EA041633B1 - SYSTEM AND METHOD FOR CONTROL OF AUXILIARY DEVICES WITH ELECTRIC DRIVE - Google Patents

Description

Cross-reference to related applications

This application is based on US Provisional Application No. 62/098756, filed December 31, 2014, the contents of which are incorporated herein by reference in their entirety.

Prerequisites for the creation of the invention

Technical field

Embodiments of the invention generally relate to the control of auxiliary devices. Other embodiments relate to a system and method for controlling power assisted devices.

Discussion of the prior art

In the mining industry, large off-highway vehicles (OHVs) typically use electrically motorized wheels to propel or slow the vehicle. In particular, OHVs typically comprise a high power diesel engine coupled with an alternator, a main traction inverter, and a pair of wheel drive assemblies housed within the vehicle's rear wheel tires. The diesel engine drives the rotor of the alternator, which feeds the main traction inverter. The traction inverter contains semiconductor power switches that switch the output current of the alternator to provide electric power to electric drive motors, such as AC motors, wheel drive units.

Also, trains typically contain a number of cars that are pushed or pulled by a locomotive using electric wheel motors to drive the traction wheels. The electric wheel motors are powered by electrical power distribution from one or more generators located in the locomotive.

In both OHV and rail applications, solid state power converters are used to supply high voltage current from generators or alternators to wheel drive motors. Such power converters contain inductors for lowering voltage, as well as semiconductor power switches for switching current. In such systems, cooling of vehicle drive components may be accomplished by using electrically driven cooling systems that include blowers or fans. It is possible, however, that communication between the electrical components within the electrically driven cooling system is interrupted or broken. As will be appreciated, if communication is lost, the system controller may lose control of the cooling system, resulting in potential immobilization of the vehicle.

Thus, it is desirable to provide a system and method for powering auxiliary devices, such as an electrical cooling system, which enables the auxiliary device, such as a blower, to be controlled in the event of a communication failure.

Brief description of the invention

In one embodiment, the vehicle comprises a power source, a controller, a converter configured to receive a first voltage from the power source and convert the first voltage into a second voltage, an auxiliary inverter system electrically connected to the output of the converter and an auxiliary device having an electric motor, wherein the system the auxiliary inverter is configured to convert the second voltage received from the converter to power the electric motor, and the first communication line between the controller and the auxiliary inverter system. The auxiliary inverter system is also configured to control the speed of the motor based on the level of the second voltage in response to the interruption of the first communication line.

In another embodiment, the system includes a controller configured to receive information regarding the mode of operation of the machine, and an accessory device configured to operate in a state that is adequate to the mode of operation of the machine, while the accessory device receives power from a power source. The system also contains at least one communication line between the controller and an auxiliary device, while said line instructs the auxiliary device to operate in a state adequate to the mode of operation of the machine. If at least one communication line is interrupted, the auxiliary device can still operate in a state adequate to the mode of operation of the machine, based on the power received from the power source.

In another embodiment, the system comprises a controller and a converter configured to receive a first voltage from a power source and step down the first voltage to a lower, secondary voltage, the secondary voltage being indicative of the operating level of the vehicle. The system also includes at least one auxiliary inverter electrically connected to the converter and the auxiliary device, wherein the auxiliary inverter receives secondary voltage. The system also includes a first communication line between the controller and the auxiliary inverter and a second communication line between the controller and the inverter. During operation, if one of the communication lines is interrupted, the auxiliary device

- 1 041633 will continue to operate at a level adequate to the mode of operation of the vehicle, based on the secondary voltage.

In another embodiment, the method includes selecting a secondary voltage provided by the converter based on the mode of operation of the machine, wherein the machine comprises at least one auxiliary device having an electric motor and supplying secondary voltage to an auxiliary inverter electrically connected to the auxiliary device. The method also includes the operation of the auxiliary device at a level adequate to the mode of operation of the machine in case the communication line between the controller and the auxiliary inverter is interrupted or the communication line between the controller and the converter is interrupted.

Brief description of the drawings

The present invention will be described in detail in the following description of non-limiting embodiments with reference to the accompanying drawings.

Fig. 1 is a simplified block diagram of a motorized accessory control system according to an embodiment of the present invention.

Fig. 2 is a simplified block diagram of a secondary link system in accordance with an embodiment of the present invention.

Detailed description of the invention

Below will be detailed embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers used throughout the drawings refer to the same or like elements. While embodiments of the invention are suitable for use with both mobile and fixed implementations, for ease of explanation, the mobile implementation is described in detail herein. In particular, OHV (off-road vehicle) was chosen for clarity of illustration and for disclosure of mobile embodiments.

Other suitable vehicles include road vehicles, off-road vehicles, mining equipment, construction equipment, industrial equipment, and marine vessels. In addition, embodiments of the present invention are equally applicable to any type of machine, moving or non-moving, which contains ancillary elements requiring cooling, such as related power electronics.

Embodiments of the present invention can also be applied to zero emission vehicles, i.e. those that do not reduce the availability of breathable air nearby, as well as hybrid vehicles, i.e. vehicles equipped as a storage device secondary energy, and a device for the production of primary chemical energy, such as a diesel internal combustion engine.

Embodiments of the present invention enable the accessory to operate at a speed or level appropriate to the mode of operation of the machine. As used herein, adequate refers to a condition or condition that is proportional/comparable to, suitable for, or otherwise desirable in relation to the mode of operation of the machine.

Turning now to FIG. 1, embodiments of the invention are configured for use with a moving machine, such as an OHV. In these embodiments, the system typically comprises a primary DC link 10 and a secondary DC link 20. Links 10, 20 are electrically connected to a converter 110, such as a direct current (DC/DC) converter, which steps down the voltage from the primary link to the secondary link. As shown, the primary link 10 is connected to a power source 40, such as an alternator, which powers the system. The alternator may in turn be operatively connected to an internal combustion engine such as a diesel engine. In other embodiments, power source 40 need not be an alternator mechanically coupled to an internal combustion engine, but may be zero emission electrical system components.

The primary link 10 includes a plurality of traction inverters 50 that are connected to a plurality of traction motors 60 and a brake chopper 70. As will be appreciated, the primary link 10 is used to control a machine such as an OHV in which the system is installed. For example, primary link 10 may be used to drive, idle, or brake/decelerate said OHV via traction motors 60. As shown, the system also includes a secondary link 20. Secondary link 20 also includes a plurality of auxiliary inverters 200 that are connected with accessories 210, such as motors. In an OHV embodiment, accessories 210 may include 30-50 hp motors that drive blowers, such as mains, wheel motor blowers, and a control unit, needed to cool the vehicle. In other embodiments, the accessory devices 210 may be driven by more powerful

- 2 041633 engines, for example 100-200 hp The secondary may also include an energy storage device such as a battery 90.

As mentioned, the DC/DC converter 110 steps down the voltage from the primary to the secondary. In an embodiment, converter 110 steps down the voltage from the high voltage traction AC primary DC link to the medium voltage secondary DC link for use by auxiliary devices. The AC medium voltage link provides bus-level voltage and voltage for auxiliary devices such as cooling fans. As will be readily understood, the components within the links electrically interact through standard electrical connectors such as cables.

In one aspect, the voltage is stepped down from the first voltage V1 (eg, high voltage) to the secondary voltage V2 (eg, mid-level voltage). The secondary voltage V2 indicates the operating mode of the OHV. For example, V2 may represent an operating mode of the vehicle such as idling, driving mode, or braking mode. The power (eg voltage) required for each mode is different. For example, for driving, V2 is likely to be higher than for idle. In other words, a higher V2 represents a mode of operation of the vehicle, such as a driving mode, in which a greater amount of system cooling may be required compared to a lower V2, indicating, for example, an idle mode. As used herein, operational mode refers to machine operating conditions or modes, such as the vehicle modes mentioned above, for which appropriate accessory operating modes, such as cooling blower speeds, are necessary or otherwise desirable.

In an embodiment, the first voltage V1 is in the range of about 500 V to about 2200 V and the secondary voltage V2 is in the range of about 580 V to about 860 V. However, as will be appreciated, other levels of the first and secondary voltages may be used in depending on the type of machine / vehicle that is supposed to be used, etc. In some embodiments, it is also possible to use other power values to represent the mode of operation of the vehicle or machine.

Referring now to FIG. 2, system embodiments also include a controller 100 that communicates with a DC/DC converter 110 that includes two H-bridges. In particular, converter 110 includes a primary H-bridge 120 electrically coupled to a transformer 130, which in turn is electrically coupled to a secondary H-bridge 140.

The controller 100 communicates with the inverter 110 via the first link 150 and with the auxiliary inverters 80 via the second link 160. In an embodiment, the communication lines are operatively connected to the inverters and the converter via the controllers of the inverters and converters, respectively (not shown). The controller 100 also communicates with and controls the alternator and hence the primary link 10 via a third link (not shown). In embodiments, the links may be Ethernet or fiber based, although other communication protocols may be used. Although the embodiments are designed to be used with systems containing two/three communication lines, other embodiments may be suitable for use with more than three communication lines between the controller and system components.

As will be appreciated, in addition to communication lines 150, 160, power is transferred between system components. In an embodiment, single-phase AC power 190 is passed between the components (H-bridges 120, 140 and transformer 130) in converter 110. DC power 180 is diverted from the secondary H-bridge to auxiliary inverters. Auxiliary inverters 80 in turn supply single-phase AC power 182 to auxiliary/blower motor 200 210.

In embodiments, system components may be physically located at different locations in a machine, such as a vehicle. For example, in an OHV, the system controller 100 and inverter components may be located in the main housing, and the auxiliary inverters 80 may be located inside the cooling blower inverter housing.

During normal operation, the controller 100 determines and sets the operation mode of the auxiliary device, such as the speed of the blower fan, over the communication lines. That is, the controller 100 receives the vehicle operation mode input, and then the controller controls the blower via a link to the converter 110, ie, the first link 150 and/or the second link 160 to the inverters. In some circumstances, however, it may be possible for the first and/or second communication lines between controller 110 and the converter or inverters to break/interrupt or otherwise fail such that the lines cannot transmit a signal between interconnected components.

In an embodiment of the invention, in the event of a communication line failure, the reduced secondary voltage V2 is used as the communication medium for the cooling blowers or other auxiliary device. That is, the controller 100 schedules the secondary voltage V2 based on the required operation level of the accessory, and the inverters for the accessory are programmed to go to specific speeds based on the secondary voltage V2. For example, if the vehicle is in driving mode, the secondary voltage V2 may be at its rated operating voltage, eg 800 V. The speed of the accessory may be set such that the blower operates at its maximum speed while driving. For a vehicle idle, the accessory speed for that vehicle may be set such that the blower fan operates at a reduced speed corresponding to the vehicle at idle, for example 500V. As will be appreciated, the number of speeds/voltage levels of the accessory may vary depending on the type of vehicle or machine, operating conditions, etc.

In the event that the communication line 160 to the auxiliary inverters is lost, the system controller 100 is unable to control the speed of the blower and does not receive speed or current feedback. Under these conditions, the auxiliary inverters will use the secondary voltage V2 to determine their operating mode.

In the event that the first link 150 to converter 110 is lost, the converter will adjust the secondary voltage to V2. If the second link 160 to the auxiliary inverters is healthy, the inverters can be driven to any level and all the feedback necessary to determine the operating status of the systems will be available. In an embodiment, converter 110 will automatically turn off when it detects an input voltage below a certain threshold, indicating a normal shutdown of the system or abnormal operation of the traction link.

If both links 150, 160 to the controller are broken, then the system defaults to a high mode of operation, such as rated system voltage, until sufficient communication is re-established. For example, in the context of OHV, the system defaults to drive mode, in which ancillary devices (such as blowers) operate at a high level, regardless of whether the vehicle is in drive mode, to prevent potential overheating.

In an embodiment, the vehicle comprises a power source, a controller, a converter configured to receive a first voltage from the power source and convert the first voltage into a second voltage, an auxiliary inverter system electrically connected to the output of the converter, and an auxiliary device having a motor, wherein the auxiliary inverter system configured to convert the second voltage received from the converter to power the electric motor, and the first communication line between the controller and the auxiliary inverter system. The auxiliary inverter system is also configured to control the speed of the motor based on the level of the second voltage in response to the interruption of the first communication line. The vehicle also contains at least one traction inverter electrically connected to the power source, wherein at least one traction motor is electrically connected to the traction inverter and the controller controls the power source as well as the auxiliary inverter. The DC/DC converter contains primary and secondary H-bridge circuits electrically connected to the transformer. In embodiments, the auxiliary device is a blower. The system includes a plurality of auxiliary inverters and may also include an energy storage device electrically coupled to the inverter. The power source is an alternator. Communication lines can use the Ethernet protocol (local area networking standard). The first voltage is in the range of about 500 to about 2200 volts and the secondary voltage is in the range of about 580 to about 860 volts.

In another embodiment, the system includes a controller configured to receive information regarding the mode of operation of the machine, and an accessory device configured to operate in a state that is adequate to the mode of operation of the machine, while the accessory device receives power from a power source. The system also contains at least one communication line between the controller and an auxiliary device, while said line instructs the auxiliary device to operate in a state adequate to the mode of operation of the machine. If the at least one communication line is broken, the auxiliary device can still operate in a state adequate to the mode of operation of the machine, based on the power level received from the power source. In embodiments, the machine is a vehicle and the accessory is a blower. The system also contains an energy storage device connected to the converter, and the power source is an alternator. Communication lines use the Ethernet protocol. Mode

- 4 041633 operation of the vehicle is the driving mode, idling mode and braking mode.

In another embodiment, the system comprises a controller and a converter configured to receive a first voltage from a power source and lower the first voltage to a lower, secondary voltage, the secondary voltage indicating the mode of operation of the machine. The system also includes at least one auxiliary inverter electrically connected to the converter and the auxiliary device, wherein the auxiliary inverter receives secondary voltage. The system also includes a first communication line between the controller and the auxiliary inverter and a second communication line between the controller and the inverter. During operation, if one of the communication lines is interrupted, the auxiliary device will continue to operate at a level adequate to the operating level of the machine, based on the secondary voltage. The system also contains at least one traction inverter electrically connected to the power source, wherein at least one traction motor is electrically connected to the traction inverter, and the controller controls the power source as well as the auxiliary inverter. Converter 110 is a DC/DC converter that includes first and secondary H-bridge circuits electrically coupled to a transformer. In embodiments, the system comprises a plurality of auxiliary inverters. The power source is an alternator. In embodiments, the first voltage is in the range of about 500 V to about 2200 V. The secondary voltage is in the range of about 580 V to about 860 V. In embodiments, the machine is OHV and the OHV mode is drive mode, idle mode, and braking.

In another embodiment, the method includes selecting a secondary voltage generated by the converter based on the operating mode of the machine, wherein the machine comprises at least one auxiliary device having an electric motor, and supplying the secondary voltage to an auxiliary inverter electrically connected to the auxiliary device. The method also includes the operation of the auxiliary device at a level adequate to the mode of operation of the machine, if the communication line between the controller and the auxiliary inverter is interrupted or the communication line between the controller and the converter is interrupted.

It should be understood that the above description is intended to be illustrative and not limiting. For example, the embodiments described above (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention within the scope of the invention. While the dimensions and types of materials described herein are intended to define the parameters of the invention, they are by no means limiting and only represent exemplary embodiments. Many other embodiments are apparent to those skilled in the art upon consideration of the above description. The scope of the invention must therefore be determined with reference to the appended claims, along with the full scope of the equivalents to which said claims fall. In the appended claims, the terms containing and in which are used as equivalents to the terms covering and where. In addition, in the following claims, terms such as first, second, top, bottom, bottom, top, etc. are used simply as designators and are not intended to impose numeric or positional requirements on their entities.

The present description uses examples to disclose some embodiments of the invention, including the best method, and also enables a person skilled in the art to practice embodiments of the invention, including the manufacture and use of any devices or systems and the implementation of the methods involved. The scope of the invention is defined by the claims and may include other examples that can be obtained by a person skilled in the art. Such other examples will be within the scope of the claims if they have structural elements that do not differ from the literal statement of the claims or if they contain equivalent structural elements with minor deviations from the literal statement of the claims.

In the context of this document, an element or step used in the singular is to be understood as not excluding the plural of said elements or steps, unless such an exception is explicitly stated. Furthermore, references to one embodiment of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also include the listed features. Moreover, unless explicitly stated otherwise, embodiments containing, including, or having an element or a plurality of elements having a particular property may include additional such elements that do not have the said property.

Since certain changes can be made to the above power converter and method without departing from the spirit and scope of the invention contained herein, it is intended that everything in the subject matter set forth in the foregoing description or shown in the accompanying drawings is to be construed as examples only. illustrating the concept

- 5 041633 of the invention, and should not be construed as a limitation of the invention.

Claims (12)

CLAIM 1. A method for controlling an auxiliary device with an electric motor in a machine, including receiving a first voltage from a power source and converting the first voltage into a secondary voltage using a converter; converting the secondary voltage received from the inverter with the auxiliary inverter to power the motor of the auxiliary device, the auxiliary inverter being capable of controlling the speed of the motor based on the level of the secondary voltage; controlling the speed of the motor of the auxiliary device in accordance with the operation mode of the machine by the controller by controlling the inverter through the first communication line between the controller and the auxiliary inverter; in response to the interruption of the first communication line, the controller selects the secondary voltage generated by the converter based on the operating mode of the machine through the second communication line between the controller and the converter. 2. The method of claim 1, further comprising converting the first voltage by means of a converter to a secondary voltage, wherein the first voltage is provided by a power supply and the first voltage is higher than the secondary voltage. 3. The method of claim 2, wherein the machine is a vehicle and the power source is the vehicle's alternator. 4. The method of claim 3, wherein the machine is an off-highway vehicle (OHV) and the OHV operating mode is either drive mode, idle mode, or braking mode. 5. The method of claim 2, wherein the first voltage is in the range of about 500 to about 2200 volts. 6. The method of claim 1 wherein the secondary voltage is in the range of about 580 to about 860 volts. 7. The method of claim 1 wherein the converter is a direct current (DC/DC) converter. 8. The method of claim 7, wherein the DC/DC converter comprises primary and secondary H-bridge circuits electrically coupled to the transformer. 9. The method of claim 8, further comprising diverting DC power from the secondary H-bridge circuit to the auxiliary inverter. 10. The method of claim 9, further comprising diverting single-phase AC power from the auxiliary inverter to at least one auxiliary device. 11. The method of claim 1, wherein at least one accessory is a blower. 12. The method of claim 1, wherein the communication links use the Ethernet protocol.