Rockwell Automation Technologies Incorporated

Craig R Winterhalter

Zoran Vrankovic

Mark Alan Gries

Gary Leonard Skibinski

Arun K Guru

John Balcerak

Lixiang Wei

Robert H Schmidt

Thomas H Van Groll

Michael S Baran

Patrick E Ozimek

John Robert Figie

Gennadi Sizov

Todd M Oestreich

Rui Zhou

Eric Krieg

Rongjun Huang

Behrooz Mirafzal

Bruce A Behrendt

Gregory D Ziegler

Bok Young Hong

Mark V Nelson

Jeffrey J Pankau

Ye Li

John A Balcerak

A system for distributing DC bus voltage and control power to multiple motors includes a rectifier front end supplying a DC bus voltage and a DC control voltage. Both the DC bus voltage and the DC control voltage are distributed via a common set of conductors. Diodes are operatively connected between the DC control voltage and the common set of conductors. The diodes allow forward conduction of the DC control voltage and distribution of control power to distributed devices when the DC bus voltage is not present. Once the DC bus voltage is present, the diodes block conduction of the DC control voltage. Each of the distributed devices are configured with an internal power supply that is operative to generate an internal control voltage from either the DC control voltage or the DC bus voltage.

Apparatus for distributing DC bus power and control power over common conductors in a distributed DC bus system

A system for distributing DC bus voltage and control power to multiple motors includes a rectifier front end supplying a DC bus voltage and a DC control voltage. Both the DC bus voltage and the DC, control voltage are distributed via a common set of conductors. Diodes are operatively connected between the DC control voltage and the common set of conductors. The diodes allow forward conduction of the DC control voltage and distribution of control power to distributed devices when the DC bus voltage is not present. Once the DC bus voltage is present, the diodes block conduction of the DC control voltage. Each of the distributed devices are configured with an internal power supply that is operative to generate an internal control voltage from either the DC control voltage or the DC bus voltage.

A system to detect a ground fault at the output of an inverter section prior to powering up a motor drive system is disclosed. A low voltage power supply is connected to the DC bus prior to connecting the input power source to the rectifier section. If a ground fault exists, the voltage potential on the DC bus causes conduction through one of the freewheeling diodes connected in parallel to the power switching device on the output of the inverter section. A fault detection circuit generates a signal corresponding to the presence of the low voltage potential when the low voltage is applied to the DC bus. If a ground fault is present at the output of one of the inverter sections, the motor drive system prevents the AC voltage from being applied to the rectifier section.

Method and apparatus for detecting ground faults in inverter outputs on a shared DC bus

A filter for reducing radiated emissions in switching power converters such as a motor drive is disclosed. The switching power converter modulates a DC voltage input to generate a desired AC voltage output. Capacitors are connected in parallel between each output phase and a common connection, which may be a ground connection. The magnitude and layout of the capacitors are selected to minimize current conducted by the capacitors. The capacitors may be surface mount technology located proximate to the switching devices or the capacitors may be incorporated in the circuit board on which the switching devices are mounted. The filter may be applied to any of the switching elements in a motor drive, such as the inverter section, an active rectifier section, or a switched mode power supply.

Method and apparatus for reducing radiated emissions in switching power converters

A method for detecting fault conditions in a motor drive at power up is disclosed. During the power up sequence, input power is applied to the motor drive and the DC bus begins to charge to its normal operating level. Once the DC bus has reached a suitable level and prior to commanding motion of the attached motor, the shunt resistor is connected across the DC bus for a short duration. The amplitude of voltage and current present on the DC bus are measured while the shunt resistor is connected across the DC bus. The measurements are then used to detect fault conditions in the motor drive. The presence of the fault conditions are relayed to an operator. Thus, the motor drive may detect certain fault conditions prior to commanding motion from the drive.

Method and apparatus for motor drive diagnostics

A system configured to reduce the amplitude of reactive current present on a DC bus shared by multiple inverters is disclosed. The start of the switching period for the modulation routines of each inverter is synchronized, and a carrier phase angle is determined for a carrier signal within each of the inverters. The modulation routine of each inverter generates a reactive current on the shared DC bus. By controlling the carrier phase angle for each inverter, the reactive current of a first inverter may be generated at a phase angle that is offset from the phase angle of the reactive current generated by a second inverter. As a result, the reactive current from the first inverter cancels at least a portion of the reactive current from the second inverter, reducing the total reactive current present on the DC bus.

System and method for reducing reactive current on a common DC bus with multiple inverters

A system for connecting motor drives to each other is disclosed that does not require the use of wire or tools. The system includes an adapter plug and bus bar modules that connect to each other at a conductive receptacle of the adapter plug to define a splice joint at the point of connect of the bus bar modules. The bus bar modules may include insulating covers and insulating clips may overlie the splice joints so that the system is substantially devoid of exposed surfaces of its conductive materials.

System for connecting motor drives

A cable clamp assembly includes a bracket and first and second fasteners. The first fastener includes a head, a threaded region, and a neck region. The second fastener includes a head, a lower threaded region, an upper threaded region, a lower neck region, and an upper neck region. The first fastener is captured in a first aperture of the bracket by location of the neck region of the first fastener in the first aperture. The second fastener is captured in a second aperture of the bracket by location of the upper neck region of the second fastener in the second aperture. The cable clamp assembly is captured to a wall by arranging the lower neck region of the second fastener to extend through a bore of the wall such that the upper and lower threaded regions of the second fastener are located on opposite sides of the wall.

Cable clamp assembly with double captive screw

An inverter executing a PWM routine is configured to synchronize the switching periods of the PWM routine to an external signal. The external signal is generated, for example, by another inverter, a converter, or a high level controller. The external signal is preferably generated periodically, and the switching period is resynchronized to the external signal each time the external signal is received. Optionally, either the start time or the midpoint of the switching period may be aligned with external signal. Further, the external signal may be sent to multiple inverters. Preferably, a first portion of the inverters align the start time of their respective switching period to the external signal and a second portion of the inverters align the midpoint of their respective switching period to the external signal.

Method and apparatus for synchronization of pulse width modulation

An air cooled switching unit for a motor drive includes a forced air cooling chamber and a convective cooling chamber separate from the forced air cooling chamber. An exhaust port of the forced cooling chamber is configured to direct exhaust air across an outlet of the convective cooling chamber to induce an increased air flow through the convective cooling chamber thereby increasing the cooling capacity of the convective cooling chamber.

Device and method using induction to improve natural convection cooling

A motor drive system provides for analysis of current flow in the DC bus to identify ground faults and their locations. Low-frequency positive polarity and negative polarity current differences indicate ground faults from the positive DC bus and negative DC bus respectively. High-frequency signals indicate ground faults in the motor windings and connecting leads.

Method and apparatus for detecting a location of ground faults in a motor/motor drive combination

The present invention includes techniques for configuring an electric drive module designed for various multi-axis drive system configurations. Embodiments include techniques for integrating a three phase dual converter with a diode bridge and drive controller within a single drive module. Further integrating the diode bridge directly within the drive module may result in an integrated, modular building block for multiple electric drive system configurations. In some embodiments, multiple electric drive modules are connected by a DC bus to form a system configured for higher energy efficiency.

Configurable multi-axis electric drive system concept

A method for controlling a motor drive system, the system comprising an AC-DC converter coupled to a DC-AC inverter by a DC bus, a motor coupled to and driven by the inverter, and a load coupled to and driven by the motor is provided. The method includes accessing a motion profile for the motor and load and determining power losses of the converter, the inverter, the motor and the load. The method also includes controlling the voltage of the DC bus based upon the motion profile and the power losses to enhance the motor drive system efficiency, reliability and motor shaft performance.

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Cedarburg, WI, United States of America

Craig R Winterhalter