Arrangement and method for dynamic braking of permanent magnet motor and elevator using the same

Abstract

An arrangement (10) and method for dynamic braking of a permanent magnet motor (1), and an elevator (100) utilizing the same, are provided. The arrangement (10) includes a corresponding number of phase arms (4A-4C) and input connectors (3A-3C) relative to the number of a plurality of motor windings (2A-2C), wherein each of the input connectors (3A-3C) is coupled to a corresponding one of the phase arms (4A-4C). At least some of the phase arms (4A-4C) include at least two semiconductor devices (7A, 8A; 7B, 8B; 7C, 8C). Second terminals (42) of the phase arms (4A-4C) are connected to each other, wherein the arrangement (10) includes a plurality of semiconductor switches (5; 7A-7C; 8A-8C) configured to form a short circuit between each of the plurality of motor windings (2A-2C).

Description

Technical Field

[0001] The present invention relates generally to the technical field of electric motors. In particular, but not exclusively, the invention relates to a permanent magnet electric motor for an elevator for moving an elevator car, and to dynamic braking of the electric motor. Background Art

[0002] Dynamic braking of a permanent magnet motor is achieved by creating a short circuit condition between the motor's windings. By short-circuiting the windings, the motor's back electromotive force can be used to resist the motion of the rotor and thus be used for dynamic braking of the motor.

[0003] Dynamic braking is known to be achieved by using mechanical switches such as motor contactors. The contactors can be arranged to cause a short circuit between the motor windings, thereby inducing a back electromotive force that slows the motor. The contactors used for dynamic braking must be selected to withstand the motor current and be able to connect and / or disconnect this current. These contactors tend to be large and costly. In addition, the contactors, which include moving parts, have a certain limited lifespan and must be replaced after a relatively small number of operations.

[0004] In elevators, additional measures are required to brake the permanent magnet motor in certain situations. During maintenance, service technicians may need to manually operate the mechanical brake to lower the car without the electric drive to operate the motor. If the motor speed cannot be reduced, there is a risk of a sudden stop at high speed at the end point. In high-rise elevators, if the car stops in difficult locations such as express zones, the travel distance can be very long.

[0005] The combination of mechanical brakes and dynamic brakes can produce excessive deceleration which should be avoided. Main power failure or during an emergency stop at full speed are situations where the use of dynamic brakes should be considered.

[0006] Therefore, there is a need to develop solutions for dynamic braking of permanent magnet motors that are cheaper, fit into smaller spaces, and have a longer lifespan than existing solutions. Summary of the Invention

[0007] An object of the present invention is to provide an arrangement and a method for dynamic braking of a permanent magnet motor, and an elevator utilizing the same. Another object of the present invention is that the arrangement, the method and the elevator provide a reliable means for dynamic braking of a permanent magnet motor without requiring a mechanical switch and therefore without requiring moving parts.

[0008] The objects of the invention are achieved by an arrangement, a method and an elevator as defined in the respective independent claims.

[0009] According to a first aspect, an arrangement for dynamic braking of a permanent magnet motor comprising a plurality of motor windings is provided. The arrangement comprises a corresponding number of phase arms and input connectors relative to the number of the plurality of motor windings. Each of the input connectors is coupled to a respective one of the phase arms, and the second terminals of the phase arms are connected to each other. Each of the phase arms comprises at least two semiconductor devices connected in series, such as semiconductor diodes or switches. Each of the input connectors is connected between the at least two semiconductor devices connected in series, and the first terminals of the phase arms are connected to each other. The arrangement comprises a number of semiconductor switches configured to form a short circuit between each of the plurality of motor windings. The first terminal of the phase arm and the second terminal of the phase arm are further electrically connected to each other. Preferably, the short circuit can be arranged via a further electrical connection.

[0010] The term "semiconductor device" herein refers to a device that utilizes the properties of a semiconductor material. Specifically, a semiconductor device may be, but is not limited to, a semiconductor diode or a semiconductor switch. Furthermore, the semiconductor material whose properties are utilized may be, for example, silicon, silicon carbide, germanium, and gallium arsenide, or an organic semiconductor material.

[0011] The term "semiconductor switch" herein refers to a semiconductor device whose operation can be controlled, particularly with respect to conduction of current through the device. The semiconductor switch may specifically be, but is not limited to, a thyristor, a gate turn-off thyristor, an integrated gate-commutated thyristor (IGCT), an insulated gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET), a silicon carbide (SiC) MOSFET, a triac, a junction gate field effect transistor (JFET), or a SiC-JFET.

[0012] Furthermore, the two series-connected devices of the phase leg may be semiconductor switches configured to form a short circuit between the plurality of motor windings.

[0013] At least one of the two series-connected semiconductor devices in each of the phase legs may be one of several semiconductor switches configured to form a short circuit between the plurality of motor windings.

[0014] The at least two series connected semiconductor devices may be diodes, and a further electrical connection between the first and second terminals of the phase leg may be arranged through one of several semiconductor switches configured to form a short circuit between the plurality of motor windings.

[0015] The first and second terminals of the phase arm may be electrically connected to each other via a resistor or configured to be electrically connected to each other via a resistor, for example, connected in series with one or more of the semiconductor switches. The resistor and / or one or more of the semiconductor switches may preferably be arranged as a further electrical connection between the terminals of the phase arm.

[0016] Each of the two series-connected semiconductor devices may be one of the following types of devices: a diode, a thyristor, a gate turn-off thyristor, an integrated gate-commutated thyristor (IGCT), an insulated gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET), a silicon carbide (SiC) MOSFET, a bidirectional triode thyristor, a junction gate field effect transistor (JFET), or a SIC-JFET.

[0017] The several semiconductor switches may be one of the following types of semiconductor switches: thyristor, gate turn-off thyristor, integrated gate commutated thyristor (IGCT), insulated gate bipolar transistor (IGBT), metal oxide semiconductor field effect transistor (MOSFET), silicon carbide (SiC) MOSFET, bidirectional triode thyristor, junction gate field effect transistor (JFET), SiC-JFET.

[0018] According to another first aspect, an arrangement for dynamic braking of a permanent magnet motor comprising a plurality of motor windings is provided. The arrangement comprises a corresponding number of phase arms and input connectors relative to the number of the plurality of motor windings. Each of the input connectors is coupled to a respective one of the phase arms, and second terminals of the phase arms are connected to each other. At least a first number of phase arms comprise at least two anti-series-connected semiconductor switches having respective anti-parallel semiconductor devices coupled between first and second terminals of the phase arms, wherein the first number is one less than the number of the plurality of motor windings. The at least two anti-series-connected semiconductor switches having respective anti-parallel semiconductor devices of each of the phase arms comprising the switches are configured to form a short circuit between the plurality of motor windings.

[0019] The corresponding anti-parallel semiconductor device may be a separate semiconductor device connected anti-parallel to the semiconductor switch, such as a diode or an IGBT, or an intrinsic device anti-parallel to the semiconductor switch, such as in the case of a MOSFET semiconductor switch with an intrinsic freewheeling diode.

[0020] The first number of phase legs may preferably be the same as or at least the same as the number of the plurality of motor windings.

[0021] Each of the input connectors may be coupled between two anti-series-connected semiconductor switches having corresponding anti-parallel semiconductor devices.

[0022] Each of the input connectors may be coupled to a first terminal of a respective one of the phase legs.

[0023] Each of the input connectors may be coupled to a first terminal of a corresponding one of the phase legs, and a second terminal of the phase leg may be coupled to a neutral point (N) of the three-level inverter.

[0024] Furthermore, the corresponding anti-parallel connected semiconductor devices may be diodes or semiconductor devices. Thus, there may be a diode such as a freewheeling diode connected anti-parallel to the semiconductor switch of the phase arm, or another semiconductor switch anti-parallel to the semiconductor switch of the phase arm, thereby forming a bidirectionally conducting semiconductor switch device or arrangement.

[0025] According to a second aspect, a method for dynamic braking of a permanent magnet motor for an elevator in an emergency situation is provided. The permanent magnet motor includes a plurality of motor windings and is coupled to an elevator car of the elevator to move the elevator car. The method comprises:

[0026] - detect emergency situations, and

[0027] - Short-circuiting a plurality of motor windings by an arrangement according to any one of the first aspects.

[0028] According to a third aspect, an elevator is provided. The elevator comprises an arrangement according to any one of the first aspects and a permanent magnet motor comprising a plurality of motor windings. The permanent magnet motor is coupled to an elevator car and arranged to move the elevator car. The arrangement is coupled to the plurality of motor windings via an input connector of the arrangement. The elevator comprises an elevator control unit configured at least to detect an emergency condition of the elevator and control the arrangement to short-circuit the motor windings for dynamic braking of the motor.

[0029] The elevator may comprise an electric drive for operating the electric motor. The electric drive may be, for example, a frequency converter or an inverter, or in particular a three-level neutral point switching converter.

[0030] Normal operating conditions refer to conditions in which an elevator is servicing its landing floors in a normal manner. Emergency conditions refer to conditions such as a failure or loss of main power. Emergency conditions may also refer to conditions in which the elevator's safety circuit has been interrupted, thereby indicating a condition other than normal operating conditions.

[0031] The present invention provides an arrangement for dynamic braking of a permanent magnet motor, and a method for dynamic braking of a permanent magnet motor of an elevator, and an elevator therefor. The arrangement and method offer advantages over known solutions such that, when used in conjunction with an elevator, they extend the service life of the arrangement for dynamic braking, improve the reliability and safety of the elevator, and take up less space than known solutions for dynamic braking.

[0032] Various additional advantages will become apparent to skilled artisans based on the following detailed description.

[0033] The term "a number of" herein refers to any positive integer starting from one, such as one, two, three or four.

[0034] The term "a plurality of" herein refers to any positive integer starting from two, for example, to two, three or four.

[0035] The terms "first," "second," and "third" do not denote any order, quantity, or importance, but rather are used to distinguish one element from another.

[0036] The exemplary embodiments of the present invention presented here should not be interpreted as limiting the applicability of the appended claims. The verb "comprise" is used here as an open limitation that does not exclude the presence of unrecited features. Unless expressly stated otherwise, the features recited in the dependent claims may be freely combined with each other.

[0037] The novel features which are believed to be characteristic of the invention are set forth with particularity in the appended claims.The invention itself, however, both as to its organization and method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Embodiments of the invention are illustrated by way of example and not limitation in the figures of the accompanying drawings which are briefly described below.

[0039] Figure 1-9 Arrangements for dynamic braking of a permanent magnet motor according to various embodiments of the invention are schematically shown.

[0040] Figure 10 An elevator according to an embodiment of the invention is schematically shown.

[0041] Figure 11 A flow chart of a method according to an embodiment of the present invention is shown.

[0042] Figure 12 An elevator control unit according to an embodiment of the present invention is schematically shown. DETAILED DESCRIPTION

[0043] Figure 1-3 An arrangement 10 for dynamic braking of a permanent magnet motor 1 according to some embodiments of the present invention is shown. The arrangement 10 comprises a corresponding number of phase arms 4A-4C and input connectors 3A-3C relative to the number of motor windings 2A-2C, in which case the three phase arms 4A-4C and the three input connectors 3A-3C shown as the motor 1 are a three-phase permanent magnet motor 1. The input connectors 3A-3C can be coupled to or at least suitable for coupling to the motor windings 2A-2C. The arrangement 10 also comprises semiconductor devices 7A-7C, 8A-8C, in this case diodes 7A-7C, 8A-8C, however, they can also be, for example, semiconductor switches forming the three phase arms 4A-4C, unidirectionally or bidirectionally conducting semiconductor switching devices, wherein in Figure 1-3 Each phase leg 4A-4C includes two series-connected diodes 7A, 8A; 7B, 8B; 7C, 8C. The first terminals 41 of the phase legs 4A-4C are coupled to one another, and the second terminals 42 of the phase legs 4A-4C are coupled to one another. Furthermore, each input connector 3A-3C is coupled to one of the legs 4A-4C, specifically to a point between two series-connected diodes 7A, 8A; 7B, 8B; 7C, 8C. Diodes 7A, 8A; 7B, 8B; 7C, 8C thus form a three-phase diode bridge. The three-phase diode bridge rectifies the AC (alternating current) input voltage (i.e., the motor voltage) into a DC (direct current) voltage.

[0044] The arrangement 10 may further comprise a further electrical connection 6 between the first terminal 41 and the second terminal 42 of the phase leg. The arrangement 10 may further comprise a semiconductor switch 5, for example a unidirectional or bidirectionally conducting switching device such as a thyristor, a gate turn-off thyristor, an integrated gate-commutated thyristor (IGCT), an insulated gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET), a silicon carbide (SiC) MOSFET, a bidirectional triode thyristor, a junction gate field effect transistor (JFET) or a SiC-JFET, or such semiconductor switches connected in antiparallel, or any suitable semiconductor switching device arranged on the DC side of the diode bridge, preferably in the further electrical connection 6, for forming a short circuit between the first terminal 41 of the phase leg 4A-4C and the second terminal 42 of the phase leg 4A-4C via the further electrical connection. It should be noted that a bidirectionally conducting semiconductor switching device can be obtained by connecting two unidirectional switches in antiparallel to each other.

[0045] The terminals of semiconductor switch 5 can be coupled to first terminal 41 of phase leg 4A-4C and to second terminal 4A-4C of phase leg 4A-4C, i.e., in this case, connected in parallel with the diode bridge via further electrical connection 6. Semiconductor switch 5 can be controlled by applying a control signal, such as a voltage or current, to a control terminal, such as a gate terminal, of semiconductor switch 5. As known to those skilled in the art, the control method depends on the type of semiconductor switch. For example, as known to those skilled in the art, a thyristor can be controlled to conduct current by applying a current to its gate. An IGBT can be controlled by applying a suitable voltage to its gate terminal.

[0046] By placing semiconductor switch 5 in a conductive state, switch 5 can be arranged to create a short-circuit condition between motor windings 2A-2C, thereby achieving dynamic braking of motor 1. A resistor 9, such as a braking resistor 9, may also be present in series with switch 5, in which case one terminal of switch 5 is coupled to a terminal of resistor 9. By utilizing resistor 9, the short-circuit current can be reduced compared to a direct short-circuit condition. This further reduces the load on motor 1 during a short-circuit condition compared to a direct short-circuit condition. In some embodiments, such as those utilizing thyristors 5, switch 5 can only be switched to a conductive state, while switching it back to a non-conductive state is not possible. However, in some embodiments, such as those utilizing controllable switching devices such as IGBTs, switch 5 can be controlled to a non-conductive state, thereby eliminating the short-circuit condition between motor windings 2A-2C and enabling dynamic braking when desired.

[0047] Therefore, one can Figure 1-3 The arrangement 10 shown in FIG. 1 achieves dynamic braking by arranging the semiconductor switch 5 to a conducting state permanently, or at least during the time that dynamic braking occurs, thereby providing a short circuit condition to the motor windings 2A-2C (either directly or through a resistor 9).

[0048] and Figure 1-3 , more than two semiconductor devices 7A-7C, 8A-8C may be included in each of the phase arms 4A-4C. For example, one or more of the phase arms 4A-4C may include four semiconductor devices. For example, the semiconductor devices 7A-7C, 8A-8C may be arranged so that there are two sets of parallel-connected diodes between which the input connectors 3A-3C are coupled. Alternatively, for example, there may be four series-connected diodes between two of which the input connectors 3A-3C are coupled. All semiconductor devices 7A-7C, 8A-8C and the input connectors 3A-3C are preferably connected between the terminals 41, 42 of the phase arms 4A-4C.

[0049] Figure 1-3Further shown is an electric drive 105 that can be used to operate or drive the permanent magnet motor 1. The electric drive 105 can be, for example, a frequency converter or an inverter. There can also be a filter (not shown) connected to the input and / or output of the electric drive 105 for filtering at least some frequency components of the current and / or voltage on the input or output side of the electric drive 105. The electric drive 105 can preferably be communicatively coupled to the elevator control unit 1000 ( Figure 1-3 (not shown). Similar electric drive 105 can also be used in Figure 4-8 In the embodiment shown in FIG, however, different kinds of drivers 105 may also be used.

[0050] Figure 4 and 5 An arrangement 10 for dynamic braking of a permanent magnet motor 1 according to some embodiments of the present invention is shown. The arrangement 10 comprises a corresponding number of phase arms 4A-4C and input connectors 3A-3C relative to the number of motor windings 2A-2C, in this case three phase arms 4A-4C and three input connectors 3A-3C shown as a motor 1 being a three-phase permanent magnet motor 1. The input connectors 3A-3C may be coupled to or at least may be adapted to be coupled to the motor windings 2A-2C. The arrangement 10 also comprises a plurality of phase arms 4A-4C and input connectors 3A-3C in accordance with the embodiment of the present invention. Figure 1-3 The six semiconductor devices are arranged similarly to the diodes in the embodiment, i.e., two in each of the phase legs 4A-4C, however, three of the diodes have been replaced by semiconductor switches such as unidirectional semiconductor switches, such as thyristors or bidirectional switches, such as IGBTs, or a combination thereof. Figure 4 An arrangement 10 utilizing thyristors is shown in FIG. Figure 5 An arrangement 10 utilizing IGBTs is shown in FIG. However, it should be noted that although Figure 4 and Figure 5 While the lower semiconductor devices 8A-8C are shown as being replaced by semiconductor switches, the upper semiconductor devices 7A-7C may be replaced by switches, or two of the lower semiconductor devices 7A-7C may be semiconductor switches and one of the upper semiconductor devices 8A-8C may be a semiconductor switch, or any combination thereof. Alternatively, all semiconductor devices 7A-7C and 8A-8C may be semiconductor switches, or both of the two series-connected semiconductor switches 7A, 8A; 7B, 8B; and 7C, 8C in one or more phase legs 4A-4C may be semiconductor switches. This provides the advantage of fully controlling the dynamic braking of motor 1 using semiconductor switches.

[0051] exist Figure 4 and Figure 5 In the embodiment of FIG, each phase leg 4A-4C comprises a series connection of two semiconductor devices 7A-7C, 8A-8C. The two components may be a diode and a semiconductor switch. Figure 4 and Figure 5 In the embodiment, the second terminals of diodes 7A-7C are coupled to one another, and the first terminals 71 of diodes 7A-7C are coupled to the second terminals 82 of semiconductor switches 8A-8C, respectively. The first terminals 41 of phase arms 4A-4C are coupled to one another, and the second terminals 42 of phase arms 4A-4C are coupled to one another. Furthermore, each input connector 3A-3C is coupled to one of the phase arms 4A-4C, specifically to a point between the diodes 7A-7C and the semiconductor switches 8A-8C of the phase arm 4A-4C. The semiconductor switches 8A-8C may be, for example, thyristors, gate turn-off thyristors, IGCTs, IGBTs, MOSFETs, SiC-MOSFETs, triacs, JFETs, SiC-JFETs, or any other suitable semiconductor switching device, or any combination thereof, for short-circuiting the motor windings.

[0052] In addition, Figure 4 and Figure 5 In the embodiment, the first terminal 41 of the phase leg 4A-4C is coupled by a further electrical connection 6 directly to a second terminal 42 of the phase leg 4A-4C or alternatively via a resistor 9 to obtain a short circuit condition.

[0053] Therefore, one can Figure 4 and Figure 5 The arrangement 10 shown in FIG. 1 achieves dynamic braking by arranging the semiconductor switches 8A-8C to a conductive state permanently, or at least during the time that dynamic braking occurs, thereby providing a short circuit condition for the motor windings 2A-2C (either directly or through a resistor 9).

[0054] Figure 6 Schematically, an arrangement 10 for dynamic braking of a permanent magnet motor 1 according to an embodiment of the present invention is shown. The arrangement 10 comprises a corresponding number of phase arms 4A-4C and input connectors 3A-3C relative to the number of motor windings 2A-2C, in this case three phase arms 4A-4C and three input connectors 3A-3C shown as a motor 1 being a three-phase permanent magnet motor 1. The input connectors 3A-3C can be coupled to or at least can be adapted to be coupled to the motor windings 2A-2C. The arrangement 10 also comprises a plurality of phase arms 4A-4C and input connectors 3A-3C corresponding to the number of motor windings 2A-2C. Figure 1-3 The six semiconductor devices are arranged in a similar arrangement to the diodes in FIG. 5 , however, in this case, the diodes have been replaced by semiconductor switches, specifically bidirectional conducting switching devices, such as IGBTs with anti-parallel connected diodes (i.e., freewheeling diodes), or any other suitable bidirectional conducting switching devices. Furthermore, in contrast to FIG. 5 , Figure 6 , the semiconductor devices of phase legs 4A-4C are connected in an anti-series connection.

[0055] According to an embodiment of the present invention, the bidirectionally conducting semiconductor switching devices of each of the phase legs 4A- 4C may be connected in series.

[0056] According to Figure 6 In the embodiment of the present invention shown, the switches 7A-7B, 8A-8B of each of the two series-connected switches 7A-7B, 8A-8B are connected in anti-series with respect to each other, i.e., the first terminal 71 or the second terminal 72 of one switch 7A-7B, 8A-8B is connected to the first terminal 81 or the second terminal 82 of the other switch, respectively. It should be noted that a bidirectionally conducting switching device or arrangement can be obtained by connecting two unidirectionally conducting semiconductor switches in anti-parallel with each other.

[0057] exist Figure 6 In the embodiment of the present invention, first terminals 41 of phase legs 4A-4C are coupled to one another, and second terminals 42 of phase legs 4A-4C are coupled to one another. Furthermore, each input connector 3A-3C is coupled to one of the legs 4A-4C, specifically to a point between two anti-series-connected semiconductor switches 7A, 8A; 7B, 8B; 7C, 8C. The switches may be, for example, IGBTs, MOSFETs, SiC-MOSFETs, triacs, JFETs, SiC-JFETs, or any other suitable semiconductor switching device, or a combination thereof, for short-circuiting the motor windings.

[0058] Therefore, one can Figure 6 The arrangement 10 shown in FIG. 1 or a similar arrangement 10 having anti-series connected semiconductor switches 7A-7C, 8A-8C, achieves dynamic braking by arranging the semiconductor switches 7A-7C, 8A-8C to a conductive state permanently or at least during the time that dynamic braking occurs, wherein the anti-series connected semiconductor switches have corresponding anti-parallel semiconductor devices, such as diodes or semiconductor switches, thereby providing a short-circuit condition for the motor windings 2A-2C. Because the anti-series connected switching devices are bidirectionally conductive switching devices, there is no need to arrange a separate short-circuit path or conductor, i.e., such as in FIG. Figure 1-5 In the case of the arrangement shown in , further electrical connections 6 are provided.

[0059] Figure 7An arrangement 10 for dynamic braking of a permanent magnet motor 1 according to an embodiment of the invention is shown. The arrangement 10 comprises a corresponding number of phase arms 4A-4C and input connectors 3A-3C relative to the number of motor windings 2A-2C, in this case the three-phase arms 4A-4C and the three input connectors 3A-3C shown as the motor 1 being a three-phase permanent magnet motor 1. The input connectors 3A-3C may be coupled to or at least may be suitable for being coupled to the motor windings 2A-2C. The arrangement 10 further comprises four semiconductor switches 7A-7B, 8A-8B having corresponding anti-parallel semiconductor devices (e.g. IGBTs with corresponding anti-parallel freewheeling diodes), for example two anti-series connected semiconductor switches in two of the three-phase arms 4A-4C, i.e. one less than the number of motor windings 2A-2C. As in Figure 7 As can be seen in FIG, in order to achieve the desired dynamic braking effect, the semiconductor switches 7A-7B, 8A-8B of each of the two anti-series-connected semiconductor switches 7A-7B, 8A-8B are anti-series-connected with each other, that is, the first terminal 71 or the second terminal 72 of one switch 7A-7B, 8A-8B is connected to the first terminal 81 or the second terminal 82 of the other switch, respectively. The semiconductor switches 7A-7B, 8A-8B are omitted from the third phase leg, and when the semiconductor switches of the other two phase legs are in the on state, it provides a short-circuit condition for the third motor winding.

[0060] Figure 8 An arrangement 10 for dynamic braking of a permanent magnet motor 1 according to an embodiment of the invention is shown. The arrangement 10 comprises a corresponding number of phase arms 4A-4C and input connectors 3A-3C relative to the number of motor windings 2A-2C, in this case the three phase arms 4A-4C and the three input connectors 3A-3C shown as the motor 1 being a three-phase permanent magnet motor 1. The input connectors 3A-3C may be coupled to or at least may be suitable for being coupled to the motor windings 2A-2C. The arrangement 10 further comprises six semiconductor devices 7A-7C, 8A-8C having corresponding anti-parallel semiconductor devices (e.g. IGBTs), for example two anti-series connected semiconductor switches in each of the phase arms 4A-4C having corresponding anti-parallel semiconductor devices. As in Figure 8 As can be seen in the figure, in order to achieve the desired dynamic braking effect, the switches 7A-7C, 8A-8C of each of the two series-connected switches are connected in anti-series with each other, that is, the first terminal 71 or the second terminal 72 of one switch is connected to the first terminal 81 or the second terminal 82 of the other switch, respectively.

[0061] Therefore, one can Figure 7 and Figure 8The arrangement 10 shown implements dynamic braking by arranging the semiconductor switches to a conducting state, either permanently or at least for the time that dynamic braking occurs, thereby providing a short circuit condition to the motor windings 2A-2C.

[0062] Figure 9 An arrangement 10 for dynamic braking of a permanent magnet motor 1 according to an embodiment of the present invention is shown. Figure 9 In the embodiment, the electric drive 105 is a three-level inverter, specifically a three-level neutral point switch 2 (3L-NPC2) inverter. However, it should be noted that there are various three-level neutral point switch inverters known to those skilled in the art. According to this embodiment, the neutral point switch can be used for dynamic braking of the motor 1. It can be seen that the neutral point switch utilizes the same Figure 8 The arrangement shown is similar to the one shown, except that the short-circuit terminal of the semiconductor switching device or arrangement of each phase leg is also connected to the neutral point of the three-level inverter. Thus, there are two bidirectionally conducting anti-series connected switching devices (e.g., of the type mentioned above) in each phase leg of the neutral point switch.

[0063] The electrical power for operating the neutral point switch can be taken from an energy storage device, for example from the input capacitor of a 3L-NPC2 inverter or from an intermediate circuit of an electric drive 105 such as a frequency converter. For example, the energy storage device can be charged by regenerative braking of the electric motor 1.

[0064] Therefore, one can Figure 9 The arrangement 10 shown implements dynamic braking by arranging the semiconductor switches to a conducting state permanently, or at least during the time that dynamic braking occurs, thereby providing a short-circuit condition for the motor windings 2A-2C. During this time, the other switches of the frequency converter or inverter are preferably arranged to be in a non-conducting state.

[0065] about Figure 1-9 In each of the embodiments of the present invention shown in FIG, the dynamic braking arrangement 10 can be advantageously used in an elevator 100, for example, in an emergency situation such as a loss of main power or an emergency stop situation. In an emergency situation, the electric drive 105 seizes the opportunity to modulate its switches, and the switches of the arrangement 10 can be switched to a conducting state to provide dynamic braking, i.e., dynamic braking by creating a short circuit condition between the motor windings 2A-2C. Specifically, in FIG. Figure 9 In the case of the embodiment shown, modulation or switching of the other switches of the inverter is stopped while the switch of the neutral point switch can be switched to the on state permanently or at least for the time when dynamic braking occurs, thereby providing a short circuit condition for the motor windings 2A-2C.

[0066] Figure 10An elevator 100 according to an embodiment of the present invention is schematically shown. The elevator 100 may include a permanent magnet motor 1 for moving an elevator car 130 included in the elevator 100. The elevator car 130 may be mechanically coupled to the motor 1, for example, via a hoisting device 140, such as a rope 140, or via hydraulic means. The operation of the motor 1 may be controlled by an electric drive 105, such as a frequency converter 105 or an inverter 105.

[0067] The lifting device 140 may comprise, for example, steel fibers or carbon fibers. In any case, the term "lifting device" does not limit the form of the element. For example, the lifting rope 140 may be implemented as a rope or a belt.

[0068] The elevator 100 preferably further comprises an elevator brake 20, for example an electromechanical brake 20. The elevator brake 20 may comprise components such as a brake caliper and / or a brake drum. In addition, the brake 20 may comprise electronic devices for operating the brake 20, i.e., for activating and / or deactivating the brake 20.

[0069] The elevator 100 may include an elevator control unit 1000 for controlling the operation of the elevator 100. The elevator control unit 1000 may be a separate device or may be included in other components of the elevator 1000, for example in the elevator 1000 or as a part of the elevator 1000. The elevator control unit 1000 may also be implemented in a distributed manner, so that, for example, part of the elevator control unit 1000 may be included in the electric drive 105 and another part may be included in the elevator car 130. The elevator control unit 1000 may also be arranged in a distributed manner in more than two locations or in more than two devices.

[0070] The elevator 100 may include an arrangement 10 for dynamic braking of the motor 1. The arrangement 10 is preferably coupled to the motor windings 2A-2C of the motor 1 close to the motor 1 so that the arrangement 10 can be used to effectively short-circuit the motor windings 2A-2C. Preferably, no additional components or equipment are coupled between the arrangement 10 and the motor 1.

[0071] Normal operating conditions refer to conditions in which the elevator 100 is servicing its landings in a normal manner. Emergency conditions refer to conditions such as a failure or loss of the main power supply 125. Emergency conditions may also refer to conditions in which the safety circuits of the elevator 100 have been interrupted, thereby indicating a condition other than normal operating conditions. For example, emergency conditions may be detected by measuring the voltage level of the main power supply 125, the input or output voltage of the electric drive 105, or the input of the arrangement 10 for dynamic braking of the motor 1.

[0072] In the embodiments of the present invention, the Figure 10Other elements shown in the figure are a main power source 125 such as a three-phase or single-phase electrical network, the electrical connections of the arrangement 10 (i.e., input connectors 3A-3B), and a connection 165 between the electric drive 105 and the motor 1. The elevator car 130 can operate in a hoistway 145 serving landing floors 160. A counterweight 135 may or may not be utilized in embodiments of the present invention.

[0073] Figure 11 A flow chart of a method according to an embodiment of the present invention is shown.

[0074] Step 1100 refers to the startup phase of the method. Appropriate equipment and components are obtained, and the system is assembled and configured for operation.

[0075] At 1110, an emergency condition (if any) of the elevator 100 may be being detected. The detection 1110 may be based on a measured voltage of the main power supply 125, a voltage (input or output voltage) of the electric drive 105, or in response to a safety circuit related event, or may be obtained from another source communicatively coupled to the elevator control unit 1000.

[0076] At 1120, the motor windings 2A-2C are short-circuited using an embodiment of the arrangement 10 as previously described. The arrangement 10 may be such as in combination with Figure 1-9 Any one of the arrangements shown and described, or some other kind of arrangement 10 within the scope of the present invention.

[0077] Once the motor windings 2A-2C have been short-circuited and the elevator car 130 is moving, a short-circuit current flows through the arrangement 10. At least the semiconductor switches necessary to form the short circuit can then preferably be continuously or permanently in the on state in order to provide dynamic braking of the motor 1. The elevator car 130 can then be brought to a complete stop and secured in the desired position by activating the elevator brake 20.

[0078] The method execution is stopped at step 1199. The method can be repeated continuously, intermittently or on demand. Preferably, the method can be implemented during an emergency situation of the elevator 100. The method enhances the reliability and safety of the elevator 100 relative to known solutions.

[0079] Figure 12The elevator control unit 1000 according to an embodiment of the present invention is schematically shown. An external unit 701 can be connected to a communication interface 708 of the elevator control unit 1000. The external unit 701 can include a wireless connection or a wired connection. The communication interface 708 provides the elevator control unit 1000 with an interface for communicating with the external unit 701, such as the elevator car 130, the motor 1, the door of the landing floor 160, or the electric drive 105. It can also be connected to an external system, such as a laptop or handheld device. There can also be a connection to a database of the elevator 1000 or an external database containing information for controlling the operation of the elevator 1000.

[0080] The elevator control unit 1000 may include one or more processors 704, one or more volatile or non-volatile memories 706 for storing parts of the computer program code 707A-707N and any data values, and possibly one or more user interface units 710. The elements may be communicatively coupled to each other using, for example, an internal bus.

[0081] The processor 704 of the elevator control unit 1000 is configured to implement at least some of the method steps described above. The method can be implemented by arranging the processor 704 to execute at least a portion of the computer program code 707A-707N stored in the memory 706, such that the processor 704 and the elevator control unit 1000 implement, for example, one or more of the method steps described, but not necessarily all of them, and not limited to detecting an emergency condition and controlling the semiconductor switch of step 10 to enter a conductive state that short-circuits the motor windings 2A-2C. Thus, the processor 704 is arranged to access the memory 706 and retrieve any information therefrom, as well as store any information therein. For clarity, the processor 704 herein refers to any unit suitable for processing information and controlling the operation and other tasks of the elevator control unit 1000. A microcontroller solution with embedded software can also be used to implement the operations. Similarly, the memory 706 is not limited to a specific type of memory; rather, any memory type suitable for storing the described information is applicable within the context of the present invention.

[0082] The specific examples provided in the description given above should not be construed as limiting the applicability and / or interpretation of the appended claims.The lists and groups of examples provided in the description given above are not exhaustive unless expressly stated otherwise.

Claims

1. An arrangement (10) for dynamic braking of a permanent magnet motor (1) comprising a plurality of motor windings (2A-2C), wherein the arrangement (10) comprises a corresponding number of phase arms (4A-4C) and input connectors (3A-3C) relative to the number of the plurality of motor windings (2A-2C), wherein each of the input connectors (3A-3C) is coupled to a corresponding one of the phase arms (4A-4C), and second terminals (42) of the phase arms (4A-4C) are connected to each other, It is characterized in that Each of the phase arms (4A-4C) includes at least two anti-series-connected semiconductor switches (7A, 8A; 7B, 8B; 7C, 8C) having corresponding anti-parallel semiconductor devices coupled between a first terminal (41) and a second terminal (42) of the phase arm (4A-4C), wherein the at least two anti-series-connected semiconductor switches (7A, 8A; 7B, 8B; 7C, 8C) having corresponding anti-parallel semiconductor devices of each of the phase arms (4A-4C) including the switches (7A, 8A; 7B, 8B; 7C, 8C) are configured to form a short circuit between the plurality of motor windings (2A-2C).

2. The arrangement (10) of claim 1, wherein each of the input connectors (3A-3C) is coupled between the two anti-series connected semiconductor switches (7A, 8A; 7B, 8B; 7C, 8C) having respective anti-parallel semiconductor devices.

3. The arrangement (10) of claim 1, wherein each of the input connectors (3A-3C) is coupled to a first terminal (41) of a respective one of the phase legs (4A-4C).

4. The arrangement (10) of claim 1, wherein each of the input connectors (3A-3C) is coupled to a first terminal (41) of a respective one of the phase legs (4A-4C), and a second terminal (42) of the phase leg (4A-4C) is coupled to a neutral point (N) of the three-level inverter.

5. The arrangement (10) according to any one of claims 1 to 4, wherein the respective anti-parallel connected semiconductor devices are diodes or semiconductor switches.

6. A method for dynamic braking of a permanent magnet motor (1) of an elevator (100) in an emergency situation, wherein the permanent magnet motor (1) comprises a plurality of motor windings (2A-2C) and is coupled to an elevator car (130) of the elevator (100) for moving the elevator car (130), characterized in that The method comprises: - detecting (1110) an emergency situation, and - Short-circuiting (1120) the plurality of motor windings (2A-2C) by an arrangement (10) according to any one of claims 1-5.

7. An elevator (100), characterized in that: The elevator (100) comprises an arrangement (10) according to any one of claims 1 to 5 and a permanent magnet motor (1) comprising a plurality of motor windings (2A-2C) and an elevator control unit (1000), wherein the permanent magnet motor (1) is coupled to an elevator car (130) and is arranged to move the elevator car (130), and the arrangement (10) is coupled to the plurality of motor windings (2A-2C) via input connectors (3A-3C), and the elevator control unit (1000) is configured to at least detect an emergency situation of the elevator (100) and control the arrangement (10) to short-circuit the motor windings (2A-2C) for dynamic braking (1) of the motor.

8. Elevator (100) according to claim 7, comprising an electric drive (105) for operating the electric motor (1).

9. The elevator (100) according to claim 8, wherein the electric drive (105) is a three-level neutral point switching converter.

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