Motor drive architecture for variable frequency alternating current loads

Patent metadata

Field	Value
Publication number	US-10770987-B2
Application number	US-201816028652-A
Country	US
Kind code	B2
Filing date	Jul 6, 2018
Priority date	May 11, 2018
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

A method and system for controlling a three-phase drive connected to a three phase power source. The method includes connecting a converter to transfer power from the power source to a first direct current (DC) bus, where the converter and the first DC bus each have a neutral common point (NCP). Connecting a second DC bus to the first DC bus and configuring an inverter connected to the second DC bus to draw power from the second DC bus to provide a plurality of motor signals, the inverter having an inverter NCP. The method also includes connecting a neutral point selection device to the first DC bus NCP and selectively connecting to the converter NCP or the inverter NCP, the bus selection device configured to disconnect the converter NCP or the inverter NCP from the first DC bus NCP under selected conditions.

First claim

What is claimed is:

1. A three-phase active front-end motor drive system with short circuit protection, the drive system comprising:
a multi-level converter having a converter neutral common point configured to transfer power from a three-phase alternating current (AC) power source to a first direct current (DC) bus, the first direct current bus having a positive terminal, a negative terminal, and a neutral common point;
a second DC bus having a positive terminal and a negative terminal, the second DC bus operably connected to the first DC bus, with the positive terminal of the second DC bus operably connected to the positive terminal of the first DC bus, and the negative terminal of the second DC bus operably connected to the negative terminal of the first DC bus;
an inverter operably connected to the second DC bus, the inverter configured to draw power from the positive terminal of the second DC bus and negative terminal of the second DC bus to provide a plurality of motor excitation signals, the inverter having an inverter neutral common point;
a neutral point selection device operably connected to the first DC bus neutral common point of the first DC bus and selectively connectable to at least one of the converter neutral common point and the inverter neutral common point, the bus selection device configured to disconnect the at least one of the converter neutral common point and the inverter neutral common point from the first DC bus neutral common point under selected conditions; and
an inrush current limiter, wherein the converter is a multilevel converter including the inrush current limiter, the inrush current limiter comprises a bypass diode and a series positive temperature coefficient thermistor selectively shunted by an active switching device.

2. The three-phase active front-end motor drive of claim 1 , further comprising
a controller operably connected to the multi-level converter and the inverter, the controller configured to:
generate control signals to cause the multi-level converter to transfer power to the first DC bus; and
generate control signals to cause the inverter to transfer power from the second DC bus to generate a plurality of motor excitation signals.

3. The three-phase active front-end motor drive of claim 2 , wherein the controller generates a pulse width modulation (PWM) signal with a selected duty cycle for the converter control signals based on at least a current loading of the DC bus.

4. The three-phase active front-end motor drive of claim 2 , wherein the controller generates a pulse width modulation (PWM) signal with a selected duty cycle for the inverter control signals based on at least one of a position of the motor, a speed of the motor, and a load of the motor.

5. The three-phase active front-end motor drive of claim 1 , further including a first bus selection device operably connected to the positive terminal of first DC bus and selectively connectable to the positive terminal of second DC bus, and a second bus selection device operably connected to the negative terminal of first DC bus and selectively connectable to the negative terminal of second DC bus, the first and second bus selection devices configured to disconnect the second DC bus from the first DC bus under selected conditions.

6. The three-phase active front-end motor drive of claim 5 , wherein at least one of the first bus selection device and the second bus selection device is at least one of a fuse, a circuit breaker, a contactor, a passive current interruption device, and an active switching device.

7. The three-phase active front-end motor drive of claim 6 , wherein at least one of the first bus selection device and the second bus selection device is operably connected to a controller, and responsive to a control signal from the controller based on at least a current load of the inverter.

8. The three-phase active front-end motor drive of claim 1 , wherein the neutral point selection device is at least one of a fuse, a circuit breaker, a contactor, a passive current interruption device, and an active switching device.

9. The three-phase active front-end motor drive of claim 8 , wherein the neutral point selection device is operably connected to a controller and responsive to a control signal from a controller based on at least one of a current load of the inverter and input current level.

10. The three-phase active front-end motor drive of claim 1 , wherein the converter is a three level, three phase converter, and the inverter is a two level, three phase inverter.

11. The three-phase active front-end motor drive of claim 1 , wherein at least one of the converter and the inverter, is a three level converter or inverter respectively.

12. The three-phase active front-end motor drive of claim 1 , wherein at least one of the converter and the inverter comprise at least six switching devices.

13. The three-phase active front-end motor drive of claim 1 , wherein the active switching device incudes a thyristor operatively connected to a controller and responsive to a control signal from the controller based on a current in the converter.

14. The three-phase active front-end motor drive of claim 1 , wherein the converter neutral point is not electrically connected to the inverter neutral point.

15. A motor control system with a three-phase active front-end drive including short circuit protection, comprising:
a multi-level converter having a converter neutral common point configured to transfer power from a three-phase alternating current (AC) power source to a first direct current (DC) bus, the first direct current bus having a positive terminal, a negative terminal, and neutral common point;
a second DC bus having a positive terminal and a negative terminal, the second DC bus operably connected to the first DC bus, with the positive terminal of the second DC bus operably connected to the positive terminal of the first DC bus, and the negative terminal of the second DC bus operably connected to the negative terminal of the first DC bus;
an inverter operably connected to a second DC bus; the inverter configured to draw power from the positive terminal of the second DC bus and negative terminal of the second DC bus to provide a plurality of motor excitation signals, the inverter having an inverter neutral common point;
a neutral point selection device operably connected to the first DC bus neutral common point of the first DC bus and selectively connectable to at least one of the converter neutral common point and the inverter neutral common point, the bus selection device configured to disconnect the at least one of the converter neutral common point and the inverter neutral common point from the first DC bus neutral common point under selected conditions;
a motor operably connected to the inverter, the motor configured to receive the plurality of motor excitation signals; and
an inrush current limiter, wherein the multilevel converter includes the inrush current limiter, the inrush current limiter comprises a bypass diode and a series positive temperature coefficient thermistor selectively shunted by an active switching device.

16. The motor control system of claim 15 , further comprising:
a controller operably connected to the multi-level converter as well as the inverter, the controller configured to:
generate control signals to cause the multi-level converter to transfer power to the first DC bus; and
generate control signals to cause the inverter to transfer power from the second DC bus to generate a plurality of motor excitation signals respectively.

17. The

Assignees

• Hamilton Sundstrand Corp
• Hamilton Sunstrand Corp

Inventors

• Kumar Dhananjay
• Somani Vaibhav Kumar

Classifications

• H02P1/16

  for starting dynamo-electric motors or dynamo-electric converters · CPC title

• H02M5/4505

  having a rectifier with controlled elements · CPC title

• H02P27/14

  with three or more levels of voltage · CPC title

• H02H3/025

  Disconnection after limiting, e.g. when limiting is not sufficient or for facilitating disconnection · CPC title

• H02M7/49

  Combination of the output voltage waveforms of a plurality of converters · CPC title