CN109586618B

CN109586618B - Driving system for electrical equipment

Info

Publication number: CN109586618B
Application number: CN201710910613.2A
Authority: CN
Inventors: Y-L·阿莱尔特; P·鲁奥尔特; 王成月
Original assignee: Schneider Electric Industries SAS
Current assignee: Schneider Electric Industries SAS
Priority date: 2017-09-29
Filing date: 2017-09-29
Publication date: 2022-10-04
Anticipated expiration: 2037-09-29
Also published as: CN109586618A

Abstract

The present disclosure provides a drive system for an electrical device. According to an embodiment of the present disclosure, the drive system includes a power cell array including a plurality of power cells for different phases. At least one of the power cells for at least one phase in the array of power cells is configured to disconnect the supply of power on the respective phase to perform a safe torque off operation in response to receiving a safe torque off signal. According to the embodiment of the present disclosure, a safe torque-off operation of the electrical device can be achieved, providing a required level of safety.

Description

Driving system for electrical equipment

Technical Field

Embodiments of the present disclosure relate to electrical device driving technology, and more particularly, to a power unit and a driving system for an electrical device.

Background

To prevent a personal injury accident due to an accidental start of electrical equipment, an STO function has been proposed for products such as a frequency converter, a servo motor driver, and the like. This function can prevent the drive from generating torque in it when, for example, the motor is stopped, thereby enabling the motor to be part of the safety system. The STO function is now becoming more and more necessary and even tends to be the driving standard function.

The STO function is typically present in existing low voltage drive systems. In low voltage drive systems, two or three dedicated lines or printed circuit board traces are typically provided which are used to transmit STO control signals from a user via customer terminals to the power cell in order to control insulated gate transistors IGBT in the power cell, thereby allowing the drive output to be turned off in an emergency, causing, for example, the motor apparatus to shut down. The power unit is a high-voltage frequency converter component which uses power electronic devices to carry out rectification, filtering and inversion. Which typically includes semiconductor devices arranged in a full bridge configuration, such as insulated gate transistors (IGBTs), a STO control signal is provided to the gate of the IGBT to control the IGBT to turn off.

For safety reasons, however, it is necessary to isolate the STO control signals, since the STO signal is triggered by the user on the one hand, and on the other hand will be transmitted to the high voltage area, so that there is a possibility that the user will be exposed to a dangerous high voltage. In low voltage drive systems, such isolation may be achieved by optical coupling.

There is also a need for an STO function in medium voltage drive systems. However, no suitable drive technology for the medium voltage system has been proposed in the prior art to achieve the STO function.

Disclosure of Invention

In view of the above, the present disclosure provides a new driving scheme for an electrical device to overcome or alleviate at least some of the drawbacks of the prior art as described above.

According to one aspect of the present disclosure, a drive system for an electrical device is provided. The drive system may include: a power cell array comprising a plurality of power cells for different phases. At least one of the power cells for at least one phase in the array of power cells is configured to disconnect the supply of power on the respective phase to perform a safe torque off operation in response to receiving a safe torque off signal.

According to one embodiment, at least one of the power units for one of the different phases may be configured to perform the safe torque off operation.

According to another embodiment, at least one of the power units for each of the different phases may be configured to perform the safe torque-off operation.

According to a further embodiment, the at least one power unit for performing the safe torque shutdown may comprise: a semiconductor device, and a communication monitoring module. The communication detection module may be configured to monitor communication data on a communication line in an electrical system and, in response to detecting that information indicative of a safe torque shutdown is included in the communication data, provide a shutdown signal for the safe torque shutdown to the semiconductor device.

According to the embodiment of the present disclosure, a safe torque-off operation of the electrical device can be achieved, providing a required level of safety. Moreover, in some embodiments, it may be implemented in a simple, low-cost manner.

Drawings

The foregoing and other features of the disclosure will be apparent from the following more particular description of embodiments as illustrated in the accompanying drawings in which like reference characters refer to the same or similar parts throughout the different views. In the drawings:

fig. 1 schematically illustrates a block diagram of an example medium voltage drive system for an electrical apparatus, according to an embodiment of the present disclosure;

FIG. 2 schematically illustrates a block diagram of another example medium voltage drive system for an electrical device, according to an embodiment of the present disclosure;

FIG. 3 schematically illustrates a block diagram of a user interface control device according to one embodiment of the present disclosure;

fig. 4 schematically illustrates a block diagram of a power cell according to an embodiment of the present disclosure;

FIG. 5 schematically illustrates a block diagram of an example communication monitoring module, according to an embodiment of this disclosure;

FIG. 6 schematically shows a timing diagram illustrating the generation of the STO control signal according to one embodiment of the present disclosure;

FIG. 7 schematically illustrates a block diagram of another example communication monitoring module, according to an embodiment of the present disclosure;

FIG. 8 schematically illustrates a block diagram of yet another example communication monitoring module, according to an embodiment of this disclosure;

FIG. 9 schematically illustrates a flow chart of a method for processing an STO control signal according to one embodiment of the present disclosure; and

fig. 10 schematically shows a flow chart of a method for STO according to one embodiment of the present disclosure.

Detailed Description

Hereinafter, various exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that the drawings and the description relate to preferred embodiments by way of example only. It should be noted that from the following description, alternative embodiments of the structures and methods disclosed herein are readily contemplated and may be employed without departing from the principles of the disclosure as claimed in the present disclosure.

It should be understood that these exemplary embodiments are given solely for the purpose of enabling those skilled in the art to better understand and to practice the present disclosure, and are not intended to limit the scope of the present disclosure in any way. Also in the drawings, optional steps, modules, etc. are shown in dashed boxes for illustrative purposes.

The terms "including," comprising, "and the like, as used herein, are to be construed as open-ended terms, i.e.," including/including but not limited to. The term "based on" is "based, at least in part, on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment". Relevant definitions for other terms will be given in the following description.

As mentioned before, there is also a need for an STO function in medium voltage drive systems. However, no suitable drive technology for the medium voltage system has been proposed in the prior art to achieve the STO function. To this end, a new drive system for an electrical device is provided in the present disclosure. The drive system may include: a power cell array comprising a plurality of power cells for different phases. At least one of the power cells for at least one phase in the array of power cells is configured to disconnect the supply of power on the respective phase to perform a safe torque off operation in response to receiving a safe torque off signal. In other words, for the power cell array of the drive system, at least one of the power cells for at least one phase therein is set to be able to perform a safe torque off operation in response to the STO signal, thereby implementing the STO function.

It should be noted that the STO function can be implemented with a power unit in a similar manner to the low voltage drive system. Furthermore, it can be implemented using new power cells. It will be appreciated that the system of the medium voltage drive system is more bulky and complex than the low voltage drive system, and that achieving STO in the same manner requires increased costs. For this purpose, the STO function can be implemented with an improved power cell, in particular for medium voltage systems, wherein the STO control signal is carried, for example, by means of communication data. In the following, reference will be made mainly to power units particularly for medium voltage systems.

Fig. 1 schematically shows a block diagram of an example medium voltage drive system for an electrical apparatus, wherein one of the power units for one of the different phases is configured to perform the safety torque off operation, according to an embodiment of the present disclosure.

As shown in fig. 1, in a medium voltage drive system 100, a user interface control board 101 provides I/O interface control functions between a user and the system. The user interface control board 101 may receive an STO control signal from a user. In response to the STO control signal, the user interface control board 101 may generate information indicating the STO control signal and include the information in communication data to be transmitted to the fiber board 106 through the communication line. The microcontroller 102 may be used to control the processing of user I/O data, e.g., may inform the PFGA to perform corresponding operations, logical operations. The signal conditioning board 105 receives the measured values, e.g., voltage, current, etc., converts them to suitable values and then performs analog-to-digital conversion by the Σ Δ module 104, with the converted digital signal being provided to the FGPA103 for processing. Fiber optic board 106 receives communication data from user interface controller 101, FPGA103, where Complex Programmable Logic Device (CPLD) 107 splits and time-sequences the signals before providing them to power cell POC array 120.POC array 120 includes multiple power units 121-129 for different phases. The POC array 120 shown is a 3X3 array for three phases, three POC for each phase. Power from transformer 130 is provided to POC 121to 129.

In this POC array, one of the POC 124 is an STO-enabled POC that can monitor communication data on a communication line in an electrical system to see if information indicating safe torque shutdown is included in the communication data, and provide a shutdown signal for safe torque shutdown to semiconductor devices within the power unit in response to detecting that information indicating safe torque shutdown is included in the communication data.

Note that the POC with STO functionality in the POC array may be any one of the phases. If one POC with an STO function is used in the POC array, an STO shutdown function can be provided on one phase, which can achieve safe torque shutdown of the motor 140. This can achieve a safe level of STO SIL 1. Furthermore, it is also possible to provide more than one POC with STO on one phase.

Further, it is also conceivable to provide a power unit having an STO function on each of the three phases. A block diagram of another example medium voltage drive system for an electrical device according to an embodiment of the present disclosure will be described below with reference to fig. 2.

The system architectures of fig. 2 and 1 are substantially similar, but differ in that POC 124, POC 128, POC 123, which are located on different phases, respectively, in the POC array are STO-enabled POC, i.e. there is one STO-enabled POC in each phase, and each of these POCs can monitor communication data on the communication line in the electrical system to see if information indicating safe torque shutdown is included in the communication data, and provide a shutdown signal for safe torque shutdown to the semiconductor devices within the power unit in response to detecting that information indicating safe torque shutdown is included in the communication data. The operation of the other components is substantially similar to that of the components shown in fig. 3 and will not be described again here.

It should be noted that the inclusion of a POC with an STO function in each phase of a POC array may be any one of the phases. Using one POC with an STO function for each phase in the POC array, an STO turn-off function can be provided on each phase, which can provide zero voltage on all three phases in case of safe torque turn-off of the motor 140. This can achieve a safe level of STO SIL 2. Furthermore, it is also possible to provide more than one POC with STO on one phase.

Further, as previously described, the STO function can be implemented for the drive system of the present invention in the same manner as for the low voltage drive system. However, it may be necessary to add a large number of signal cables to transmit the required STO signal, which makes the system large and complex, and the resulting increase in cost is high, and the safety isolation is not easy to implement in a simple manner. For this reason, in the present disclosure, it is also proposed to carry STO control information through a communication line. According to this scheme, information indicative of the STO will be included in the communication data for transmission on the communication line, and an enable signal for the STO will be provided to the semiconductor devices (e.g., IGBTs) in the power cells by monitoring the information indicative of the STO in the communication data.

Hereinafter, an example embodiment for implementing the user interface board and the POC shown in fig. 1 and 2 will be described in detail with reference to fig. 3 to 10. It should be noted, however, that the embodiments illustrated in the drawings and described below are given for illustrative purposes and the present disclosure is not limited to the illustrated embodiments.

Referring first to fig. 3, fig. 3 schematically illustrates a block diagram of a user interface control device 300 according to one embodiment of the present disclosure. The user interface control device 300 is one example device, such as the user interface control panel 101 shown in fig. 1 and 2, for receiving input from a user and providing system output to the user. The control board may receive power-on and power-off signals from a user (e.g., via a power button by the user), and may also receive an STO control signal from the user. For example, the user may be provided with two STO buttons, either of which can trigger the STO control signal. Here, safety redundancy can be achieved by providing two STO buttons. However, it will be appreciated that it is also possible to provide only one STO button. It should also be noted that it is also possible to implement the STO button as a virtual button on the touch screen, or in the case of two STO buttons, one of which is a virtual button and the other a mechanical button.

The STO control signal from the subscriber can be received by the signal processing module 301. However, unlike the conventional transmission of the STO control signal over a dedicated line, the signal processing module 301 is configured to add information indicating the STO to the communication data for transmission over the communication line in response to receiving the STO control signal from the subscriber. In other words, the signal processing module 301 is responsible for converting the control signal indicating the enabling of the STO from the subscriber into the information indicating that the STO needs to be enabled, which is to be transmitted through the communication line as the communication data, contained in the communication data. For example, the information indicating the STO may have a pattern different from that of the general communication data so that it can be recognized.

At the power unit, on the other hand, the communication data on the communication line is monitored to detect the information contained therein indicating that STO needs to be enabled. When this information is detected, the power unit will know that the user desires to enable the STO function. Next, a power unit provided in the present disclosure will be described with reference to fig. 4 to 8.

Referring to fig. 4, a block diagram of a power cell 400 is shown, according to one embodiment of the present disclosure. As shown in fig. 2, the power unit 400 is a high voltage inverter component that performs rectification, filtering, and inversion using power electronics, and includes a communication monitoring module 401 and a semiconductor device 402. The semiconductor devices 402 are, for example, insulated gate transistors (IGBTs), which may be arranged in a full-bridge configuration. The circuit structure of semiconductor devices arranged in a full-bridge manner in a power cell is known and will not be described herein.

In addition, it should be noted that the following description will use IGBTs as examples of the semiconductor device 402, however, it is understood that they may also use other types of semiconductor devices, or other topologies. For an IGBT, a voltage applied at the gate of the IGBT may control the IGBT to turn on and off.

The communication monitoring module 401 has input terminals to which communication data on a communication line is transmitted, which may be configured to monitor the input communication data, and to provide a shut down signal for safe torque shut down to the semiconductor device at the output terminals in response to detecting that information indicating safe torque shut down is contained in the communication data.

The communication monitoring module 401 may be implemented in various ways, such as digitally, or using analog. Hereinafter, for the purpose of explanation, embodiments of the present disclosure are described by specific examples.

Referring to fig. 5, an example communication monitoring module 401 'is shown, which communication monitoring module 401' implements communication system monitoring by counting high and low levels of communication data, according to one embodiment of the present disclosure. As shown in fig. 5, the communication monitoring module 401' may include two counters, i.e., a high level counter 4011 and a low level counter 4012. The high level counter 4011 is configured to count a high level in the communication data. The low level counter 4012 is configured to count a low level in the communication data. Clock sources 2013a and 2013b are two clock sources, which respectively supply clock signals to the high level counter 4011 and the low level counter 4012 so that the two counters count. The high level counter 4011 and the low level counter 4012 may be implemented using the same counter, but in this case, an inverter for inverting the input data is used before the communication data input terminal of the low level counter 4012, thereby implementing counting of low levels.

The high level counter 4011 provides a high level signal as a counter output signal at its output terminal if the count of the high level reaches a corresponding predetermined threshold; the low level counter 4012 also provides a high level signal as a count indication signal at its output terminal if the count of said low level reaches a corresponding predetermined threshold. Outputs of the low level counter 4012 and the high level counter 4011 are supplied to the signal generating section 4014. The signal generating section 4014 is configured to provide a shutdown signal for safe torque shutdown based on the count indication signal of the high level at the output of any one of the high level counter and the low level counter. One example of the signal generating section 4014 is an or gate. The or-gate performs, for example, an or operation on the two counter output signals, and provides a high level signal at its output as a shutdown signal for STO, i.e., an STO enable signal, as long as either one of them is high. The STO signal may be provided to the semiconductor device 402, in particular to the gate of the IGBT, in order to put the semiconductor device in an off-state, thereby performing the STO function.

In addition, the communication monitoring module 401' may also send a signal to a main controller (not shown) of the power unit indicating that the safe torque off function is active. The generated STO control signal may be provided simultaneously to the main controller of the power unit, for example, to inform the main control STO function that is currently enabled and in an active state. In this way, the main controller can stop the processing such as decoding of the communication data.

Furthermore, for the purpose of security isolation, it is also conceivable to provide isolation between the secure part and the non-secure part. For example, it is conceivable to add an isolation unit 4015, such as a diode or a buffer, to a line from the communication monitoring module to the main controller for notifying that the STO function is in a valid state, so that a signal can be transmitted only in the direction from the signal generation unit 4014 to the main controller. Thus, even if the main controller is abnormal, the safety part is not affected.

In addition, it is also conceivable to add an isolation component to the line from the communication data itself to the main controller so as to allow only the transmission of the communication data to the main controller, so that the signal from the main controller does not affect the monitoring result of the communication monitoring module. For example, it is contemplated to add an isolation component 4016, which may also be, for example, a diode or a buffer, on the line of the communication data to the host controller, so that the communication data can only be transmitted in the direction to the host controller, without the signals from the host controller having any effect on the safety section.

In addition, a signal indicating that the safe torque off function is in an active state may be further sent to the electrical system where the power unit is located, so as to inform the electrical system that the safe torque off is currently enabled. The transmission of this signal may be transmitted in a similar manner as the signal to the master controller, i.e. from the communication monitoring module 401'; alternatively, after the master controller receives the signal, the master controller may send a signal to the electrical system indicating that the safe torque off function is in an active state. In response to the signal, the electrical system may display or update the STO enabled status, for example, on a display screen or human machine interface, and may, for example, cease encoding and transmitting of communication data, etc.

It is noted that the level required to turn off the semiconductor device may be different for different types of semiconductor devices. Thus, depending on the nature of the semiconductor device, an inverter may be added before the STO control signal enters the gate to properly place the semiconductor device in the desired state. In addition, it is also conceivable to employ protection redundancy, i.e., it is conceivable to generate another STO signal through another additional set of low level counter 4012 and high level counter 4011 to control the semiconductor device, for example, it may be used to control the upper arm and the lower arm of the full bridge configuration, respectively. Thus, even if one group of circuits is abnormal, the other group of circuits can still work normally to realize the STO function.

Fig. 6 schematically shows a timing diagram for explaining the operation of the communication monitoring circuit according to one embodiment of the present disclosure. As shown in fig. 6, a clock signal 601 and data 602 are shown. The clock signal 601 is, for example, a clock signal supplied from

clock sources

4013a and 4013b to a high level counter and a low level counter. The data 602 is, for example, raw data to be transmitted over a communication line. The data 602 may be counted using a high level counter while the communication data 602 is counted using a low level counter. For example, the communication data 602 may be high-level counted and low-level counted at each rising edge of the clock signal. If the count of any of them reaches a corresponding predetermined threshold, e.g., 8, then an STO enable signal is generated.

In the communication monitoring module shown in fig. 5, both high level counters and low level counters are used, so that the power unit can support the application of a plurality of high levels as STO control information, and also can support the application of a plurality of high levels as STO control information. The STO function may be automatically triggered even when a communication failure at a high level occurs or a communication failure at a low level occurs.

It should be noted that although a specific structure of the communication monitoring circuit is described above, it should be noted that this is merely an example communication monitoring circuit given for illustrative purposes, and other embodiments are possible. Next, two other example communication monitoring circuits will be described with reference to fig. 5 and 6.

Fig. 7 schematically illustrates a block diagram of another example communication monitoring module, according to an embodiment of the present disclosure. As shown in fig. 7, the exemplary communication monitor module 401 ″ is different from the communication monitor module 401' shown in fig. 3 in that it includes only one high level counter 4011, and the high level counter 4011 outputs a high level when a count of the high level exceeds a predetermined threshold, and the high level is supplied as an STO signal to the semiconductor device to perform STO. Other components in fig. 5, such as clock source 4013a,

isolation components

4015 and 4016 perform similar operations and achieve similar functions as the components shown in fig. 3, and are not described herein again for simplicity.

Fig. 8 schematically illustrates a block diagram of yet another example communication monitoring module, according to an embodiment of this disclosure. As shown in fig. 6, an example communication monitoring module 401 '"is similar to the communication monitoring module 401" shown in fig. 5, including only one counter, but including a low level counter 4012 instead of a high level counter differently in the communication monitoring module 401' ". When the count of the low level counter 4012 for the low level exceeds a predetermined threshold, a high level is outputted, which is supplied as an STO signal to the semiconductor device to perform STO. Other components such as clock source 4013b and

isolation components

4015 and 4016 perform similar operations to those shown in fig. 3 and 5, and achieve similar functions, and are not described herein for simplicity.

According to the embodiment of the disclosure, an STO technical scheme based on communication data monitoring is provided, and an extra cable or line is not needed to support the STO function, so that a system with the STO function can have better compatibility with an original system, and meanwhile, the realization mode is simpler and the realization cost is lower. And because the STO control information is carried by the communication line instead of a special line, a user can be isolated from the high-voltage unsafe part, and the safety of the user is protected.

It should be noted that although in the above description the solution proposed in the present invention is directed to a medium voltage drive system, it can in fact be used in other drive systems, such as low voltage systems.

Next, an embodiment of the method provided in the present disclosure will be described with reference to fig. 9 and 10.

FIG. 9 schematically shows a flow diagram of a method 900 for processing an STO control signal according to one embodiment of the present disclosure. As shown in fig. 9, at step 901, the user interface control board receives a control signal from the user for safe torque off. For example, a user issues an STO control signal via an STO button provided by the system, which STO control signal may be received by the user interface control board. After the user interface control board receives the STO control signal, the information indicating safe torque off is included in the communication data in response to the control signal for transmission through the communication line at step 902. This eliminates the need for dedicated lines for transmitting the STO control signal. For example, the information indicating the STO may have a pattern different from that of the general communication data so that it can be recognized.

FIG. 10 schematically shows a flow chart of a method 1000 for STO according to one embodiment of the present disclosure. As shown in fig. 10, a communications monitoring module monitors communications data on a communications line in an electrical system at step 1001. In step 1002, the communication monitoring module provides a shutdown signal for safe torque shutdown to a semiconductor device within the power cell in response to detecting that the communication data includes information indicative of safe torque shutdown. The communication monitoring and shutdown signal generation may be implemented in various ways.

In one embodiment according to the present disclosure, a high level in the communication data is counted, wherein if the count of the high level reaches a predetermined threshold, this means that it is detected that the information indicating safe torque shut-off is included in the communication data, thus providing a shut-off signal for safe torque shut-off. This counting may be achieved by a high level counter, which may provide a high level at the output of the counter, which may serve as a control signal for STO, when the count of said high level reaches a predetermined threshold.

In another embodiment according to the present disclosure, a low level in the communication data is counted, wherein if the count of the low level reaches a predetermined threshold, this means that the information indicating that the safe torque is turned off is detected to be included in the communication data. At this time, a shut-off signal for safe torque shut-off may be provided. This counting may be achieved by a low level counter, which when reaching a predetermined threshold value may provide a high level at the output of the counter, which may be used as a control signal for STO.

In another embodiment according to the present disclosure, the high level and the low level in the communication data may be counted separately, wherein if the count of either of the high voltage and the low voltage reaches a respective predetermined threshold, this means that it is detected that the information indicating safe torque shut-off is included in the communication data. At this point, a shutdown signal for safe torque shutdown may be provided. This high level of counting may be achieved by a high level counter which may provide a high level at the output of the counter when it reaches a predetermined threshold. This low level counting may be achieved by a low level counter which may provide a high level at the output of the counter when the low level count reaches a predetermined threshold. Then, a shut-off signal for safe torque shut-off may be provided based on the count indication signal of high level at the output of either one of the high level counter and the low level counter. For example, an or operation may be performed on the outputs of the high level counter and the low level counter, i.e., if either one of the outputs is high, a high level is output, or the result of the or operation will be a control signal for STO.

In one embodiment according to the present disclosure, a signal indicating that the safety torque off function is in an active state may be further sent to the main controller of the power unit at step 1003. The generated STO control signal may be provided simultaneously to the main controller of the power unit, for example, to inform the main control STO function that is currently enabled and in an active state. Thus, the main controller can stop the processing such as decoding of the communication data.

In one embodiment according to the present disclosure, sending a message to the electrical system indicating that the safe torque off function is active in step 1004 may be further included to inform the electrical system that the safe torque off is currently enabled. The electrical system may display or update the STO enabled status, for example, on a display screen or human machine interface, and may stop encoding and transmitting of communication data, for example.

In one embodiment according to the present disclosure, a safe portion within the power unit for achieving safe torque shutdown may also be isolated from other unsafe portions in the power unit at step 1005. The isolation is achieved by any one of a buffer and a diode. For example, it is considered that an isolating unit 4015 is added to a line to the main controller for notifying that the STO function is in a valid state so that a signal can be transmitted only in the direction from the signal generating unit 4014 to the main controller, and thus, there is no influence on the safety section even when an abnormality occurs in the main controller. In addition, it is also conceivable to add an isolation component to the line from the communication data itself to the main controller so as to allow only the transmission of the communication data to the main controller, so that the signal from the main controller does not affect the monitoring result of the communication monitoring module.

It should be noted that the embodiments of the present disclosure can be realized in hardware, software, or a combination of software and hardware. The hardware portion may be implemented using dedicated logic; the software portions may be stored in a memory and executed by a suitable instruction execution system, such as a microprocessor or specially designed hardware.

It will be appreciated by those skilled in the art that the above described method and apparatus, some of which may be implemented using code embodied in processor control code, may be provided, for example, on a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as read only memory (firmware) or a data carrier such as an optical or electronic signal carrier.

The apparatus and its components of the present embodiment may be implemented by hardware circuits such as a very large scale integrated circuit or a gate array, a semiconductor such as a logic chip or a transistor, or a programmable hardware device such as a field programmable gate array or a programmable logic device, or may be implemented by software executed by various types of processors, or may be implemented by a combination of the above hardware circuits and software, for example, by firmware.

While the present disclosure has been described with reference to presently contemplated embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments. On the contrary, the disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A drive system for an electrical device, comprising:

a power cell array including a plurality of power cells for different phases,

wherein at least one of the power cells for at least one phase in the array of power cells is configured to disconnect the supply of power on the respective phase to perform a safe torque off operation in response to receiving a safe torque off signal;

wherein the at least one power unit for performing the safe torque shutdown comprises:

semiconductor device, and

a communication monitoring module configured to monitor communication data on a communication line in an electrical system and to provide a shutdown signal for safe torque shutdown to the semiconductor device in response to detecting that information indicating safe torque shutdown is included in the communication data;

wherein the information indicative of safe torque shutdown is encoded in the form of a high level and/or a low level and transmitted as the communication data on the communication line.

2. The drive system of claim 1, wherein at least one of the power cells for one of the different phases is configured to perform the safe torque off operation.

3. The drive system of claim 1, wherein at least one of the power cells for each of the different phases is configured to perform the safe torque off operation.

4. The drive system of claim 1, wherein the communication monitoring module is further configured to:

sending a signal to a main controller of the power unit indicating that a safe torque off function is in an active state.

5. The drive system of claim 1, wherein the communication monitoring module is further configured to:

sending information to the electrical system indicating that a safe torque off function is active.

6. The drive system of claim 1, wherein the communication monitoring module comprises a high level counter configured to count high levels in the communication data,

wherein the communication monitoring module detects that the information indicative of safe torque shutdown is included in the communication data if the count of high levels reaches a predetermined threshold.

7. The drive system of claim 1, wherein the communication monitoring module comprises a low level counter configured to count low levels in the communication data,

wherein the communication monitoring module detects that the information indicative of safe torque shutdown is included in the communication data if the count of low levels reaches a predetermined threshold.

8. The drive system of claim 1, wherein the communication monitoring module comprises:

a high level counter configured to count a high level in the communication data and provide a counter output signal of a high level if the count of the high level reaches a predetermined threshold;

a low level counter configured to count low levels in the communication data and to provide a counter output signal of a high level if the count of the low levels reaches a predetermined threshold; and

a signal generating part configured to provide a shut-off signal for safe torque shut-off based on a count indication signal of a high level at an output of any one of the high level counter and the low level counter.

9. The drive system of claim 1, further comprising:

at least one isolation component configured to isolate a safe portion within the power cell for achieving a safe torque shutdown from other unsafe portions in the power cell.

10. The drive system of claim 9, wherein the isolation component comprises any one of a snubber and a diode.

11. The drive system of claim 1, further comprising: a user interface control device, wherein the user interface control device comprises a processing module configured to receive a control signal of the safe torque off from a user, and the processing module is configured to include information indicating the safe torque off in communication data for transmission over the communication line in response to the control signal.

12. A drive system according to any of claims 1to 3, which is a medium voltage drive system.