INPUT STAGE FOR A MOTOR CONTROLLER, AND MOTOR CONTROLLER, ESPECIALLY FOR AN ELECTRIC MOTOR

Abstract

The invention relates to an input stage (1) for a motor controller (2), especially a motor controller for an electric motor, the input stage (1) being provided with an input (3) for inputting an input signal and an output (4) for connection to the motor controller (2). The input stage (1) is designed to generate a control signal from an input signal between a first voltage U.sub.unten and a second voltage U.sub.oben and output said control signal as a parameter to the motor controller (2) via the output (4). In order to be able to simultaneously use the control input (13) for communicating, the input stage (1) comprises a first comparator (5) for comparing the input signal with a first threshold voltage U.sub.s1>U.sub.oben as well as a data output unit (10). The data output unit (10) generates a communication signal on the basis of at least one portion of the input signal. When the input signal reaches or exceeds the first threshold voltage U.sub.s1, the first comparator (5) outputs an activation signal which activates output of the communication signal to the output (4) by the data output unit (10). The invention further relates to a motor controller, especially for an electric motor, comprising a corresponding input stage, and to an interface adapter for the input stage.

Claims

1. An input stage for a motor controller, in particular a motor controller for an electric motor, wherein the input stage (1) has an input (3) for inputting an input signal, and an output (4) for connecting to the motor controller (2), wherein the input stage (1) is designed to generate a control signal from an input signal between a first voltage U.sub.unten and a second voltage U.sub.oben>U.sub.unten, and to output the control signal as a target value parameter to the motor controller (2) via the output, characterized by a first comparator (5) for comparing the input signal with a first threshold voltage U.sub.S1>U.sub.oben, and a data output unit (10), wherein the data output unit (10) generates a communication signal on the basis of at least a portion of the input signal, wherein the first comparator (5) outputs an activation signal when the first threshold voltage U.sub.S1 has been reached or exceeded by the input signal, which activates an outputting of the communication signal to the output (4) by the data output unit (10).

2. The input stage according to claim 1, characterized in that the data output unit (10) generates the communication signal from the portion of the input signal that is greater than or equal to the first threshold voltage U.sub.S1.

3. The input stage according to claim 1 or 2, characterized in that a first switch device is provided for activating the output of the communication signal to the output (4) by the data output unit (10), wherein the first switch device (7) has two inputs, wherein one of the two inputs of the first switch device (7) is connected to the data output device (10), and wherein the control signal is at least temporarily applied to the second of the two inputs.

4. The input stage according to claim 3, characterized in that the first switch device (7) is designed such that when the activation signal falls below a switching level, the control signal is present at an output of the first switch device (7), and when the activation signal exceeds the switching level, the communication signal is present at the output of the first switching device (7).

5. The input stage according to one of the claims 1 to 4, characterized in that the data output unit (10) comprises a second switching device (8) and a second comparator (6) for comparing the input signal with a second threshold voltage U.sub.S2>U.sub.S1, wherein the second comparator (6) outputs a switching signal to the second switch device (8) when the second threshold voltage U.sub.S2 has been reached or exceeded.

6. The input stage according to claim 5, characterized in that the second switch device (8) has two inputs, wherein a first logic signal is present at one of the two inputs, and a second logic signal is present at the other of the two inputs, wherein the first logic signal and the second logic signal represent complementary logic values, wherein the first logic signal preferably has a high level and the second logic signal preferably has a low level.

7. The input stage according to claim 5 or 6, characterized in that the second switch device (8) is designed such that when the switching signal exceeds a switching level, the first logic signal is present at the output of the second switch device (8), and in that when the switching signal exceeds the switching level, the second logic signal is present at the output of the second switch device (8).

8. The input stage according to one of the claims 1 to 7, characterized in that the input stage (1) has an analog-to-PWM converter (9) for generating the control signal from the input signal, which generates a PWM signal—pulse width modulated signal—from the input signal, wherein the PWM signal preferably has a fixed frequency, and wherein the voltage value of the input signal is preferably encoded in a phase control factor of the PWM signal.

9. A motor controller, in particular for an electric motor, having an input stage according to one of the claims 1 to 8, wherein the input stage (1) is connected to a control input of the motor controller (2), wherein the motor controller (2) controls a motor connected to the motor controller (2) on the basis of a control signal received via the control input, such that a target value encoded in the control signal is at least approximately maintained, characterized in that the motor controller (2) has means for detecting a communication signal present at the control input, and in that the motor controller (2) is designed to switch to a configuration mode when a communication signal has been detected at the control input, and to process the received communication signal.

10. The motor controller according to claim 9, characterized in that the means for detecting a communication signal are configured to evaluate the frequency of a signal at the control input, wherein a control signal is indicated when a first frequency has been detected, and a communication signal is indicated when a second frequency has been detected.

11. The motor controller according to claim 9 or 10, characterized by a message output (14) for outputting status information, wherein the motor controller is configured to use the message output (14) as a communication line when in the configuration mode, for sending responses to a received communication signal.

12. The motor controller according to one of the claims 9 to 11, characterized in that the motor controller (2) is configured to detect a termination signal in the communication signal, wherein the motor controller is configured to end the configuration mode when a termination signal has been detected.

13. An interface adapter for connection to an input stage according to one of the claims 1 to 8, having a first interface and a second interface, wherein the first interface can be connected to an end device, in particular a programming device, wherein the second interface can be connected to the input stage, and wherein the interface adapter converts data received via the first interface to an input signal for the input stage, and outputs this data to the input stage.

Description

[0028] There are thus various possibilities for developing and refining the teachings of the present invention in an advantageous manner. For this, reference is made on one hand to the Claims subordinate to Claims 1 and 9, and on the other hand to the following explanation of a preferred exemplary embodiment of the invention based on the drawings. Generally preferred developments and refinements of the teachings shall also be explained in conjunction with the explanation of the preferred exemplary embodiment of the invention based on the drawings. Shown in the drawings, the single

[0029] FIGURE shows a schematic illustration of an exemplary embodiment of an input stage for a motor controller, according to the invention.

[0030] The single FIGURE shows an exemplary embodiment of an input stage 1 according to the invention, which is connected to a motor controller 2. The input stage 1 has an input 3 and an output 4. A first comparator 5, a second comparator 6, a first switch device 7 and a second switch device 8, as well as an analog-to-PWM converter 9 are contained in the input stage. The input 3 is connected to the non-inverting input of the first comparator 5, the non-inverting input of the second comparator 6, and the analog input of the analog-to-PWM converter 9. A first threshold voltage U.sub.S1=13 V is applied to the inverting input of the first comparator 5. A second threshold voltage U.sub.S2=15 V is applied to the inverting input of the second comparator 6. In this manner, the first comparator 5 compares an input signal present at the input 3 with a first threshold voltage U.sub.S1 of 13 volts, while the second comparator 6 compares the input signal with the second threshold voltage U.sub.S2 of 15 volts. The output of the first comparator 5 is connected to the switch input of the first switch device 7, and the output of the second comparator 6 is connected to the switch input of the second switch device 8. The PWM output of the analog-to-PWM converter 9 is connected to one of the inputs of the first switch device, which is applied, without a switching signal being present, to the output of the first switch device. The second input of the first switch device 7 is connected to the output of the second switch device 8. A first logic signal and a second logic signal are present at the inputs of the second switch device, which are symbolically indicated with a “1” for a logical 1 and a “0” for a logical 0. With a control voltage lying below a switching level at the switch input of the second switch device 8, the first logic signal is activated at the output in the standard manner, corresponding to a logical 1. The second comparator 6 and the second switch device 8 collectively form the data output unit 10.

[0031] When there is a voltage of less than 13 volts at the input 3 of the input stage 1, there is a voltage at the output of the first comparator and at the output of the second comparator that is less than the switching threshold for the first switch device 7 and the second switch device 8. The first switch device 7 is thus in the home position, in which the signal of the analog-to-PWM converter 9 is applied to the output of the switch device 7 and thus to the output of the input stage 1. The analog-to-PWM converter 9 has a working range between a first voltage U.sub.unten=0 V and a second voltage U.sub.oben=10 V. The PWM signal outputted by the analog-to-PWM converter 9 has a fixed frequency of 1 kHz, wherein the phase control factor is selected depending on the voltage applied to the analog input. In the present exemplary embodiment, the phase control factor is 25% with a voltage of 0 V, which increases in a linear manner as the input voltage increases, until a voltage of 10 V and a phase control factor of 75% is obtained.

[0032] When a communication signal is to be sent to the motor controller 2, the input signal must have a voltage that is suitable for activating the first switch device 7. Because the first threshold voltage U.sub.S1 selected in the exemplary embodiment is 13 V, the input voltage applied to the input 3 must reach or exceed a voltage of 13 V. When the voltage of 13 V has been reached or exceeded, the first comparator 4 outputs an activation signal to the control input of the first switch device 7, which causes the first switch device 7 to switch to the other input of the first switch device 7. As a result, a signal generated by the data output unit 10 is present at the output 4 of the input stage 1, and the outputting of a communication signal by the data output device is activated at the output of the input stage. In the selected design, a logical 1 is outputted to the motor controller 2. If the input signal reaches or exceeds a voltage of 15 V, the second comparator 6 outputs a switching signal to the second switch device 8, by means of which the second switch device 8 is switched to the other input, corresponding to a logical 0. Thus, with a voltage greater than 13 V and less than 15 V, a logical 1 can be encoded in the input signal, and with a voltage greater than 15 V, a logical 0 can be encoded in the input signal. It would be conceivable, for example, to encode a logical 0 in the input signal with a voltage of 14 V, and a logical 0 in the input signal with a voltage of 16 V. In this manner, the input stage 1 according to the invention can output the currently typical control voltage between 0 and 10 volts to the motor controller 2 as a control signal, and at the same time, transmit a communication signal to the motor controller when the voltage is greater than 10 volts.

[0033] The output 4 in the input stage 1 is connected to a control input 11 of the motor controller 2. Means for detecting the frequency of the signals present at the input 11 are implemented in the motor controller when it is in operation. These means indicate the application of a control signal with a signal frequency of 1 kHz, for example. The target value encoded in the control signal, e.g. a target rotational rate, is processed appropriately by the motor controller, and regulates the motor connected to the motor controller to the target rotational rate. If the communication pathway is activated due to the voltage level in the input signal, this frequency is then no longer present at the input 11 of the motor controller 2. This can be used for detecting a configuration mode. Alternatively, the frequency of the communication interface can be established such that it is significantly higher than the frequency of the PWM signal, e.g. greater than or equal to 9 kHz. The motor controller 2 determines, on the basis thereof, whether there is an analog control signal or a communication signal at the input of the input stage.

[0034] When a communication signal has been detected at the input 11 of the motor controller 2, the evaluation of the analog control signal is terminated, and the input 11 is reconfigured to a data input RxD. The motor controller is then switched to a configuration mode. As long as the motor connected to the motor controller is still in motion, the motor can be brought into a safe operating mode, e.g. it can be brought to a standstill. Alternatively, the motor could continue to rotate at the previously inputted target rotational rate, until the motor controller returns to a normal operating mode, and the control input is again evaluated. The motor controller 2 also has a message output 12, via which status messages regarding the motor and/or the motor controller connected thereto can be outputted when in the normal operating mode. When the configuration mode is activated, the message output 12 is reconfigured to a transmission line TxD.

[0035] In order to input a control signal, and for communication, an appropriate input device (not shown) is connected to a control input 13 and a message output 14. When the motor controller controls an EC motor with a ventilator, for example, a regulator can be connected to the control input, which receives status information regarding the motor via the message output 14. In the normal operating mode, the regulator generates an input signal between 0 V and 10 V, and inputs this to the control input 13 in the present exemplary embodiment. The control input 13 is connected to the input 3 of the input stage 1.

[0036] In order to configure the motor controller, an appropriate communication signal must be inputted. For this, a communication device can be connected, instead of the regulator. This communication device can either generate an appropriate modulated communication signal directly, or it can be connected to an interface adapter. The interface adapter can have a standard interface at the input side, e.g. an RS-485 interface. At the output side, the interface adapter is connected to the control input 13 and the message input 14. When a logical 1 is received via the RS-485 interface, the interface adapter converts this to a voltage of 14 V for example. With a logical 0 at the RS-485 interface, the interface adapter outputs a voltage of 16 V, for example. The interface adapter thus functions as an amplitude modulator. Accordingly, the interface adapter can convert a signal received via the message output into an RS-485 signal. In this manner, a conventional communication device having an RS-485 interface can be connected to the motor controller according to the invention using an interface adapter.

[0037] In the exemplary embodiment illustrated in the FIGURE, the state of the configuration mode remains intact until the motor controller 2 has been reset. An analog control signal can first be evaluated again in the motor controller 2 after the reset.

[0038] The installation costs can be kept to a minimum with the design of the input stage according to the invention and the motor controller according to the invention described herein. As a result of the interface adapter, there is a minimal number of components required in the input stage, which in turn has a positive effect on the overall costs. As a result, the input stage can be used in small and inexpensive ventilators. Anything necessary for implementing an interface in an industry standard can be disposed outside the ventilator in the interface adapter. This interface adapter is mobile, and can be removed after it has been used. For applications in which modifications are frequently carried out, for example, the interface adapter can also be stationary, i.e. it can remain with the device.

[0039] With regard to further advantageous designs of the input stage according to the invention, or the motor controller according to the invention, reference is made to the general part of the description, as well as to the attached claims, in order to avoid repetition.

[0040] Lastly, it should be expressly noted that the description of exemplary embodiment above serves only for a discussion of the claimed teachings, but these are not limited to the exemplary embodiment.

LIST OF REFERENCE SYMBOLS

[0041] 1 input stage [0042] 2 motor controller [0043] 3 input [0044] 4 output [0045] 5 first comparator [0046] 6 second comparator [0047] 7 first switch device [0048] 8 second switch device [0049] 9 analog-to-PWM converter [0050] 10 data output unit [0051] 11 control input/RxD [0052] 12 message output/TxD [0053] 13 control input [0054] 14 message output