Variable speed drive
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 converter stage connected to an AC power source providing the input AC voltage, the converter stage being configured to convert the input AC voltage to a boosted DC voltage;
a DC link connected to the converter stage, the DC link being configured to filter and store the boosted DC voltage from the converter stage;
an inverter stage connected to the DC link, the inverter stage being configured to convert the boosted DC voltage from the DC link into the output AC power having the variable voltage and the variable frequency; and
an input filter;
the input filter comprising;
a three-phase inductor having three windings, wherein each winding of the three-phase inductor having a center tap dividing each winding into a pair of inductor sections; and
a three-phase input capacitor bank having three capacitors connected in a wye configuration to the three center taps at one end, and to a common point at the opposite end;
wherein the three-phase input capacitor bank is configured to substantially provide a short circuit for frequencies above a predetermined fundamental frequency for shunting frequencies above a predetermined fundamental frequency through the three phase capacitor bank, while passing the predetermined fundamental frequency to the converter stage.
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Accused Products
Abstract
Systems and methods for improved Variable Speed Drives are provided. One embodiment relates to apparatus for common mode and differential mode filtering for motor or compressor bearing protection when operating with Variable Speed Drives, 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. Another embodiment relates to a liquid- or refrigerant-cooled inductor. The liquid- or refrigerant-cooled inductor may be used in any application where liquid or refrigerant cooling is available and a reduction in size and weight of a magnetic component is desired.
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Citations
20 Claims
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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:
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a converter stage connected to an AC power source providing the input AC voltage, the converter stage being configured to convert the input AC voltage to a boosted DC voltage; a DC link connected to the converter stage, the DC link being configured to filter and store the boosted DC voltage from the converter stage; an inverter stage connected to the DC link, the inverter stage being configured to convert the boosted DC voltage from the DC link into the output AC power having the variable voltage and the variable frequency; and an input filter;
the input filter comprising;a three-phase inductor having three windings, wherein each winding of the three-phase inductor having a center tap dividing each winding into a pair of inductor sections; and a three-phase input capacitor bank having three capacitors connected in a wye configuration to the three center taps at one end, and to a common point at the opposite end; wherein the three-phase input capacitor bank is configured to substantially provide a short circuit for frequencies above a predetermined fundamental frequency for shunting frequencies above a predetermined fundamental frequency through the three phase capacitor bank, while passing the predetermined fundamental frequency to the converter stage. - View Dependent Claims (4, 5)
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2. The variable speed drive system of claim 2, further comprising:
- the common point at the opposite end of three-phase input capacitor bank also having a connection to earth ground.
- View Dependent Claims (3, 20)
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6. A variable speed drive system configured to receive an input AC voltage at a fixed AC input voltage and provide an output AC power at a variable voltage and variable frequency, the variable speed drive comprising:
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a converter stage connected to an AC power source providing the input AC voltage, the converter stage being configured to convert the input AC voltage to a boosted DC voltage; a DC link connected to the converter stage, the DC link being configured to filter and store the boosted DC voltage from the converter stage; and an inverter stage connected to the DC link, the inverter stage being configured to convert the boosted DC voltage from the DC link into the output AC power having the variable voltage and the variable frequency; and a phase angle control circuit comprising; a squaring amplifier, a first phase-lock loop circuit associated and a second phase-lock loop circuit; the squaring amplifier configured to receive the AC power source and output a a substantially rectangular output signal based on the AC power source; the first phase-lock loop circuit including a first lag-lead filter configure to have a high filter cutoff frequency and a first capacitor to provides the converter stage with a phase angle parameter; and the second phase-lock loop circuit including a second lag-lead filter configured to have a low cutoff frequency and a second capacitor to provide the lag-lead filter the capability of storing an angle of the mains voltage in the feedback loop of the PLL during mains interruption.
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7. A plastic cooling system for cooling electronic components comprising:
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a base having a top surface onto which at least one electronic component is to be placed; a cooling well formed in the top of the base and open at the top; a feed channel formed in the base for accepting a cooling fluid to be introduced to the cooling well; a drain channel formed in the base through which the cooling fluid is to be carried away from the cooling well; a cooling well inlet formed in the cooling well and in communication with the feed channel; a cooling well outlet formed in the cooling well opposite the cooling well inlet and in communication with the drain channel; and wherein the feed channel is sufficiently large relative to the size and flow characteristics of the well and cooling well inlets and outlets such that when the cooling fluid flows through the cooling device, the pressure drop across the feed channel is substantially less than the pressure drop across the well and wherein the plastic cooling device is a plastic material.
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8. 1. A variable speed drive system (VSD) configured to receive an input AC voltage at a fixed AC input voltage and frequency, and provide an output AC power at a variable voltage and variable frequency, the variable speed drive comprising:
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a converter stage connected to an AC power source providing the input AC voltage, the converter stage being configured to convert the input AC voltage to a boosted DC voltage; a DC link connected to the converter stage, the DC link being configured to filter and store the boosted DC voltage from the converter stage; and an inverter stage connected to the DC link, the inverter stage being configured to convert the boosted DC voltage from the DC link into the output AC power having the variable voltage and the variable frequency; and an integral bypass contactor connected in parallel with the VSD between the AC power source and the AC output power, the integral bypass connector configured to bypass the VSD when the VSD output frequency and voltage are approximately equal with the AC input voltage and frequency. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A variable speed drive system configured to receive an input AC voltage at a fixed AC input voltage and provide an output AC power at a variable voltage and variable frequency, the variable speed drive comprising:
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a converter stage connected to an AC power source providing the input AC voltage, the converter stage being configured to convert the input AC voltage to a boosted DC voltage; a DC link connected to the converter stage, the DC link being configured to filter and store the boosted DC voltage from the converter stage; an inverter stage connected to the DC link, the inverter stage being configured to convert the boosted DC voltage from the DC link into the output AC power having the variable voltage and the variable frequency; a ground fault protection circuit for interrupting fault current flowing to an input phase of the active converter, the ground fault protection circuit including at least one current sensor for sensing a ground fault on the input of the active converter; and a controller; wherein the active converter further includes at least two semiconductor switches for each power phase of the AC power source. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification