phase AC side are connected to three-phase AC power supply 11 (FIG. 1). In the case of inverter unit 121 operating as an inverter, terminals 104-U, 104-V, and 104-W on the three-phase AC side are connected to the motor 14 side. The DC side terminals 105-P and 105-N are connected to DC side terminals (not shown) of the inverter units 112 of the same parallel inverter 110.

[0029] [Control configuration of inverter device] Fig. 4 shows the configuration of the inverter device 100 and inverter control unit 200 used in the inverter control system of this example. The inverter device 100 in the example of Fig. 4 is configured to include six parallel inverters 110 to 160. The six parallel inverters 110 to 160 are divided into three groups.

[0030] That is, the first parallel inverter 110 and the second parallel inverter 120 are referred to as a first group inverter 100a, the third parallel inverter 130 and the fourth parallel inverter 140 are referred to as a second group inverter 100b, and the fifth parallel inverter 150 and the sixth parallel inverter 160 are referred to as a second group inverter 100c.

[0031] The semiconductor switches arranged in each of these parallel inverters 110 to 160 are turned on and off by commands from a gate command unit 191 of an inverter control device 190 . In this case, the parallel inverters 110 to 160 are configured to receive gate commands via individual switches 119 to 169, respectively, so that the operation of each of the parallel inverters 110 to 160 can be controlled to stop.

[0032] The inverter control system of this example also includes a trouble signal receiving unit 192 and a trouble handling unit 193. The trouble signal receiving unit 192 performs trouble signal receiving processing to receive abnormality signals from the inverters 110 to 160. The trouble signal receiving unit 192 receives an abnormality signal for each group individually. That is, the trouble signal receiving unit 192 individually receives an abnormality signal when an abnormality occurs in the first group inverter 100a, an abnormality signal when an abnormality occurs in the second group inverter 100b, and an abnormality signal when an abnormality occurs in the third group inverter 100c.

[0033] The abnormality signals received by the trouble signal receiving unit 192 include abnormality signals indicating that the semiconductor switches of each parallel inverter 110 to 160 are not operating, abnormality signals indicating abnormalities in the current or voltage of each parallel inverter 110 to 160, and abnormality signals indicating abnormalities in the temperature of each parallel inverter 110 to 160.

[0034] The troubleshooter 193 determines which group of parallel inverters 110 to 160 has an abnormality, and supplies the gate commander 191 with information on the group in which the abnormality has occurred. The gate command unit 191, which receives information about the group in which an abnormality has occurred from the trouble-shooting unit 193, performs control processing to turn off the switches of the lines controlling the parallel inverters of the corresponding group and to operate only the parallel inverters of the remaining groups. For example, when an abnormality signal is received from the first group inverter, the gate command unit 191 turns off the switches 119 and 129 and operates only the second group parallel inverters 130 and 140 and the third group parallel inverters 150 and 160.

[0035] The troubleshooter 193 also determines the number of parallel inverters that can operate normally, other than the group in which the abnormality occurred. Then, the troubleshooter 193 determines the maximum current that can be supplied to the motor 14 (FIG. 1) from that determination, and instructs an elevator control unit (not shown) to limit the elevator load capacity and speed based on the determined maximum current.

[0036] In FIG. 4, the trouble signal receiving unit 192 and the trouble handling unit 193 are provided outside the inverter control device 190, but the trouble signal receiving unit 192 and the trouble handling unit 193 may be provided inside the inverter control device 190.

[0037] [Control processing by inverter control device] FIG. 5 is a flowchart showing an example of processing when the trouble signal receiving unit 192 receives an abnormality signal. First, the trouble signal receiving unit 192 determines whether or not an abnormality signal has been received (step S11). If an abnormality signal has not been received in step S11 (No in step S11), the gate command unit 191 activates the parallel inverters 110 to 160 in all groups.

[0038] Then, if the trouble signal receiving unit 192 receives an abnormality signal in step S11 (Yes in step S11), the trouble handling unit 193 determines whether or not the abnormality signal is from the inverter 100a of the first group (step S12). If it is determined in step S12 that the signal is not an abnormality signal of the inverter 100a of the first group (No in step S12), the troubleshooter 193 determines whether the signal is an abnormality signal of the inverter 100b of the second group (step S13).

[0039] If the abnormal signal detected in step S13 is not an abnormal signal from the inverter 100b of the second group (No in step S13), the gate command unit 191 determines that the abnormal signal detected in step S11 is an abnormal signal from the inverter 100c of the third group. Then, the gate command unit 191 turns off the switches 159 and 169 to stop the inverter 100c of the third group (parallel inverters 150 and 160) (step S14).

[0040] Then, in the elevator control device (not shown), in response to an instruction from the trouble handling unit 193, the elevator continues to operate using the power supplied by the inverters 100a and 100b of the two groups, excluding the stopped inverter 100c of the third group (step S15). At this time, since the current supplied to the motor 14 is limited, the elevator control unit performs a boarding restriction process that limits the loading rate of the car 17 from the normal 100% and a process that limits the travel speed.

[0041] Furthermore, if it is determined in step S12 that the signal is an abnormality signal from the inverter 100a of the first group (Yes in step S12), the troubleshooter 193 further determines whether or not there is an abnormality signal from the inverter 100b of the second group (step S16). If the inverter 100b of the second group is not outputting an abnormality signal in step S16 (No in step S16), the trouble-shooting unit 193 also determines whether the inverter 100c of the third group is outputting an abnormality signal (step S17).

[0042] If the inverter 100c of the third group does not output an abnormality signal in step S17 (No in step S17), the troubleshooter 193 determines that only the inverter 100a of the first group is abnormal. In this case, the gate commander 191 stops the inverter 100a of the first group and stops the power supply by the inverter 100a of the first group (step S18). That is, in step S18, power is supplied to the motor 14 by the second and third groups of inverters 100b, 100c.

[0043] Then, the process proceeds to step S15, where the elevator control device continues the operation of the elevator after restricting the number of passengers or the speed using the power supplied by the inverters 100b, 100c of the second and third groups.

[0044] If the inverter 100c of the third group is also outputting an abnormality signal in step S17 (Yes in step S17), the troubleshooter 193 determines that the inverters 100a of the first group and the inverters 100c of the third group are abnormal. In this case, the gate commander 191 stops the inverters 100a of the first group and the inverters 100c of the third group, and stops the power supply from the inverters 100a of the first group and the inverters 100c of the third group (step S19). Then, the process proceeds to step S15, and the elevator control device continues the operation of the elevator after restricting the number of passengers or the speed using the power supplied only from the inverter 100b of the second group.

[0045] Furthermore, if the inverter 100b of the second group is outputting an abnormality signal in step S16 (Yes in step S16), it is also determined whether the inverter 100c of the third group is outputting an abnormality signal (step S20).

[0046] In step S20, if the inverter 100c of the third group is outputting an abnormality signal (Yes in step S20), since the inverters 100a to 100c of all groups are outputting abnormality signals, the gate command unit 191 stops the power supply from the inverters 100a to 100c of all groups and stops the elevator (step S21).

[0047] Furthermore, if the inverter 100c of the third group does not output an abnormality signal in step S20 (No in step S20), the troubleshooter 193 determines that the inverter 100a of the first group and the inverter 100b of the second group are abnormal. In this case, the gate commander 191 stops the inverter 100a of the first group and the inverter 100b of the second group (step S22).

[0048] Then, the process proceeds to step S15, where the elevator control device continues the operation of the elevator after restricting the number of passengers or the speed using the power supplied only by the inverter 100c of the third group.

[0049] Also, if the signal is an abnormality signal from the inverter 100b of the second group in step S13 (Yes in step S13), the trouble-shooting unit 193 further determines whether the inverter 100c of the third group is also outputting an abnormality signal (step S23).

[0050] In step S23, if the inverter 100c of the third group is outputting an abnormality signal (Yes in step S23), the troubleshooter 193 determines that the inverters 100b of the second group and the inverters 100c of the third group are abnormal. In this case, the gate commander 191 stops the inverters 100b of the second group and the inverters 100c of the third group (step S24). Then, the process proceeds to step S15, and the elevator control device continues the operation of the elevator after restricting the number of passengers or the speed using the power supplied only from the inverter 100a of the first group.

[0051] If the inverter 100c of the third group does not output an abnormality signal in step S23 (No in step S23), the troubleshooter 193 determines that only the inverter 100b of the second group is abnormal. In this case, the gate commander 191 stops the inverter 100b of the second group (step S25). Then, the process proceeds to step S15, where the elevator control device continues to operate the elevator after imposing a passenger limit or speed limit using the power supplied by the first group inverter 100a and the third group inverter 100c.

[0052] [Effects of control using an inverter control device] 5, even if a failure occurs in one group of the inverter devices 100, the inverters in the remaining groups continue to supply power to the motor 14. Therefore, even if a failure occurs in one of the inverters, the elevator can continue to operate. However, when some inverters fail, the maximum current of the power source supplied to the motor 14 is limited depending on the number of remaining normal groups, so that the number of passengers and the speed of the car 17 are limited, but the elevator service can continue.

[0053] Furthermore, as shown in Figure 4, by configuring a group that detects abnormal signals using multiple parallel inverters, the number of sensors that detect abnormal signals can be made smaller than the number of parallel inverters, making it possible to detect abnormal signals with a simple configuration. In addition, when an inverter in one of the groups fails, the number of passengers in the car 17 and the speed are limited, so that the inverters in the operating groups are not overloaded, and the lifespan of the inverters is not shortened by continued overload operation.

[0054] [Variations] The embodiment examples described so far have been described in detail to clearly explain the present invention, and are not necessarily limited to those having all of the configurations described. For example, the flowchart in Figure 5 describes the process when six parallel inverters 110 to 160 are provided, but the present invention can be applied to a process for selecting an inverter to operate using a similar process when N parallel inverters (N is an integer of 2 or more) are provided. Furthermore, the arrangement of the inverter units 111 to 142 shown in FIG. 2 is also an example, and other configurations are also possible.

[0055] Furthermore, although the above-described embodiment is applied to the control of an inverter device that supplies power to an elevator motor, the present invention may also be applied to the motor of a lift other than an elevator, for example, to the control of an inverter device that supplies power to a motor of an elevator such as an escalator.

[0056] In addition, in the configuration diagram of the control device shown in Figure 4, only the control lines and information lines that are considered necessary for explanation are shown, and not all control lines and information lines in the product are necessarily shown. In reality, it can be assumed that almost all components are interconnected. [Explanation of symbols]

[0057] 11... Three-phase AC power supply, 12... Power supply filter section, 13... Reactor, 14... Motor, 15... Sheave, 16... Main rope, 18... Load sensor, 19... Counterweight, 100... Inverter device, 101... Handle, 102, 103... Terminal section, 102U, 102V, 102W... Terminal, 103... Terminal section, 103U... Terminal, 104-U, 104-V, 104-W, 105-P, 105-N... Terminal, 107... Frame, 109... Control panel, 110 to 190... Parallel inverter, 111, 112, 121, 122, 131, 132, 141, 142... Inverter unit 111-C, 112-U1... capacitors, 111-F1, 111-F2, 111-F3... cooling fans, 111-U1, 111-U2, 111-V1, 111-V2, 111-W1, 111-W2... semiconductor switches, 190... inverter control device, 191... gate command unit, 192... trouble signal receiving unit, 193... trouble handling unit

Claims

1. An inverter control system in which parallel inverters, each of which is connected in parallel, are grouped into individual groups, and a plurality of parallel inverters are prepared for each group, and power is supplied to a motor that drives an elevator by the plurality of parallel inverters, and the parallel inverters of each group are controlled, a trouble signal receiving unit that receives an abnormality signal from the parallel inverters individually in units of the group; a gate command unit that, when the trouble signal receiving unit receives an abnormal signal from any of the groups, stops the parallel inverters of the group that received the abnormal signal and operates the parallel inverters of the group that did not receive the abnormal signal, The gate command unit restricts the number of passengers on the elevator depending on the number of groups for which the parallel inverters are operated. Inverter control system.

2. The trouble signal receiving unit stops the elevator when it receives abnormal signals from all groups. The inverter control system according to claim 1 .

3. An inverter control method in which a plurality of parallel inverters, each of which is connected in parallel, are grouped together into individual groups, and a plurality of parallel inverters are prepared for each group, and power is supplied to a motor that drives an elevator by the plurality of parallel inverters, thereby controlling the parallel inverters of each group, a trouble signal receiving process for individually receiving an abnormality signal of the parallel inverters in units of the group; and a control process for, when an abnormality signal of any of the groups is received in the trouble signal reception process, stopping the parallel inverters of the group that received the abnormality signal and operating the inverters of the group that did not receive the abnormality signal, and restricting the number of passengers on the elevator in accordance with the number of groups whose parallel inverters are operated. Inverter control method.

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