Johnson Controls Technology Company

Shreesha Adiga-Manoor

Ivan Jadric

Michael S Todd

Konstantin A Borisov

Ajit Wasant Kane

Harold Robert Schnetzka

Zhiqiao Wu

A system or method controlling a variable speed drive based on PWM techniques, wherein a first PWM method is used when the input current is less than a predetermined threshold value, for higher efficiency and lower total harmonic distortion (THD); and a second PWM method comprising a discontinuous modulation signal is used when the input current is greater than the predetermined threshold value for higher efficiency. By doing so, the maximum efficiency of VSD within the whole operation range can be achieved.

Hybrid pulse width modulation method for variable speed drive

A converter module for a variable speed drive having a semiconductor device for precharge is described. The precharge circuit includes switching modules, one switching module with a first semiconductor switch connected in parallel or series with a second semiconductor switch. The second semiconductor switch is switched on and off during the precharge operation in order to limit the inrush current into the DC Link. After the precharge operation, the second semiconductor switch is turned on all the time and acts like a diode. The second semiconductor device may have a lower maximum current rating than the main semi-conductor devices. The lower current rated semiconductor device experience the same short circuit current as the higher current rated semiconductor device. The lower current rated semiconductor device can be supplied with a larger gate to emitter voltage than the higher current rated semiconductor device to equalize current between semiconductor devices.

Variable speed drive

A grounding system for a semiconductor module of a variable speed drive includes a first conductive layer, a second conductive layer; a substrate disposed between the first conductive layer and the second conductive layer; and a base attached to the second conductive layer, the base being connected to earth ground via a grounding harness. The first conductive layer is in electrical contact with the semiconductor module and the substrate, and electrically insulated from the second conductive layer by the substrate. The second conductive layer is in electrical contact with the substrate and disposed between the substrate and the base in electrical communication with an earth ground. The first conductive layer, the substrate and the second conductive layer form a capacitance path between the semiconductor module and the base as well as electrical conductors and the base for reduction circulating currents within the semiconductor module.

Grounding system and apparatus

An optocoupler circuit includes a switch connected in parallel with a photo LED, the photo LED having an anode and a cathode. The anode is connected to a power supply via a decoupling capacitor. The optocoupler circuit is arranged so that the switch turns on the photo LED when in the open position. When closed, the switch directs current flow through a series resistor to ground and shunts current flow away from the photo LED to turn off the photo LED. A second capacitor is connected to the cathode of the photo LED. The second capacitor is wired in series with a second switch and a current limiting resistor connected to ground. The first switch and second switch operate in complementary states to prevent the cathode connected capacitor from discharging. The disclosed optocoupler circuit provides the ability to function at increased levels of common mode voltage transients.

Optocoupler circuit for gate driver

Systems and methods for improved VSDs are provided. One embodiment relates to an apparatus for common mode and differential mode filtering for motor or compressor bearing protection when operating with VSDs, including conducted EMI/RFI input power mains mitigation. Another embodiment relates to a method to extend the synchronous operation of an Active Converter to the AC mains voltage during complete line dropout. Another embodiment relates to an Active Converter-based Variable Speed Drive system with Improved Full Speed Efficiency.

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York, PA, United States of America

Shreesha Adiga-Manoor