System for precharging a DC link in a variable speed drive

• US 20060208685A1
• Filed: 12/30/2005
• Published: 09/21/2006
• Est. Priority Date: 03/01/2005
• Status: Active Grant

• Current Assignee: York International Corporation (Johnson Controls International plc)
• Original Assignee: York International Corporation (Johnson Controls International plc)
• Inventors: Schnetzka, Harold R.
• Granted Patent: US 7,619,906 B2
• Time in Patent Office: Days
• US Class Current: 318/800
• CPC Class Codes: H02H 9/001 limiting speed of change of electric quantities, e.g. soft switching on or off progressive control of electronic switches for eliminating interferences H03K17/16
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 5/4585 having a rectifier with controlled elements
• CPC Class Codes: H02M 7/125 Avoiding or suppressing excessive transient voltages or currents
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A variable speed drive with a converter that is controllable to precharge a DC link is provided. The variable speed drive also includes an inverter. The converter converts a fixed line frequency, fixed line voltage AC power from an AC power source into DC power. The DC link filters the DC power from the converter. Finally, the inverter is connected in parallel with the DC link and converts the DC power from the DC link into a variable frequency, variable voltage AC power. The converter includes a plurality of pairs of power switches, wherein each pair of power switches includes a reverse blocking power switch arrangement connected in anti-parallel to another reverse blocking power switch arrangement. Alternatively, each pair of power switches includes a reverse blocking power switch connected in anti-parallel with a silicon carbide controlled rectifier.

Claims

1. A variable speed drive comprising:

an inverter arrangement to convert a DC voltage to an AC voltage to power a load;

a DC link to filter and store energy, the DC link being electrically connected in parallel to the inverter arrangement;

a converter arrangement to convert an AC voltage from an AC power source to a DC voltage, the converter arrangement being electrically connected in parallel to the DC link, the converter arrangement comprising a plurality of pairs of power switch arrangements, wherein each pair of power switch arrangements includes a first reverse blocking power switch configuration connected in anti-parallel to a second reverse blocking power switch configuration; and

wherein the converter arrangement is controllable to precharge the DC link.

2. The variable speed drive of claim 1 wherein the first reverse blocking power switch configuration is a reverse blocking insulated gate bipolar transistor and the second reverse blocking power switch configuration is a reverse blocking insulated gate bipolar transistor.

3. The variable speed drive of claim 1 wherein:

the first reverse blocking power switch configuration is a first insulated gate bipolar transistor connected in series with a first diode configured to provide reverse blocking;

the second reverse blocking power switch configuration is a second insulated gate bipolar transistor connected in series with a second diode configured to provide reverse blocking; and

the first insulated gate bipolar transistor is connected in anti-parallel with the second diode, and the second insulated gate bipolar transistor is connected in anti-parallel with the first diode.

4. The variable speed drive of claim 1 wherein the converter arrangement is controllable by a pulse width modulation technique.

5. The variable speed drive of claim 1 wherein the converter arrangement is configured to operate as a boost rectifier.

6. A chiller system comprising:

a refrigerant circuit comprising a compressor, a condenser arrangement and an evaporator arrangement connected in a closed loop;

a drive arrangement connected to the compressor to power the compressor, the drive arrangement comprising a motor and a variable speed drive, the variable speed drive comprising;

an inverter arrangement electrically connected to the motor, the inverter arrangement being configured to convert a DC voltage to an AC voltage to power the motor;

a DC link to filter and store energy, the DC link being electrically connected in parallel to the inverter arrangement; and

a converter arrangement to convert an AC voltage from an AC power source to a DC voltage, the converter arrangement being electrically connected in parallel to the DC link, the converter arrangement comprising a plurality of pairs of power switch arrangements, wherein each pair of power switch arrangements includes a first reverse blocking power switch configuration connected in anti-parallel to a second reverse blocking power switch configuration; and

wherein the converter arrangement is controllable to precharge the DC link.

7. The chiller system of claim 6 wherein the first reverse blocking power switch configuration is a reverse blocking insulated gate bipolar transistor and the second reverse blocking power switch configuration is a reverse blocking insulated gate bipolar transistor.

8. The chiller system of claim 6 wherein:

the first reverse blocking power switch configuration is a first insulated gate bipolar transistor connected in series with a first diode configured to provide reverse blocking;

the second reverse blocking power switch configuration is a second insulated gate bipolar transistor connected in series with a second diode configured to provide reverse blocking; and

the first insulated gate bipolar transistor is connected in anti-parallel with the second diode, and the second insulated gate bipolar transistor is connected in anti-parallel with the first diode.

9. The chiller system of claim 6 wherein the converter arrangement is controllable by a pulse width modulation technique.

10. The chiller system of claim 6 wherein the converter arrangement is configured to operate as a boost rectifier.

11. A variable speed drive comprising:

an inverter module to convert a DC voltage to an AC voltage to power a load;

a DC link to filter and store energy, the DC link being electrically connected in parallel to the inverter module;

a converter module to convert an AC voltage from an AC power source to a DC voltage, the converter module being electrically connected in parallel to the DC link, the converter module comprising a plurality of pairs of power switches, wherein each pair of power switches includes;

a first insulated gate bipolar transistor in series with a first diode configured to provide reverse blocking;

a second insulated gate bipolar transistor in series with a second diode configured to provide reverse blocking, the second insulated gate bipolar transistor in series with the second diode being connected in anti-parallel with the first insulated gate bipolar transistor in series with the first diode; and

wherein the first insulated gate bipolar transistor being connected in inverse parallel with the second diode, and the second insulated gate bipolar transistor being connected in inverse parallel with the first diode; and

wherein the converter module is controllable to precharge the DC link.

12. The variable speed drive of claim 11 wherein the converter module is controllable by a pulse width modulation technique.

13. The variable speed drive of claim 11 wherein the converter module is configured to operate as a boost rectifier.

14. The variable speed drive of claim 11 wherein the second insulated gate bipolar transistor is controllable to provide pulses of inrush current to the DC link to precharge the DC link.

15. The variable speed drive of claim 14 wherein the second insulated gate bipolar transistor is controllable to conduct at all times in response to completion of the precharge of the DC link.

16. The variable speed drive of claim 11 wherein each pair of power switches includes an insulated gate bipolar transistor connected in anti-parallel to a diode.

17. A chiller system comprising:

a refrigerant circuit comprising a compressor, a condenser arrangement and an evaporator arrangement connected in a closed loop;

a drive arrangement connected to the compressor to power the compressor, the drive arrangement comprising a motor and a variable speed drive, the variable speed drive comprising;

an inverter module electrically connected to the motor, the inverter module being configured to convert a DC voltage to an AC voltage to power the motor;

a DC link to filter and store energy, the DC link being electrically connected in parallel to the inverter module;

a converter module to convert an AC voltage from an AC power source to a DC voltage, the converter module being electrically connected in parallel to the DC link, the converter module comprising a plurality of pairs of power switches, wherein each pair of power switches includes a first insulated gate bipolar transistor and anti-parallel diode connected in series with a second insulated gate bipolar transistor and anti-parallel diode, the second insulated gate bipolar transistor and anti-parallel diode having an inverse configuration with respect to the first insulated gate bipolar transistor and anti-parallel diode; and

wherein the first insulated gate bipolar transistor being connected in series with the anti-parallel diode for the second insulated gate bipolar transistor, and the second insulated gate bipolar transistor being connected in series with the anti-parallel diode for the first insulated gate bipolar transistor; and

wherein the converter module is controllable to precharge the DC link.

18. The chiller system of claim 17 further comprising a control system to control operation of the variable speed drive and wherein the control system is configured to control the second insulated gate bipolar transistor to provide pulses of inrush current to the DC link to precharge the DC link.

19. The chiller system of claim 18 wherein the control system is configured to control the second insulated gate bipolar transistor to conduct at all times in response to completion of the precharge of the DC link.

20. The chiller system of claim 18 wherein the control system is configured to control the converter module by a pulse width modulation technique.

21. The chiller system of claim 17 wherein each pair of power switches includes an insulated gate bipolar transistor connected in anti-parallel to a diode.

22. The chiller system of claim 17 wherein the converter module is configured to operate as a boost rectifier.