Multi-pulse constant voltage transformer for a variable speed drive in chiller applications
First Claim
1. A variable speed drive system configured to receive an input AC power at a fixed AC input voltage magnitude and frequency and provide an output AC power at a variable voltage and variable frequency, the variable speed drive comprising:
- a multiple pulse transformer, connected to a three-phase AC power source providing the input AC voltage;
a converter configured to convert the input AC voltage to a DC voltage;
a DC link connected to the converter stage, the DC link being configured to filter and store the DC voltage from the converter stage; and
an inverter connected to the DC link, the inverter being configured to convert the DC voltage from the DC link into the output AC power having the variable voltage and the variable frequency;
the multiple pulse transformer comprising;
three primary windings, each of the primary windings connected to a phase of the three-phase AC power source, each of the primary windings comprising a plurality of input terminals, wherein a first input terminal of the plurality of input terminals is wound for a first utility voltage available at the AC power source and a second input terminal of the plurality of input terminals is wound for a second utility voltage available at the AC power source, and wherein the first utility voltage is different than the second utility voltage;
a plurality of secondary windings, each secondary winding comprising three phase windings respectively, each phase winding of the respective secondary winding comprising a predetermined phase shift with respect to a corresponding phase winding of the remaining secondary windings;
wherein the phase shifting of the phase windings results in three sinusoidal output voltage waves for each secondary winding, the sinusoidal output voltage waves being substantially evenly spaced over 360 degrees.
2 Assignments
0 Petitions
Accused Products
Abstract
A multi-pulse transformer with multiple taps provides a constant magnitude voltage output to a variable speed chiller'"'"'s compressor motor over a range of input voltages. The 3-phase transformer includes primary windings and a plurality of secondary windings. The secondary windings are electromagnetically coupled with the associated primary winding. The primary windings include taps for receiving multiple input AC voltages and the secondary windings have a single output terminal for supplying a predetermined output voltage which, after rectification produces a DC multi-pulse waveform for powering a DC link of a variable speed drive. Alternatively the 3-phase transformer includes multiple taps on the secondary windings. Each of the primary windings has a terminal for receiving an input AC voltage. The taps of the secondary windings provide an output voltage that is converted to a multi-pulse waveform for powering a DC link of a variable speed drive.
12 Citations
20 Claims
-
1. A variable speed drive system configured to receive an input AC power at a fixed AC input voltage magnitude and frequency and provide an output AC power at a variable voltage and variable frequency, the variable speed drive comprising:
-
a multiple pulse transformer, connected to a three-phase AC power source providing the input AC voltage; a converter configured to convert the input AC voltage to a DC voltage; a DC link connected to the converter stage, the DC link being configured to filter and store the DC voltage from the converter stage; and an inverter connected to the DC link, the inverter being configured to convert the DC voltage from the DC link into the output AC power having the variable voltage and the variable frequency; the multiple pulse transformer comprising; three primary windings, each of the primary windings connected to a phase of the three-phase AC power source, each of the primary windings comprising a plurality of input terminals, wherein a first input terminal of the plurality of input terminals is wound for a first utility voltage available at the AC power source and a second input terminal of the plurality of input terminals is wound for a second utility voltage available at the AC power source, and wherein the first utility voltage is different than the second utility voltage; a plurality of secondary windings, each secondary winding comprising three phase windings respectively, each phase winding of the respective secondary winding comprising a predetermined phase shift with respect to a corresponding phase winding of the remaining secondary windings; wherein the phase shifting of the phase windings results in three sinusoidal output voltage waves for each secondary winding, the sinusoidal output voltage waves being substantially evenly spaced over 360 degrees. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A variable speed drive system configured to receive an input AC power at a fixed AC input voltage magnitude and frequency and provide an output AC power at a variable voltage and variable frequency, the variable speed drive comprising:
-
a multiple pulse transformer, connected to a three-phase AC power source providing the input AC voltage; a converter configured to convert the input AC voltage to a DC voltage; a DC link connected to the converter stage, the DC link being configured to filter and store the DC voltage from the converter stage; and an inverter connected to the DC link, the inverter being configured to convert the DC voltage from the DC link into the output AC power having the variable voltage and the variable frequency; the multiple pulse transformer comprising; three primary windings, each of the primary windings connected to a phase of the three-phase AC power source, each of the primary windings comprising a plurality of input terminals for connection to the AC power source, wherein a first input terminal of the plurality of input terminals is wound for a first utility voltage available at the AC power source and a second input terminal of the plurality of input terminals is wound for a second utility voltage available at the AC power source, and wherein the first utility voltage is different than the second utility voltage; and a plurality of secondary phase windings, each secondary phase winding having multiple voltage output terminals. - View Dependent Claims (12, 13, 14, 15, 16, 17)
-
-
18. A chiller system comprising:
-
a refrigerant circuit comprising compressor, a condenser, and an evaporator connected in a closed refrigerant loop; and a multiple pulse transformer comprising three primary windings connected to a three-phase AC power source and a plurality of secondary windings connected to a variable speed drive to power a motor of the compressor; each of the primary windings comprising a plurality of input terminals for connection to the three-phase AC power source, wherein a first input terminal of the plurality of input terminals is wound for a first utility voltage available at the three-phase AC power source and a second input terminal of the plurality of input terminals is wound for a second utility voltage available at the three-phase AC power source, and wherein the first utility voltage is different than the second utility voltage; at least one of the secondary windings comprising multiple terminals for providing a multiple phase output voltage comprising a predetermined phase shift with respect to a corresponding winding of the remaining secondary windings; wherein the phase shifting of the multiple phase output voltage provides three multiple sinusoidal output voltage waves for each of the plurality of secondary windings with the multiple sinusoidal output voltage waves being substantially evenly spaced over 360 degrees. - View Dependent Claims (19, 20)
-
Specification