Control device for an electric motor and braking device

Abstract

A control device for an electric motor comprising a control board that controls the drive of an electric motor and temperature sensing sections arranged on the control board at least two positions that differ in their tendency to change temperature.

Description

TECHNICAL AREA

[0001] The invention relates to a device for controlling an electric motor and a braking device with an electric motor. STATE OF THE ART

[0002] For example, patent literature 1 discloses a control device for an electric power steering system which estimates the motor winding temperature from the terminal-to-terminal voltage in a motor and a motor current detection value and then protects the motor temperature based on the motor winding temperature. CITATION LIST PATENT LITERATURE

[0003] PTL 1: Unexamined publication of Japanese patent application (Kokai) No. 10-100913 SUMMARY OF THE INVENTIONAL PROBLEM

[0004] According to the temperature estimation method disclosed in patent literature 1, it is necessary to measure the terminal-to-terminal resistance in the motor at the reference temperature with respect to each product and to store the measured values ​​in a non-volatile memory section. Such a method leads to an increase in the number of steps in the manufacturing process and thus to an increase in manufacturing costs. SOLUTION TO THE PROBLEM

[0005] The invention relates to the provision of a device for controlling an electric motor, which is able to estimate the temperature of an electric motor while limiting an increase in manufacturing costs, as well as a braking device.

[0006] One embodiment of the invention provides for temperature sensing sections that are arranged at at least two locations on a control board that controls the drive of an electric motor, which differ in their tendency to change temperature.

[0007] One embodiment of the invention makes it possible to estimate the temperature of the electric motor while simultaneously limiting an increase in manufacturing costs. List of characters Fig. Figure 1 is a block diagram showing an essential part of a braking device according to a first embodiment of the invention. Fig. Figure 2 shows an essential part of a motor control device and an electric motor in the braking system of Fig. 1. Fig. Figure 3 is a diagram showing the changes in temperature over time as measured by the first and second temperature sensing sections in the braking system of Fig. 1. This can be obtained with the ambient temperature and the engine temperature. Fig. Figure 4 is a block diagram showing a main part of a braking device according to a second embodiment of the invention. DESCRIPTION OF THE EXECUTION FORMS

[0008] Embodiments of the invention are discussed with reference to the accompanying illustrations.

[0009] Fig. Figure 1 is a block diagram showing an essential part of an electric braking device 1 according to a first embodiment of the invention. Fig. Figure 2 is a block diagram showing an essential part of a motor control device. 20 in the electric braking device 1 in Fig. Figure 1 shows. The electric braking device 1 is a braking device that exerts a braking force on each wheel by rotating a disc. D compresses, which rotates with each wheel (not shown) of a vehicle. As in Fig. As shown in 1, the electric braking device 1 comprises a braking mechanism. 10 with respect to each wheel that is braked by each corresponding electric braking device 1. The braking mechanism 10 includes the brake pads 2 and 3 , which against the window D be pressed, and a piston 4 , who the brake pads 2 and 3 moved. The braking mechanism 10 It also includes an electric motor. 11 and a mechanism 12 for converting a rotation-linear motion, which converts the rotation of the electric motor 11 converts into a linear motion and transfers the linear motion to the piston 4 transfers.

[0010] Since the electric braking device 1 controls the braking mechanism 10 With regard to each wheel, which, as mentioned, is braked by the electric braking device 1, there are typically several braking mechanisms.10 provided (e.g. four braking mechanisms) 10 (if the vehicle is a four-wheeled vehicle). For the sake of clarity in the illustrations and description, the electric braking device 1 is mainly referred to here in relation to one of the braking mechanisms. 10 and its components are discussed. The part relating to a braking mechanism 10 The aspects discussed are applicable to all other braking mechanisms, unless explicitly stated otherwise.

[0011] The electric braking device 1 further comprises a motor control device. 20 , which control the operation of the electric motor 11 controls. In Fig. 1 is the electric motor 11 , the mechanism 12 for converting the rotational-linear motion and the control device 20 Outside of a brake caliper 5, the components are shown as separate blocks from the brake caliper 5. The figure shows the electric motor. 11, the mechanism 12 for converting the rotational-linear motion and the control device 20 merely as functional blocks in a schematic manner and is not intended to represent the spatial arrangement of the components. 11 , 12 and 20 to be limited. In general, the electric motor is used in the electric braking device 1. 11 and the mechanism 12 for converting the rotational-linear motion together with the piston 4 located in the brake caliper 5. Alternatively, the control device 20 also located in brake caliper 5.

[0012] The braking mechanism 10 According to the first embodiment, a freely chosen component can be included (e.g., a delay mechanism that slows the rotation of the electric motor). 11 delayed), which is suitable as a braking device, by compressing the disc rotating with the wheel D exerts a braking force on each wheel.

[0013] As in Fig. The motor control device shown in section 2 includes 20 a motor drive section 21 and a controller 26, which are mounted on a control board 20a are attached to the engine control device 20 is assigned (in Fig. 2 show solid lines, which represent the motor control device 20 display, and also the control board 20a on, which is in the engine control device 20 (included). In the electric braking device 1, the electric motor includes 11 For example, a three-phase synchronous motor. Accordingly, the motor drive section 21 comprises a three-phase inverter device that converts direct current, supplied to the motor drive section 21 by a power source 37, into three-phase alternating current and supplies the three-phase alternating current to the electric motor. 11The controller 26 outputs a switch control signal 31 to the motor drive section 21 for controlling the ON / OFF switching of a semiconductor switching element (e.g., with a MOSFET) 22, which forms the three-phase inverter device. The motor drive section 21 controls the drive of the electric motor. 11 by pulse width modulation (PWM) in accordance with the switch control signal 31.

[0014] The electric motor is located in the electric braking device 1. 11 a rotary position detection section 38 is provided. A rotary position signal 36, which corresponds to a rotary position of the electric motor, is generated. 11 The corresponding value is transmitted from the rotary position detection section 38 to the controller 26 of the motor control device. 20A current signal 32, corresponding to the motor drive current (winding current) of each phase, is also input from the motor drive section 21 into the controller 26. The controller 26 is configured to be able to vector-controlled the rotational speed of the electric motor. 11 to implement in accordance with the above information.

[0015] A first temperature measurement section 23 and a second temperature detection section 24 , which include thermostats, for example, are located on the control board. 20a the engine control device 20 The temperature signals 33 and 34 are input into the controller 26. Temperature signals 33 and 34 correspond to temperatures measured by the first and second temperature sensing sections. 23 and 24 to be measured. The first temperature measurement section 23 is located in a heat-generating section on the control board20a the engine control device 20 arranged. The second temperature detection section 24 is located in a non-heat-generating section on the control board 20a the engine control device 20 located in a position away from the heat-generating section.

[0016] The heat-generating section is a specific or local area on the control board. 20a The heat-generating section encompasses a position where a component is mounted that generates heat during operation. This component is typically one that produces a relatively large amount of heat. The non-heat-generating section is a specific or localized area on the control board. 20a , on which no component that generates heat during operation is attached. If a component is attached to the non-heat-generating section, the amount of heat generated by the component is relatively small.

[0017] One of the typical heat-generating sections in the engine control device 20 The motor drive section 21, or more precisely, a specific or local area that includes the semiconductor switching element 22 as a heat-generating component, is located in a motor drive section 21, or more precisely, a specific or local area that includes the semiconductor switching element 22 as a heat-generating component. In a Fig. The first temperature measurement section is shown in example 2. 23 arranged in the immediate vicinity of the semiconductor switching element 22. In this sense, it shows Fig. 2 an example where the first temperature detection section 23 is located in the heat-generating section. The heat-generating section of the motor control device 20 However, this is not related to the in Fig. 2 shown, limited. For example, the area including the controller 26 can be considered a heat-generating section. If, in addition, there is a drive unit (not shown) for the inverter device on the control board 20aSince the area is attached, including the drive mechanism, it can also be considered a heat-generating section. According to the invention, the location where the first temperature sensing section is attached is 23 is arranged, taking into account the conditions of component mounting on the control board 20a and the like properly determined. The first temperature detection section 23 It can be located near the heat-generating sections mentioned above.

[0018] In the Fig. The second temperature measurement section is shown in example 2. 24 in a peripheral area of ​​the control board 20a the engine control device 20 arranged. In this example, it is assumed that the specific or local area where the second temperature sensing section is located is... 24The area in question is a non-heat-generating section, meaning that no component that generates heat during operation, or preferably no component at all, is located in that specific area. Furthermore, the specific area in which the second temperature sensing section is located is... 24 is arranged away from all heat-generating sections, including the motor drive section 21, the controller 26 and the like, and preferably furthest away from all heat-generating sections.

[0019] The control board 20a the engine control device 20 This is generally due to the actuation of the engine control device. 20 The temperature increased. The resulting temperature is not uniform across the control board. 20a The temperature distribution during the operation of the motor control device 20is locally uneven, depending on the heat-generating properties of the components on the control board. 20a at their respective positions, or by other factors. With such a temperature distribution, the heat-generating sections and areas near the heat-generating sections are areas that indicate a relatively high temperature, and the non-heat-generating sections and areas located away from the heat-generating sections are areas that indicate a relatively low temperature.

[0020] The controller 26 can be connected to a vehicle data bus (not shown) to send and receive a variety of information, including information necessary for engine drive control and temperature estimation (discussed later), to each other and to another electronic control unit (ECU) via the vehicle data bus.

[0021] The controller 26 is preferably configured as a generally known microcomputer system equipped with a CPU (central processing unit), a ROM (read-only memory), a RAM (random access memory), an I / O (input / output) interface, and the like. Alternatively, the controller 26 may consist partially or entirely of freely chosen, suitable hardware or software, or a combination of hardware and software, as long as the controller 26 is capable of implementing the motor drive control and temperature estimation, which will be discussed in detail later.

[0022] In the electrical braking device 1 thereby established, the rotation of the electric motor is stopped. 11 , which is driven by the motor drive section 21 under the control of the controller 26, by the mechanism 12 for converting the rotational-linear motion of the braking mechanism 10converted into a linear motion. The linear motion transfers thrust to the piston. 4 and causes the piston to 4 moving brake pads 2 and 3 on the disc D press and thereby generate a braking force.

[0023] The following discussion will focus on estimating the temperature of the electric motor. 11 (i.e., the winding temperature of the electric motor) 11 ) in the electric braking device 1 with reference to Fig. 3 in addition to the Fig. 1 and Fig. 2 explained. The controller 26 of the motor control device 20 is either set up, having previously determined a temperature coefficient α of the winding material of the electric motor. 11 and a torque constant of the electric motor 11 to store, or it is able to, if necessary, store the temperature coefficient α of the winding material of the electric motor. 11and the torque constant of the electric motor 11 to be obtained from another electronic control device installed in the vehicle.

[0024] Fig. Figure 3 is a diagram showing a change in temperature over time (41) from the first temperature recording section. 23 is obtained, and the temperature 42, which comes from the second temperature detection section 24 is obtained, assuming an ambient temperature 43 and winding temperature 40 of the electric motor 11 shows.

[0025] In the electric braking device 1, the initial resistance Ri of the winding of the electric motor is 11 First determined as described below. One in Fig. The interval A shown in Figure 3 is a state in which the engine control device 20 is in operation. During interval A, the temperatures 41 and 42 of the control board are 20a the engine control device20 generally higher than the ambient temperature 43 due to the heat generated by the operation of the components on the control board 20a is caused by attached components. According to a Fig. In the example shown in section 3, it is assumed that the winding temperature of the electric motor is 40°C. 11 is higher than temperatures 41 and 42 of the control board 20a Since the first temperature measurement section 23 in the heat-generating section on the control board 20a and the second temperature detection section 24 in the non-heat-generating section on the control board 20a When arranged, temperature 41 is higher than temperature 42.

[0026] At time P, the vehicle stops, and the ignition is switched off. During an interval B after time P, the operation of the motor drive section 21, and thus the excitation of the electric motor, is discontinued. 11interrupted until an initial resistance is reached, while the excitation of the motor control device 20 itself continues. Since the operation of the motor drive section 21 is interrupted, it is assumed that the temperatures 41 and 42 are approaching the ambient temperature. 43 be lowered and at the same time the winding temperature of the electric motor 11 , whose excitation is interrupted, also in the direction of the ambient temperature 43 is lowered.

[0027] Controller 26 continuously monitors the difference between temperatures 41 and 42 during interval B and determines whether the difference becomes equal to or less than a predefined threshold. The predefined threshold is set to a value such that temperatures 41 and 42 are considered substantially similar (e.g., within a margin of error) when the difference between temperatures 41 and 42 becomes equal to or less than the threshold. If the temperature from the first temperature sensing section 23 obtained temperature 41 and that from the second temperature measurement section 24 The obtained temperature 42 match each other when the first and second temperature detection sections 23 and 24 Since they are arranged at two positions that differ in their tendency to change temperature, this means that temperatures 41 and 42 both correspond to the ambient temperature. 43This leads to the assumption that the winding temperature of the electric motor... 11 after a sufficient period of time before reaching ambient temperature 43 also the ambient temperature 43 reached.

[0028] At this point, the following equation is formulated. Temperatur 41=Temperatur 42=Umgebungstemperatur 43=Wicklungstemperatur 40 des Elektromotors 11

[0029] Referring to the diagram in Fig. 3. The controller 26 determines that the difference between temperature 41 and temperature 42 at a given time within a range C is equal to or less than the specified threshold. The controller 26 then performs the following process to determine the initial resistance. During this operation, the controller 26 controls the motor drive section 21 such that the q-axis current of the electric motor 11is set to zero and only the d-axis (hereinafter also simply referred to as d-axis excitation) is excited by the switch control signal 31 in order to excite the winding current without the electric motor 11 to rotate. The controller 26 calculates the initial resistance Ri of the electric motor winding. 11 according to the following equation (2) based on the input winding current (current signal 32). Ri=Umrichterspannung×BETRIEB / Wicklungsstrom where the converter voltage is the source voltage of the current source 37; OPERATION is an operating condition in the ON / OFF operation of the semiconductor switching element 22 of the motor drive section 21; and the winding current is a current value corresponding to the current signal 32.

[0030] The controller 26 stores the calculated initial resistance Ri and the initial temperature Ti, expressed by equation (1), in a non-volatile memory section. This non-volatile memory section is made available to the control unit 26 or another electronic control device installed in the vehicle. After the initial resistance determination process is complete, the excitation of the motor control device is initiated. 20 interrupted at time Q.

[0031] The winding temperature of the electric motor 11 is estimated at a freely selectable time after the initial resistance conservation process has been carried out, as described below.

[0032] First, the resistance Rc of the winding at the freely chosen time (hereinafter also referred to as current resistance Rc) is calculated according to an equation (3). Rc= ( Umrichter Spannung-Drehmomentkonstante×Drehzahl ) × BETRIEB / Wicklungsstrom where the inverter voltage is the source voltage of the current source 37; the OPERATION is the operating ratio in ON / OFF operation of the semiconductor switching element 22 of the motor drive section 21; the winding current is a current value corresponding to the current signal 32; the torque constant is one for the electric motor 11 specific torque constant, and the rotational speed is the rotational speed of the electric motor. 11 at the point of estimation, which is obtained on the basis of the rotation position signal 36.

[0033] It goes without saying that if the rotational speed is set to zero, equation (3) is applicable to a situation in which the rotation of the electric motor 11 is exposed. If the current resistance Rc is to be maintained while the electric motor is rotating. 11If the vehicle is exposed to a current, for example in a situation where it is stopped, it is preferable that the current value of the winding current is maintained by the electric motor 11 is driven by the excitation of the d-axis, without the electric motor 11 to rotate in a similar manner to when the process of obtaining the initial resistance is performed.

[0034] The controller 26 then receives the estimated current winding temperature Tc of the electric motor. 11 according to the following equation (4) based on the calculated current resistance Rc of the winding, the stored initial resistance Ri of the winding and the stored initial temperature Ti of the winding as well as the stored temperature coefficient α of the winding material. Tc= ( Rc-Ri ) / ( α × Ri ) +Ti

[0035] The following is an example of the estimated current winding temperature Tc under the condition that the winding material is copper (α = 0.393% / °C) and that the initial temperature Ti is 25°C. If the inverter voltage and operating ratio are 12 V and 50% respectively, and the winding current at this time is 30 A, the initial resistance Ri of the winding during operation to maintain the initial resistance is 0.2 Ω according to equation (2). If, at the time of the temperature estimate, the inverter voltage, operating ratio, and a back electromotive force of the electric motor are 11 (i.e., torque constant × rotational speed) 12 V, 100%, and 3 V respectively, and if the winding current at that time is 30 A, the current resistance Rc of the winding is 0.3 Ω according to equation (3). In such a case, the estimated current temperature Tc of the winding is approximately 152°C according to equation (4).

[0036] The process for obtaining the initial resistance can preferably be performed once during an initial phase or more than once, as required, during the vehicle's life cycle. If the process for obtaining the initial resistance is performed more than once, the last initial resistance Ri and the last initial temperature Ti can be used to estimate the current temperature Tc of the winding. Alternatively, it is also possible, for example, to calculate average values ​​from a variety of initial resistances Ri and initial temperatures Ti to obtain appropriate representative values ​​for use.

[0037] Two temperature sensing sections, namely the first and the second temperature sensing section 23 and 24 , are on the control board 20a the engine control unit 20arranged. According to the invention, however, the temperature sensing sections can comprise temperature sensing sections, each corresponding to two or more sections that differ in their tendency to change temperature (e.g., two or more heat-generating sections and / or two or more non-heat-generating sections).

[0038] In conventional braking systems, a screw thermistor is attached to the housing of an electric motor to estimate the motor's winding temperature. The winding temperature is estimated from the housing temperature obtained through the thermistor, a constant obtained during heat generation / dissipation, an integrated value of the winding current, and similar factors. This method presents the problem that the number of components that must be arranged in a confined space, such as a wheel well, is increased. This necessitates providing a physical connection point for temperature measurement in a location such as an unsprung area subject to high vibration requirements. Furthermore, it requires complex logic to estimate the electric motor's winding temperature from the temperature in its vicinity.

[0039] For example, the method described in patent literature 1 requires that the initial winding resistance of an electric motor must be measured beforehand for each product using a sensitive measuring device for measuring low-order resistance, which increases the number of steps in the manufacturing process and thus increases the manufacturing costs.

[0040] In contrast to patent literature 1, the braking device according to the invention (electric braking device 1) and the motor control device (motor control device) comprise 20 ) the temperature sensing sections (first and second temperature sensing section) 23 and 24 ) at least two positions that are affected by the temperature change tendency on the control board 20a , which drive the electric motor 11The invention controls and differentiates between different temperature ranges. Therefore, the invention does not require a special temperature sensor that needs to be placed directly near the electric motor. Furthermore, the invention allows for a more direct estimation of the electric motor's temperature (winding temperature). 11 taking into account the control of the electric motor 11 The invention allows for the determination of the electric motor's winding temperature without requiring complex logic to estimate the motor's winding temperature from the temperature in its vicinity. 11 to estimate with high accuracy using a simpler and more compact logic.

[0041] The braking device (electric braking device 1) and the engine control device (engine control device) 20 ) according to the present embodiment, estimate the temperature of the electric motor11 depending on the ambient temperature, which is based on the outputs of the temperature sensing sections (first and second temperature sensing section) 23 and 24 ) is obtained. This eliminates the need for prior measurement of the electric motor's winding resistance for each product by using a sensitive measuring device to measure the low-order resistance during the manufacturing process of the electric braking device 1 and / or the motor control device. 20 , which limits or eliminates an increase in the number of steps in the manufacturing process and thus an increase in manufacturing costs.

[0042] In the braking device (electric braking device 1) and the engine control device (engine control device) 20 ) according to the present design, the first temperature detection section 23in the heat-generating section on the control board 20a or located near the heat-generating section, and the second temperature sensing section 24 is located in the non-heat-generating section of the control board 20a or at a location away from the heat-generating section of the control board 20a arranged. This makes it possible to control the ambient temperature (i.e., the initial temperature of the electric motor). 11 ) and thus the initial temperature (winding temperature) of the electric motor 11 to estimate with high accuracy as such a value that the values ​​from the first and second temperature measurement sections 23 and 24 The obtained temperatures converge over time, allowing for an accurate estimation of the current temperature (winding temperature) of the electric motor. 11 This enables a protective operation for the electric motor. 11to reliably carry out, which is required at high temperatures, such as during a gradual reduction in power or the like.

[0043] In the braking device (electric braking device 1) and in the engine control device (engine control device) 20 ) according to the present explanation, the winding resistance of the electric motor is 11 measured without the electric motor 11 The d-axis is rotated by excitation when the vehicle stops (including the situation in which the initial resistance is established). In this way, it is possible to measure the winding resistance (e.g., the initial resistance Ri and the current resistance Rc when the vehicle stops) without causing any discomfort to the vehicle user and with high accuracy (e.g., without interference from constant torque changes).

[0044] In the following, a braking device 60 according to a second embodiment of the invention is described with reference to Fig. Section 4 explains, with the focus on the differences from the first embodiment. Components and sections that are similar to or correspond to those of the first embodiment are designated with the same terms and reference numerals as in the first embodiment.

[0045] The braking device 60 is a hydraulic braking device that exerts a braking force on each wheel by rotating a disc D compresses, which rotates with each wheel of a vehicle not shown. The braking device 60 includes a braking mechanism. 61 with the brake pads 2 and 3 , which against the window D be pressed, and a piston 4 , which is arranged slidingly in an inner circumference of a cylinder 66 of a saddle 5 and the brake pads 2 and3 moved. The braking mechanism 61 is provided for each wheel braked by the braking device 60.

[0046] The braking device 60 further comprises a master cylinder 67, which generates hydraulic pressure that is supplied to the cylinder 66 of the caliper 5, and an electric booster device 70 that acts on the master cylinder 67. The electric booster device 70 comprises an electric motor. 11 , which drives an amplifier piston (not shown) that is able to adjust the hydraulic pressure in the main cylinder 67, and a mechanism 72 for converting the rotation into a linear motion, which controls the rotation of the electric motor 11converts the current into a linear motion and transmits this linear motion to the amplifier piston. The electric amplifier unit 70 is capable of implementing various brake control systems, such as regenerative cooperative control, brake assist, and automatic braking, using the electric motor. 11 , which is controlled by an engine control device 20 is driven, which is later described in connection with the pressing down of a brake pedal, is not shown, or is described independently of the actuation of the brake pedal.

[0047] The braking device 60 includes the engine control device. 20 , which control the operation of the electric motor 11 controls the electric motor. 11 , which is controlled by the motor control device 20 The drive is used to generate the hydraulic pressure in the main cylinder 67 and thus to generate the braking force in the braking mechanism. 61used on every wheel.

[0048] The electric motor 11 The braking device 60 resembles the corresponding element of the electric braking device 1 of the first embodiment. The motor control device 20 in the braking device 60 functions with regard to the drive of the electric motor 11 similar to the engine control device 20 the electric brake 1 of the first embodiment.

[0049] With the configuration discussed above, the brake device 60 and the engine control device offer 20 the same functionality and the same advantageous effects as discussed above with regard to the electric braking device 1 and the motor control device according to the first embodiment.

[0050] The control device according to the invention 20 of the electric motor 11was discussed in relation to the vehicle's braking system. However, the device according to the invention for controlling the electric motor is not limited to what was discussed above. On the contrary, the device according to the invention for controlling the electric motor is applicable, for example, to other systems in the vehicle, such as an electric drive system and an electric power steering system, and furthermore to other devices that are not installed in the vehicle. The invention is also applicable to systems in which the electric motor 11 and the control device 20 are arranged at a distance from each other.

[0051] The invention is not limited to the embodiments discussed above and can be modified in various ways. For example, the embodiments describe the invention in detail to facilitate understanding and do not necessarily have to include all the embodiments mentioned above. It is possible to partially replace the embodiment of one embodiment with that of another, and also to incorporate the embodiment of one embodiment into that of the other. The embodiment of each embodiment can be partially combined with or replaced by that of the other embodiment, and can also be deleted.

[0052] The present application claims priority from Japanese patent application No. 2018-060443, filed on March 27, 2018. The entire disclosure of Japanese patent application No. 2018-060443, filed on March 27, 2018, including the description, claims, figures, and abstract, is incorporated herein by reference in its entirety. Reference symbol list 1 Electric braking device (braking device) 2, 3 Brake pad (brake element) 4 pistons 11 Electric motor 10, 61 Braking mechanism 20 Motor control device 20a Control board 23 First temperature recording section (temperature recording section) 24 Second temperature measurement section 43 Ambient temperature D disc (braked element) QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 10100913

[0003] JP 2018060443

[0052]

Claims

[1] Control device for an electric motor comprising: a control board designed to control the drive of an electric motor, and Temperature sensing sections arranged on the control board at at least two positions that differ in their tendency to change temperature. [2] Control device for an electric motor according to claim 1, wherein the control device for the electric motor is configured to estimate the temperature of the electric motor on the basis of the ambient temperature obtained from the output signals of the temperature sensing sections. [3] Control device for an electric motor according to claim 1, wherein the control device for the electric motor is configured to estimate the temperature of the electric motor on the basis of the ambient temperature obtained from the output signals of the temperature sensing sections and to control the electric motor. [4] Control device for an electric motor, wherein the control device for the electric motor is configured to estimate the temperature of an electric motor on the basis of the ambient temperature obtained from the output signals of at least two temperature sensing sections which differ in their tendency to change temperature, and to control the electric motor. [5] Braking system comprising: an electric motor configured to press a braking element against an element to be braked in order to generate a braking force, and a control board designed to control the drive of the electric motor, the control board comprising: a first temperature sensing section, which is located on the control board and is set up to sensing the temperature, and a second temperature sensing section, which is located on the control board at a position where the temperature differs in its rate of change from the temperature detected by the first temperature sensing section. [6] Braking device according to claim 5, wherein the first temperature sensing section is located in or near a heat-generating section of the control board, and wherein the second temperature sensing section is located in a non-heat-generating section of the control board or at a position on the control board remote from the heat-generating section.