Methods for determining the rotor position of an electric motor, elevators, and electric converter units.

Abstract

A method, an elevator (100), and an electric converter unit (14) for determining the rotor position of an electric motor (12) are proposed. The method includes: supplying (41) a first excitation signal (ES1) to the electric motor (12); determining (42) a first response signal (RS1) generated in the electric motor (12) in response to the first excitation signal (ES1); determining (43) an electrical angle of the direct axis (D, -D, +D) of the motor (12) relative to a stationary reference frame based on the first response signal (RS1); supplying (44) a second excitation signal (ES2) to the motor (12), wherein the second excitation signal (ES2) is based on the determined electrical angle; determining (45) a second response signal (RS2) generated in the motor (12) in response to the second excitation signal (ES2); and determining (46) the rotor position based on the second response signal (RS2).

Description

Technical Field

[0001] This invention generally relates to electric motors. Specifically, but not exclusively, this invention relates to determining the rotor position of an elevator motor. Background Technology

[0002] There are known solutions for determining the rotor position of an electric motor. In some solutions, a resolver has been attached to the rotor to measure its absolute position. However, this increases the number of components and requires space for the resolver.

[0003] According to another known solution, the rotor position is determined using a frequency converter connected to the motor. In this solution, a load bridge with the converter is installed to supply a first AC voltage excitation signal to the electric motor. A current sensor measures the current in the stator windings of the electric motor generated by the supplied AC voltage excitation signal. The measured current forms a first AC current response signal corresponding to the supplied first AC voltage excitation signal, and the rotor position of the electric motor is determined based on the determined first AC current response signal.

[0004] However, problems arise when the excitation signal causes the rotor to move. For example, in an elevator, this would mean the elevator car would also move, potentially causing undesirable situations for passengers inside, entering, or leaving the car. In these cases, rotor position determination may fail. To avoid failure, the brakes used to hold the rotor in its position must be enlarged, increasing costs. Furthermore, the excitation signal introduces noise and mechanical vibration into the system. Therefore, a solution for determining the rotor position of an electric motor remains to be developed. Summary of the Invention

[0005] The object of this invention is to provide a method, elevator, and electric converter unit for determining the rotor position of an electric motor. Another object of this invention is that the method, elevator, and electric converter unit minimize the forces causing rotor movement during rotor position determination, and thus minimize the forces required, such as those required to hold the rotor in its position by means of a brake.

[0006] The object of the present invention is achieved by the method, elevator, and electric converter unit as defined in the individual claims.

[0007] According to a first aspect, a method is provided for determining the rotor position of an electric motor, such as an elevator. The method includes:

[0008] - Supply the first excitation signal to the electric motor.

[0009] - Determine the first response signal generated in the electric motor in response to the first excitation signal.

[0010] - Based on the first response signal, determine the electrical angle of the electric motor's direct axis relative to a stationary reference frame, such as the electrical angle with respect to the electric motor's stator.

[0011] - A second excitation signal is supplied to the electric motor, wherein the second excitation signal is based on the determined electrical angle.

[0012] - Determine the second response signal generated in the electric motor in response to the second excitation signal, and

[0013] - Determine the rotor position based on the second response signal.

[0014] In some embodiments, the first excitation signal may be, for example, a first AC voltage signal with a constant amplitude, and the first response signal may be a first response current generated in response to the first AC voltage signal; or / and the second excitation signal may be, for example, a second AC voltage signal with a constant amplitude, and the second response signal may be a second response current generated in response to the second AC voltage signal.

[0015] Alternatively, the first excitation signal may be, for example, a first alternating current signal with a constant amplitude, and the first response signal may be a first response voltage generated in response to the first alternating current signal; or / and the second excitation signal may be, for example, a second alternating current signal with a constant amplitude, and the second response signal may be a second response voltage generated in response to the second alternating current signal.

[0016] In the embodiments, the first excitation signal and the second response signal can be voltage or current signals, respectively, and the second excitation signal and the first response signal can be current or voltage signals.

[0017] In various embodiments, the method may include: applying a force of a first amount to hold the engine rotor in its position, at least before the supply of the first excitation signal and during the determination of the first response signal, wherein the first amount is related to the direction of the movement of the rotor.

[0018] In various embodiments, the first excitation signal may include an AC excitation signal, such as voltage or current, continuously supplied inside the electric motor to generate a rotating field in one direction and another AC excitation signal, such as voltage or current, to generate a rotating field in the opposite direction.

[0019] In various embodiments, determining the electrical angle may include determining the electrical angle of the first excitation signal when the maximum amount of the first response signal occurs.

[0020] In various embodiments, determining the rotor position may include comparing the maximum value of the second response signal to determine the positions of the rotor's south and north poles.

[0021] In various embodiments, the second excitation signal can be configured to be supplied by gradually increasing its amplitude in order to avoid stepwise changes in the force generated in the engine.

[0022] In various embodiments, the electric motor is an elevator motor of an elevator, wherein the elevator includes at least one elevator brake for braking the motor, and wherein the method may include applying force through at least one elevator brake.

[0023] In various embodiments, the force generated by the first excitation signal to move the rotor may be less than a first amount, such that the rotor maintains its position during the supply of the first excitation signal.

[0024] In various embodiments, the electric motor can be one of the following: a synchronous reluctance motor, a permanent magnet motor, a permanent magnet linear motor, a permanent magnet assisted synchronous reluctance motor, or a linear switched reluctance motor.

[0025] According to a second aspect, an elevator is provided. The elevator includes an elevator car, an elevator motor configured to move the elevator car, an electric converter unit for operating the elevator motor, at least one elevator brake, and a control unit configured to at least perform the method according to the first aspect or any embodiment thereof.

[0026] Therefore, the control unit can be configured to cause the elevator, preferably its electrical converter unit:

[0027] - Supply a first excitation signal to the elevator motor, such as a first excitation voltage or current signal.

[0028] - Determine a first response signal, such as a first response current or voltage, generated in the elevator motor in response to the first excitation signal;

[0029] - Based on the first response signal, determine the electrical angle of the electric motor's direct axis relative to a stationary reference frame, such as the electrical angle with respect to the electric motor's stator.

[0030] - A second excitation signal, such as a second excitation voltage or current signal, is supplied to the electric motor, wherein the second excitation signal is based on a determined electrical angle.

[0031] - Determine a second response signal, such as a second response current or voltage, generated in the electric motor in response to the second excitation signal, and

[0032] - The rotor position is determined based on the second response current.

[0033] In various embodiments, the control unit may also be configured to cause at least one elevator brake to:

[0034] - At least during the supply of the first excitation signal and the determination of the first response signal, a force of a first amount is applied to hold the engine rotor in its position, for example, to lock it in its position, wherein the first amount is in the direction of resisting the movement of the rotor.

[0035] In some embodiments, determining the electrical angle may include determining the electrical angle of the first excitation signal when the maximum amount of the first response signal occurs.

[0036] In some embodiments, determining the rotor position may include comparing the maximum value of the second response signal to determine the positions of the rotor's south and north poles.

[0037] According to a third aspect, an electrical converter unit is provided. This electrical converter unit is configured to perform at least the method according to the first aspect or any embodiment thereof.

[0038] Therefore, the electrical converter unit can be configured to at least:

[0039] - Supply a first excitation signal to the elevator motor, such as a first excitation voltage or current signal.

[0040] - Determine a first response signal, such as a first response current or voltage, generated in the elevator motor in response to the first excitation signal;

[0041] - Based on the first response signal, determine the electrical angle of the electric motor's direct axis relative to a stationary reference frame, such as the electrical angle with respect to the electric motor's stator.

[0042] - A second excitation signal, such as a second excitation voltage or current signal, is supplied to the electric motor, wherein the second excitation signal is based on a determined electrical angle.

[0043] - Determine a second response signal, such as a second response current or voltage, generated in the electric motor in response to the second excitation signal, and

[0044] - Determine the rotor position based on the second response signal.

[0045] In various embodiments, the electric converter unit may include converter devices such as frequency converters or inverters, and current determination components and / or voltage determination components for determining at least a first response signal and a second response signal.

[0046] This invention offers advantages over known solutions. During the supply of the excitation signal in the rotor position determination process, the rotor is easily held in its position, or at least can be easily held in its position. Minimizing the forces causing rotor movement and thus the forces required to hold the rotor in its position during rotor position determination allows for the use of smaller braking forces and therefore allows for the use of smaller brakes or less frequent brake application. This is particularly advantageous, for example, in elevators in which an engine is arranged to move the elevator car. Therefore, the elevator car does not move during rotor position determination. Movement can be unpleasant for passengers inside the car. Furthermore, compared to known solutions that utilize one or more excitation signals to determine the rotor position, the excitation signals induce less noise and vibration in the engine.

[0047] Based on the following detailed description, various other advantages will become clear to those skilled in the art.

[0048] The expression “several” here can refer to any positive integer starting from one (1), that is, at least one.

[0049] The expression “multiple” can refer to any positive integer starting from two (2), that is, at least two.

[0050] Unless otherwise explicitly stated, the terms “first,” “second,” and “third” are used here to distinguish one element from another, without specifically assigning them a priority or order.

[0051] The exemplary embodiments of the invention presented herein should not be construed as limiting the applicability of the appended claims. The verb "comprising" is used herein as an open-ended limitation, which does not exclude the presence of features not described. Unless otherwise expressly stated, the features described in the dependent claims may be freely combined with each other.

[0052] The appended claims specifically set forth novel features that are considered characteristic of the invention. However, the invention itself, in conjunction with its additional objects and advantages, both in its structure and its method of operation, will be best understood when read in conjunction with the accompanying drawings and from the following description of specific embodiments. Attached Figure Description

[0053] The accompanying drawings illustrate certain embodiments of the invention by way of example and not limitation.

[0054] Figures 1A to 1C An electrical converter unit according to certain embodiments of the present invention is illustrated schematically.

[0055] Figure 2 An elevator according to an embodiment of the present invention is illustrated schematically.

[0056] Figure 3 An elevator according to an embodiment of the present invention is illustrated schematically.

[0057] Figure 4 A flowchart of a method according to an embodiment of the present invention is shown.

[0058] Figure 5A and Figure 5B Examples of first and second response signals according to embodiments of the present invention are illustrated schematically.

[0059] Figure 6A and Figure 6B An electrical converter unit according to certain embodiments of the present invention is illustrated schematically. Detailed Implementation

[0060] Figure 1A An electric converter unit 14 according to an embodiment of the present invention is schematically shown. The electric converter unit 14 may include a frequency converter or inverter, or specifically, one or more power conversion circuits 14B thereof. Furthermore, the electric converter unit 14 may include a current determination component 14C and / or a voltage determination component (not shown) to determine one or more currents flowing into or out of the electric motor 12, such as three instantaneous phase currents, or voltages present between motor phases or between motor phases and ground / reference / neutral potentials such as a star point of the motor 12. The current determination component 14C and / or the voltage determination component may preferably be arranged to connect to a control unit 14A to provide information about the one or more currents / voltages to the control unit 14A. Preferably, the electric converter unit 14 may be configured to control the one or more currents / voltages at least under normal operating conditions to control the operation of the motor 12, such as the rotation or movement of the rotor of the motor 12.

[0061] Furthermore, the power converter unit 14 may include a control unit 14A, which is closely arranged with a converter device 14D, such as a frequency converter or inverter, including one or more power conversion circuits 14B therein, for example, within the same housing. External connections 15 may also be arranged to the power converter unit 14 to provide, for example, one or more measurement, one or more control signals, and / or power from external systems connected to or specifically connected to its control unit 14A. These external systems may be, for example, vehicles, industrial processes, or other similar systems. Figure 2 and Figure 3 The elevator shown.

[0062] Figure 1B An electrical converter unit 14 according to an embodiment of the present invention is shown schematically. Figure 1BThe converter unit 14 in the middle is similar in other respects to the one mentioned above. Figure 1A The illustrated and described electrical converter unit, except that the control unit 14A is arranged separately from the converter device 14D, for example, the control unit 14A is arranged outside the housing of the converter device 14D. Therefore, only the control unit 14A can be arranged to be connected to one or more conversion circuits 14B. The control unit 14A can, for example, be part of a control unit of an external system including the electrical converter unit 14.

[0063] Figure 1C An electrical converter unit 14 according to an embodiment of the present invention is schematically shown. Figure 1C In this circuit, the power converter unit 14 may include a frequency converter having an energy storage device 24, such as a capacitor (bank) or a battery, arranged on its intermediate circuit 23, or at least connected to the intermediate circuit 23 in the case of a battery. The frequency converter may be arranged to supply power between the power grid 20 and the electric motor 12. The frequency converter may include a load bridge 22 connected to the electric motor 12 to supply power between the electric motor 12 and the load bridge 22. The load bridge 22 may include controllable solid-state switches to form, for example, a power conversion circuit for a three-phase two-level or three-phase three-level inverter. The power supply voltage of the electric motor 12 may be formed by controlling the solid-state switches of the load bridge 22 using, for example, pulse width modulation (PWM) technology via a control unit 14A of the load bridge 22. The frequency converter may include a current determination component 14C and / or a voltage determination component, such as a current or voltage sensor, which may be arranged to be connected to a power supply cable to the stator windings of the motor 12 to measure stator current and / or voltage.

[0064] As mentioned above Figures 1A to 1C The electric converter unit 14 can be configured to control the operation of the electric motor 12, for example, by field-oriented control or vector control methods known to those skilled in the art.

[0065] In various embodiments of the present invention, Figures 1A to 1C The converter unit 14 shown in any of the figures and described in conjunction with the figures, or specifically its control unit 14A, can be configured to perform Figure 4 As shown and / or in combination Figure 4 At least one embodiment of the described method is used to determine the rotor position of engine 12.

[0066] Therefore, in various embodiments, the control unit 14A may include at least: a processing unit such as a processor or microcontroller, for example for performing calculations and / or running computer program code; and a memory for storing the code, measurement data, etc.

[0067] In some embodiments, the rotor of the electric motor 12 may be arranged such that a force against rotor movement is applied by mechanical or electromechanical braking, maintaining its position, for example, being locked in its position, at least during a portion of the process for determining the rotor position of the motor 12.

[0068] In various embodiments, the electric motor 12 may be one of the following: a synchronous reluctance motor, a permanent magnet motor, a permanent magnet linear motor, a permanent magnet assisted synchronous reluctance motor, or a linear switched reluctance motor.

[0069] Figure 2 An elevator 100 according to an embodiment of the present invention is schematically illustrated. The elevator 100 may include an elevator car 10 coupled to a counterweight 17 via a rope 19, belt, or the like. The rope 19 or the like may travel about a drive pulley 18, in which an electric motor 12 is configured to generate a force on the drive pulley 18 to move the elevator car 10 in response to operation of the electric motor 12. Specifically, the elevator car 10 may be arranged to move in response to the movement (such as rotation) of the rotor 11 of the motor 12.

[0070] At least one elevator brake 16, i.e., one, two, or more elevator brakes 16, can be arranged such that, when controlled by a power outage, the brake 16 is configured to engage with the drive pulley 18, thereby braking the movement of the motor 12, particularly its rotor 11, and thus braking the movement of the elevator car 10 or keeping the elevator car 10 stationary in the shaft. When the brake 16 is energized, the brake 16 opens, thereby allowing the movement of the elevator car 10. Alternatively, the elevator 100 can be implemented without the counterweight 17. Alternatively, the motor 12 can be in the form of a linear motor, having a stator extending along the elevator shaft and a rotor or "moving element" coupled to the elevator car 10, such as... Figure 3 As shown.

[0071] Elevator 100 may include an elevator control unit 1000 for controlling the operation of elevator 100. The elevator control unit 1000 may be a separate device or may be included in other components of elevator 100, such as in or as part of the electric drive 14. The elevator control unit 1000 may also be implemented in a distributed manner, such that, for example, a portion of the elevator control unit 1000 may be included in the electric drive 14, for example, in its control unit 14A, while another portion is in the elevator car 10. The elevator control unit 1000 may also be distributed in more than two locations or in more than two devices.

[0072] The elevator control unit 1000 and / or control unit 14A may include one or more processors, one or more volatile or non-volatile memories for storing computer program code and any data values, and possibly one or more user interface units. The aforementioned components may be communicatively coupled to each other, for example, via an internal bus.

[0073] The processors of elevator control unit 1000 and / or control unit 14A can be configured to at least implement, as described below, such as in Figure 4 China and its combination Figure 4 At least some of the method steps described herein. This method can be implemented by arranging a processor to run at least some portions of computer program code stored in memory, causing the processor, and thus the elevator control unit 1000 and / or control unit 14A, to perform one or more of the method steps described below. Therefore, the processor can be arranged to access memory and retrieve and store any information in memory. For clarity, the term "processor" herein refers to any unit suitable for processing information and controlling the operation of the elevator control unit 1000 and / or control unit 14A, among other tasks. Operation can also be implemented using a microcontroller solution with embedded software. Similarly, the memory is not limited to a certain type of memory, but any type of memory suitable for storing the described multiple pieces of information can be applied in the context of this invention.

[0074] Figure 3 An elevator 100 according to an embodiment of the present invention is schematically illustrated. The elevator 100 may include at least one or more elevator cars 10 moving within an elevator shaft 13 or an elevator car passage 13. The elevator cars 10(one or more) may include an electrical converter unit 14, such as a frequency converter or inverter including a converter device 14D, and / or a second energy storage device such as one or more batteries. The electrical converter unit 14 may be used to operate a mover 11 arranged on the elevator car 10 to move the car 10 along the elevator shaft 13. Other electrically operated devices, such as lighting fixtures, doors, user interfaces, emergency rescue devices, etc., may also be present in the elevator car 10. One or more of these other devices of the elevator car 10 may be operated using the electrical converter unit 14 or another converter, such as an inverter or rectifier. Preferably, the second energy storage device may be electrically coupled to the electrical converter unit 14, for example, electrically coupled to its intermediate circuit 23, to provide power to the electrical converter unit 14 and / or to store electrical energy provided by the electrical converter unit 14 or another converter or other power source. Preferably, elevator 100 may include, for example, a combination Figure 2 The elevator control unit 1000 and / or control unit 14A or similar combination described herein Figure 2 A control unit as described.

[0075] One or more movers 11 may exist coupled to one or each of the elevator cars 10. The number of movers 11 may vary depending on the structure of the electric motor 12, such as the number of stator beams 12A.

[0076] Preferably, the elevator 100 may include at least two landing floors having landing floor doors 25 or openings 25. Doors may also be included in the elevator car 10. Although in Figure 3 The diagram shows two sets or two "columns" of horizontally separated, vertically aligned stopping floors, but it may also have only one column, or more than two columns, such as three columns, as in a traditional elevator.

[0077] Regarding the elevator shaft 13, it may, for example, define a substantially enclosed volume in which the elevator car 10 is adjusted and configured to move. The walls may be, for example, concrete, metal, or at least partially glass, or any combination thereof. The elevator shaft 13 herein essentially refers to any structure or passage along which the elevator car 10 is configured to move.

[0078] As in Figure 3 As can be seen in the diagram, regarding the multi-car elevator 100, depending on the direction of the stator beam 12A, one or more elevator cars 10 can move vertically and / or horizontally along the elevator shaft 13. This is similar to... Figure 3 In one embodiment, one or more elevator cars 10 may be configured along several vertical and / or horizontal stator beams (e.g., such as...). Figure 3 The stator beam 12A is part of the electrical motor of the elevator 100, which moves one or more elevator cars 10 within the elevator shaft 13. Preferably, the stator beam 12A can be arranged in a fixed manner, that is, it is stationary relative to the elevator shaft 13, for example, by means of a fastener relative to the wall of the shaft, which can be arranged to be rotatable to change the position of the elevator car 10.

[0079] Figure 4 A flowchart of a method according to an embodiment of the present invention is shown.

[0080] Typically, the method comprises at least two main sections. Furthermore, preferably, the rotor 11 of the engine 12 can be arranged to maintain its position by applying a force against movement of the rotor 11 from its position, for example, at least during the first main section and optionally also during the second main section.

[0081] In the first main section, at least a first excitation signal, such as current or voltage, is supplied to the electric motor 12, and in response to the first excitation signal, a first response signal, such as voltage or current, is generated in the motor. Based on the first response signal, the positions of the direct axis and the orthogonal axis can be determined. Figure 5A An example is shown schematically at a medium height. Figure 5A The first response current RS1 is shown as a function of electrical angle, such as one or two complete cycles from zero to 360 degrees or from zero to 720 degrees. Figure 5A The horizontal axis in the diagram does not necessarily correspond to zero amplitude, but rather to a finite positive value. In some embodiments, the horizontal axis may refer to zero amplitude.

[0082] However, in some embodiments, because the amplitude (e.g., its vector quantity) of the first excitation signal can be arranged to be low, the force generated by the first excitation signal for moving the rotor 11 is less than the force resisting the movement of the rotor 11. Therefore, the low amplitude of the excitation signal may prevent the positions of the north and south poles in the rotor 11 from being determined in the first main portion. On the other hand, only a small amount of force is needed to hold the rotor 11 in its position. For example, only a brake, such as an elevator brake 16, can be provided for this purpose.

[0083] In the second main section, at least a second excitation signal is supplied to the motor 12. Preferably, the second excitation signal is formed based on the determined position of the direct axis D of the electric motor 12. Therefore, since the characteristics of the second excitation signal correspond to the position of the direct axis D, ideally, even if the amplitude of the second excitation signal is significantly higher than that of the first excitation signal, no force for moving the rotor 11 will be generated due to the second excitation signal. In practice, due to the structure of the motor 12, for example, a small amount of force for moving the rotor 11 can be generated by the second excitation signal. Subsequently, a second response current generated in response to the second excitation signal can be determined. Since the amplitude of the second excitation signal is large, or at least higher than that of the first excitation signal, it can now be arranged in the second main section to determine the force in the rotor 11... Figure 5B The location of the North Pole related to +D and its relation to Figure 5B The location of Antarctica related to -D in the equation.

[0084] exist Figure 5B The example is illustrated schematically at a medium height. Figure 5B The second response current RS2 as a function of electrical angle is shown. It can be seen that a higher amplitude indicates the North Pole, while a lower amplitude indicates the South Pole. It should be noted that, preferably, Figure 5A and Figure 5B The electrical angle in the equation corresponds to the following meanings: Figure 5A The same straight axis is located in Figure 5BAt the corresponding electrical angle in the equation. Figure 5B The horizontal axis in the diagram does not necessarily correspond to zero amplitude, but rather to a finite positive value. In some embodiments, the horizontal axis may refer to zero amplitude.

[0085] As in Figure 5B As can be seen in Figure 5, determining the rotor position 46 may include comparing the maximum value of the second response current RS2 to determine the positions of the south and north poles of rotor 11. It is evident in Figure 5 that the maximum value at the north pole (N) can be greater than the maximum value at the south pole (S). At the north pole (N), the core of engine 12 is magnetized, and therefore, the current amplitude increases. At the south pole (S), the core of engine 12 is demagnetized, and therefore, the current amplitude decreases.

[0086] Therefore, as a result of the first and second main components, the position of rotor 11 can be determined without requiring a large amount of force to hold rotor 11 in its position. Furthermore, the noise and vibration caused by the excitation signal can be lower than in known solutions.

[0087] Item 40 may refer to the startup phase, during which necessary tasks such as those for components and systems are acquired, and calibration and other configurations can be performed.

[0088] Item 41 may refer to supplying a first excitation signal, such as a first AC voltage or current signal, to the electric motor 12.

[0089] Preferably, the first excitation signal can be configured to rotate about at least one pole pair of the engine 12.

[0090] According to various embodiments, the amplitude of a first excitation signal, such as a first AC voltage signal, can be such that it generates one or more currents in the engine 12 that magnetically saturate at least a portion of the core material of the rotor 11.

[0091] In addition, the first excitation signal may include an AC voltage signal that generates a rotating field in one direction and another AC voltage signal that generates a rotating field in the opposite direction, which are continuously supplied inside the electric motor 12.

[0092] Additionally, the method may include: before the supply of the first excitation signal 41, at least during the supply of the first excitation signal and the determination of the first response signal RS1, applying a force of a first amount to hold the rotor 11 of the engine 12 in its position, wherein the first amount is related to the direction of resistance to movement of the rotor 11, so that even if the first excitation signal generates some force that would otherwise cause the rotor 11 to move, the first amount can still hold the rotor 11 in its position. Therefore, the force generated by the first excitation signal to move the rotor 11 can be less than the first amount, such that the rotor 11 remains in its position at least during the supply of the first excitation signal 41. The first amount may, for example, correspond to the braking force of a brake 16, such as the braking force of one of at least one elevator brake 16.

[0093] Item 42 may refer to determining a first response signal RS1, such as current or voltage, generated in the electric motor 12 in response to the first excitation signal. Preferably, determining the electrical angle may include determining the electrical angle of the first excitation signal when the maximum amount of the first response signal RS1, such as current, occurs.

[0094] In some embodiments, the amplitude of the first excitation signal is such that it causes a lower force for moving the rotor 11 than a first quantity, such as a first quantity of braking force to counteract the movement of the rotor 11.

[0095] Item 43 may refer to determining the electrical angle of the direct axis D of the electric motor 12 relative to a stationary reference frame based on the first response signal RS1, for example, the electrical angle with respect to the stator of the electric motor 12.

[0096] Item 44 may be directed to supply a second excitation signal to the electric motor 12, wherein the second excitation signal is based on the determined electrical angle.

[0097] In various embodiments, the amplitude of the second excitation signal may be at least twice the amplitude of the first excitation signal, preferably at least three times, or even more preferably at least four times.

[0098] In various embodiments, the second excitation signal can be configured to be supplied by gradually increasing its amplitude in order to avoid a stepwise change in the force generated in the engine 13. The gradual increase in the excitation signal minimizes noise caused by engine bearing clearance (i.e., because the second excitation signal causes the rotor 11 to move due to the clearance).

[0099] Item 45 may refer to determining a second response signal RS2, such as current or voltage, generated in the electric motor 12 in response to the second excitation signal.

[0100] Item 46 may refer to determining the rotor position based on a second response signal RS2, such as current or voltage. In various embodiments, determining the rotor position may include comparing the maximum value of the second response signal RS2 to determine the positions of the south pole S and north pole N of the rotor 11.

[0101] At item 49, terminate or stop the method execution. The method can be executed once, continuously, intermittently, on demand, or periodically.

[0102] In various embodiments, the electric motor 12 may be an elevator motor 12 of an elevator 100, wherein the elevator 100 includes at least one elevator brake 16 for braking the motor 12, and the method includes applying force, for example, by at least one elevator brake 16.

[0103] It should be remembered that, for example, regarding Figure 6A and Figure 6B During the determination of the position of the rotor 11 as described above, movement of the rotor 11 or mover 11 of the electric motor 12 can be stopped, for example by means of a brake 16 (such as at least one elevator brake 16).

[0104] Figure 6A An electric converter unit 14 according to an embodiment of the present invention is schematically illustrated. The electric converter unit 14 can be electrically connected to an electric motor 12, such as a synchronous reluctance motor, a permanent magnet motor, a permanent magnet linear motor, a permanent magnet assisted synchronous reluctance motor, or a linear switched reluctance motor. An engine winding 51, such as that included in the rotor 11, stator, or in the case of a linear motor, as an inductor has been schematically shown. Although the inductor is shown as having a delta configuration, alternatively, the winding may also be in a Y-shaped or star configuration, for example. The converter unit 14 may include a converter device 14D, such as a frequency converter or inverter, containing solid-state semiconductor switches. The switches may be, for example, insulated-gate bipolar transistors or silicon carbide junction field-effect transistors. Examples of the converter unit 14 are described above regarding... Figures 1A to 1C It has been described.

[0105] Figure 6A An example of a first excitation signal ES1 for a winding or passing through a winding is shown, i.e., for example, a first excitation signal ES1 between two phases of engine 12. However, it should be noted that in the case of voltage, it can be between a phase and ground potential. In this example, the first excitation signal ES1 is an AC voltage signal; however, in some other embodiments, it can be an AC current signal.

[0106] Preferably, the converter unit 14 can be configured to generate a first excitation signal ES1. For example... Figure 6AIn the example shown, the first excitation signal ES1 is an AC voltage signal generated by the PWM in converter unit 14. However, similar signals with a phase difference from the signal in question can also be generated through two other inductors. Converter unit 14 can be controlled by control unit 14A, in which one or more reference excitation signals ES_REF can be generated. Figure 6A In this process, one or more reference excitation signals ES_REF are formed to generate a first excitation signal ES1; however, a second excitation signal ES2 can be generated in a similar manner. The one or more reference excitation signals ES_REF may include a full three-phase reference signal, such as in... Figure 6A As shown, or it could be a vector such as a voltage vector, which is available in the vector control method operating in the converter unit 14 and is specifically related to the control of its controllable switches.

[0107] Therefore, in various embodiments, the magnitude of the reference voltage or current vector can be configured to be constant, however, the vector is configured to rotate.

[0108] Furthermore, by supplying a first excitation signal ES1 to the engine 12, a first response signal RS1 is generated in the engine 12, which can be determined by the current determining component 14C or the voltage determining component. In some other embodiments, the first response current RS1 can be a voltage signal. Figure 6A The first response current RS1 is the current of one phase of the motor 12. Because the electric motor 12 is typically an inductive load, the first excitation signal ES1 and the corresponding first response current RS1 are phase-shifted.

[0109] Figure 6B An electrical converter unit 14 according to an embodiment of the present invention is schematically shown. Unit 14 may include a conversion unit, preferably within a control unit 14A, for forming a three-phase power supply voltage reference ES_REF, such as voltages comprising the R-phase, S-phase, and T-phase, for example, based on an amplitude reference U and an electrical angle reference θ. In this case, the three-phase power supply voltage reference is formed as a function of the electrical angle reference θ. For example, in this case, the power supply voltage reference for the R-phase may be of the form: amplitude * sin(θ), where the amplitude may be equal to U.

[0110] In an embodiment, the load bridge 22 of the converter unit 14 (see...) Figure 1CThe control block 61 controls the solid-state switch of the load bridge 22, for example, based on the aforementioned three-phase power supply voltage reference ES_REF, to generate a first excitation signal ES1 for supply to the electric motor 12. In this embodiment, the value of the electrical angle reference θ can be arranged to vary linearly, in which case the rotational or (in a linear motor) speed of the power supply voltage reference ES_REF and the first excitation signal ES1 is arranged to be constant.

[0111] In response to the first excitation signal ES1 generated in one or more windings of the electric motor 12, the three-phase current in some embodiments may be arranged as a function of the electric angle reference θ of the electric motor 12, for example, by measurement.

[0112] The instantaneous value of the determined three-phase current (i.e., the first response signal RS1) can be determined at the determining unit 62 using methods known in the prior art, such as the instantaneous value related to the amplitude.

[0113] Furthermore, as is known in the prior art, a current or voltage vector representing the three-phase current or voltage of the first response current RS1 can be determined based on the phase current or voltage.

[0114] According to some embodiments, changes in the inductance in the magnetic circuit of the electric motor 12 can cause the amplitude of the determined first response current RS1, such as the amplitude of the current vector, to vary as a function of the electrical angle reference θ. This can be seen in the amplitude of the current vector of the first response current RS1 determined based on the three-phase current. Figure 5A An example is illustrated schematically at a medium height. In the ideal case of constant impedance, a sinusoidal excitation voltage will induce a sinusoidal response current, the magnitude of which will be constant. However, in reality, this is never the case.

[0115] exist Figure 5AIn this context, the change in the amplitude of the electric angle reference θ is caused by the change in the inductance of the motor's magnetic circuit due to factors such as local saturation of the motor's magnetic circuit. Here, local saturation refers to a type of magnetic circuit saturation phenomenon that changes relative to the electric motor's electric angle. This local saturation is caused by factors such as the permanent magnets in the rotor. In this case, due to local saturation, the position of the permanent magnets in the rotor 11 can be determined, and thus the positions of the direct axis D and the orthogonal axis Q of the motor 12 can be determined. On the other hand, changes in the geometry of the magnetic circuit, such as changes in the length of the air gap in the electric motor 12, can also lead to local changes in the inductance of the electric motor 12's magnetic circuit. This change in the length of the air gap occurs, for example, in a salient-pole electric motor 12. The local change in the inductance of the electric motor 12's magnetic circuit caused by the aforementioned type of change in the geometry of the electric motor 12's magnetic circuit can also be used to determine the position of the rotor 11. In this case, the impact angle of the rotor 11, i.e., the position of the magnetic poles N and S of the rotor 11, can also be determined when the rotor 11 is locked in its position.

[0116] Therefore, in various embodiments, the amplitude of the first excitation signal ES1 is arranged such that it causes at least local saturation of the magnetic circuit of the engine 12, thereby causing a change in the amplitude of the response signal as a function of the electrical angle reference θ.

[0117] The first excitation signal ES1 can be formed by changing the electrical angle reference θ from zero to 2π, i.e., changing it by a full cycle. Therefore, the phase voltages can be UR = U*sin(θ), US = U*sin(θ + 2*π / 3), and UT = U*sin(θ - 2*π / 3). Thus, the voltage vector reference has a constant amplitude; however, it results in a rotating magnetic field in engine 12. Under ideal conditions, the currents would, for example, sum to zero. However, due to magnetic saturation, the sum of the currents exhibits a sinusoidal variation in its amplitude. The amplitude reveals which electrical angles are poles.

[0118] The impedance of the magnetic circuit can also cause a phase difference between the supplied first excitation signal ES1 and the determined first response signal RS1, such as a current. To compensate for the phase difference, in some embodiments, as described above, the measurements described above can be repeated by continuously supplying one AC voltage signal as a function of an electrical angle reference θ and another AC voltage signal as a function of an electrical angle reference θ. Therefore, the first excitation signal ES1 can actually include two or more consecutively supplied signals. The rotation direction of the other AC voltage signal can be chosen to be opposite to the rotation direction of the one AC voltage signal of the first excitation signal ES1, in which case the phase difference between the one AC voltage signal and the corresponding first response current RS1 can be in the opposite direction compared to the phase difference between the other AC voltage signal of the first excitation signal ES1 and its corresponding current response RS1. In view of the above, it is clear that the first response current RS1 can also actually include two or more consecutively generated signals.

[0119] The specific examples provided in the above description should not be construed as limiting the applicability and / or interpretation of the appended claims. Unless otherwise expressly stated, the list and groups of examples provided in the above description are not exhaustive.

Claims

1. A method for determining the rotor position of an electric motor (12), the method comprising: - Apply a force of a first amount to hold the rotor (11) of the engine (12) in its position. - A first excitation signal (ES1) is supplied (41) to the electric motor (12). - Determine (42) the first response signal (RS1) generated in the electric motor (12) in response to the first excitation signal (ES1), -Based on the first response signal (RS1), determine the electrical angle of the direct axis (D, -D, +D) of the electric motor (12) relative to the stationary reference frame. - A second excitation signal (ES2) is supplied (44) to the electric motor (12), wherein the second excitation signal (ES2) is based on the determined electrical angle. - Determine (45) the second response signal (RS2) generated in the electric motor (12) in response to the second excitation signal (ES2), and - Determine the rotor position (46) based on the second response signal (RS2). The force is applied at least during the supply (41) first excitation signal (ES1) and the determination (42) first response signal (RS1), and the first amount is related to the direction of the movement of the rotor (11).

2. The method according to claim 1, wherein The first excitation signal (ES1) is a first AC voltage signal with a constant amplitude, and the first response signal (RS1) is a first response current generated in response to the first AC voltage signal, or / and The second excitation signal (ES2) is a second AC voltage signal with a constant amplitude, and the second response signal (RS2) is a second response current generated in response to the second AC voltage signal.

3. The method according to claim 1, wherein, The first excitation signal (ES1) is a first alternating current signal with a constant amplitude, and the first response signal (RS1) is a first response voltage generated in response to the first alternating current signal, or / and The second excitation signal (ES2) is a second alternating current signal with a constant amplitude, and the second response signal (RS2) is a second response voltage generated in response to the second alternating current signal.

4. The method according to claim 1, wherein, Determining the rotor position (46) involves comparing the maximum value of the second response signal (RS2) to determine the positions of the south and north poles of the rotor (11).

5. The method according to claim 1, wherein, The first excitation signal (ES1) includes an AC excitation signal that generates a rotating field in one direction and another AC excitation signal that generates a rotating field in the opposite direction, which are continuously supplied inside the engine (12).

6. The method according to claim 1, wherein, The determination of the electrical angle (43) includes determining the electrical angle of the first excitation signal (ES1) when the maximum amount of the first response signal (RS1) occurs.

7. The method according to claim 1, wherein, The second excitation signal (ES2) is configured to be supplied by gradually increasing its amplitude in order to avoid stepwise changes in the force generated in the engine (12).

8. The method according to any one of claims 4 to 7, wherein, The electric motor (12) is an elevator motor (12) of an elevator (100), wherein the elevator (100) includes at least one elevator brake (16) for braking the motor (12), and the method includes applying force through the at least one elevator brake (16).

9. The method according to any one of claims 4 to 7, wherein, The force generated by the first excitation signal (ES1) to move the rotor (11) is less than the first amount, so that the rotor maintains its position during the supply (41) of the first excitation signal (ES1).

10. The method according to any one of claims 4 to 7, wherein, The electric motor (12) is one of the following: a synchronous reluctance motor, a permanent magnet motor, and a linear switched reluctance motor, wherein the synchronous reluctance motor is a permanent magnet assisted synchronous reluctance motor, and the permanent magnet motor is a permanent magnet linear motor.

11. An elevator (100), comprising: Elevator car (10), An elevator motor (12) is configured to move the elevator car (10). An electric converter unit (14) is used to operate the elevator motor (12). At least one elevator brake (16), and The control unit (1000; 14A) is configured to at least cause the electrical converter unit (14) to: - Apply a force of a first amount to hold the rotor (11) of the engine (12) in its position. - A first excitation signal (ES1) is supplied (41) to the elevator motor (12). - Determine (42) the first response signal (RS1) generated in the elevator motor (12) in response to the first excitation signal (ES1); -Based on the first response signal (RS1), determine the electrical angle of the direct axis (D, -D, +D) of the electric motor (12) relative to the stationary reference frame. - A second excitation signal (ES2) is supplied (44) to the electric motor (12), wherein the second excitation signal (ES2) is based on the determined electrical angle. - Determine (45) the second response signal (RS2) generated in the electric motor (12) in response to the second excitation signal (ES2), and -The rotor position (46) is determined based on the second response signal (RS2). The force is applied at least during the supply (41) first excitation signal (ES1) and the determination (42) first response signal (RS1), and the first amount is related to the direction of the movement of the rotor (11).

12. The elevator (100) according to claim 11, wherein, Determining the rotor position (46) involves comparing the maximum value of the second response signal (RS2) to determine the positions of the south and north poles of the rotor (11).

13. The elevator (100) according to claim 11 or 12, wherein, The determination of the electrical angle (43) includes determining the electrical angle of the first excitation signal (ES1) when the maximum amount of the first response signal (RS1) occurs.

14. An electrical converter unit (14) configured to: - Apply a force of a first amount to hold the rotor (11) of the engine (12) in its position. - Supply (41) the first excitation signal (ES1) to the elevator motor (12), - Determine (42) the first response signal (RS1) generated in the elevator motor (12) in response to the first excitation signal (ES1); -Based on the first response signal (RS1), determine the electrical angle of the direct axis (D, -D, +D) of the electric motor (12) relative to the stationary reference frame. - A second excitation signal (ES2) is supplied (44) to the electric motor (12), wherein the second excitation signal (ES2) is based on the determined electrical angle. - Determine (45) the second response signal (RS2) generated in the electric motor (12) in response to the second excitation signal (ES2), and -The rotor position (46) is determined based on the second response signal (RS2). The force is applied at least during the supply (41) first excitation signal (ES1) and the determination (42) first response signal (RS1), and the first amount is related to the direction of the movement of the rotor (11).

15. The electric converter unit (14) according to claim 14, comprising a converter device (14D) and a current determination component (14C) and / or a voltage determination component for determining at least the first response signal and the second response signal (RS1, RS2).

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