AC-DC conversion device and method for controlling same by controlling the timing of multiple switch portions

Patent metadata

Field	Value
Publication number	US-10404157-B2
Application number	US-201615777958-A
Country	US
Kind code	B2
Filing date	Jan 7, 2016
Priority date	Jan 7, 2016
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

An AC-DC conversion device that includes a major circuit portion and a control circuit is provided. The major circuit portion includes a converter in which multiple switch portions in a bridge connection include separately-excited switching elements and snubber circuits connected in parallel with the switching elements; and the major circuit portion is connected to an alternating current power supply and a direct current circuit and applies, to the direct current circuit, an alternating current voltage applied from the alternating current power supply by an ON of the multiple switch portions. The control circuit controls the voltage applied to the direct current circuit by controlling the ON timing of the multiple switch portions by inputting a control pulse to each of the multiple switch portions.

First claim

The invention claimed is:

1. An AC-DC conversion device, comprising:
a major circuit portion including a converter and being connected to an alternating current power supply and a direct current circuit, the converter including a plurality of switch portions having a bridge connection, each of the plurality of the switch portions including a switching element and a snubber circuit, the switching element being separately-excited, the snubber circuit being connected in parallel with the switching element, the major circuit portion applying an alternating current voltage to the direct current circuit by an ON of the plurality of switch portions, the alternating current voltage being applied from the alternating current power supply; and
a control circuit controlling a voltage applied from the converter to the direct current circuit by switching an ON timing of the plurality of switch portions by inputting a control pulse to each of the plurality of switch portions,
the control circuit reducing a control angle of the control pulse input to each of the plurality of switch portions in a range between 90° and 180° when charging a capacitance component included in the direct current circuit to a voltage command value, the control circuit including a voltage estimation circuit estimating a voltage applied to two ends of one of the plurality of switch portions to be triggered when triggering the plurality of switch portions, and the control circuit correcting a rate of the decrease of the control angle based on an estimated value of the voltage estimation circuit to cause the estimated value to be a prescribed value.

2. The AC-DC conversion device according to claim 1 , wherein the control circuit reduces the control angle to cause an increase rate of the voltage applied to the direct current circuit by the converter to be faster than an increase rate of a direct current voltage of the capacitance of the direct current circuit.

3. The AC-DC conversion device according to claim 2 , wherein the control circuit increases the control angle in the 180° direction at a rate slower than a discharging time constant of the direct current circuit in the case where the direct current voltage is higher than the voltage command value.

4. The AC-DC conversion device according to claim 1 , wherein the control circuit performs a protection operation for protecting the plurality of switch portions in the case where the control angle does not advance past an abnormality detection level for a constant interval.

5. The AC-DC conversion device according to claim 1 , wherein the voltage estimation circuit estimates the voltage from the formula
V A-K =k ( V acpeak ×sin α−(¼) V dc),

where V A-K is a voltage applied when triggering the plurality of switch portions,
V acpeak is a peak value of the alternating current voltage of the alternating current power supply,
Vdc is a direct current voltage of the capacitance of the direct current circuit,
α is the control angle, and
k is a prescribed constant.

6. The AC-DC conversion device according to claim 1 , wherein
a command value of a voltage applied to two ends of one of the plurality of switch portions to be triggered when triggering the plurality of switch portions is input to the control circuit, and
the control circuit calculates the control angle according to the command value of the voltage applied to the plurality of switch portions when triggering.

7. The AC-DC conversion device according to claim 1 , wherein
the major circuit portion further includes a current sensor sensing a direct current output from the converter, and
the control circuit corrects a rate of the decrease of the control angle based on a sensed value of the current sensor to cause the direct current to be constant.

8. The AC-DC conversion device according to claim 1 , wherein the control circuit performs the input of the control pulse to the plurality of switch portions in the case where a direct current voltage of the capacitance of the direct current circuit is less than a command value, and does not perform the input of the control pulse to the plurality of switch portions in the case where the direct current voltage of the capacitance of the direct current circuit is not less than the command value.

9. The AC-DC conversion device according to claim 8 , wherein the control circuit performs, each time a prescribed interval elapses, a determination of whether or not the direct current voltage of the capacitance of the direct current circuit is not less than the command value.

10. The AC-DC conversion device according to claim 1 , wherein the control circuit inputs the control pulse to only a designated phase for the plurality of switch portions.

11. The AC-DC conversion device according to claim 1 , wherein
the major circuit portion includes a plurality of voltage sensors sensing voltages applied respectively to the plurality of switch portions, and
the control circuit senses an application of a reverse voltage to the plurality of switch portions based on a signal from the plurality of voltage sensors, and performs a protection operation for protecting the plurality of switch portions in the case where the reverse voltage is not sensed in a 120° conduction interval of one of the plurality of switch portions.

12. The AC-DC conversion device according to claim 1 , wherein
the major circuit portion further includes a current sensor sensing an alternating current of the alternating current power supply, and
the control circuit senses a conduction width of the alternating current based on a sensed value of the current sensor, and performs a protection operation for protecting the plurality of switch portions in the case where the conduction width is a threshold or more.

13. The AC-DC conversion device according to claim 1 , wherein
the major circuit portion further includes a current sensor sensing a direct current output from the converter, and
the control circuit performs a protection operation for protecting the plurality of switch portions in the case where the direct current is flowing continuously.

14. The AC-DC conversion device according to claim 1 , wherein
the major circuit portion further includes a current sensor sensing an alternating current of the alternating current power supply, and
the control circuit performs a protection operation for protecting the plurality of switch portions in the case where an interval in which the alternating current is flowing has continued a prescribed amount of time.

15. An AC-DC conversion device, comprising:
a major circuit portion including a converter and being connected to an alternating current power supply and a direct current circuit, the converter including a plurality of switch portions having a bridge connection, each of the plurality of the switch portions including a switching element and a snubber circuit, the switching element being separately-excited, the snubber circuit being connected in parallel with the switching element, the major circuit portion applying an alternating current voltage to the direct current circuit by an ON of the plurality of switch portions, the alternating current voltage being applied from the alternating current power supply; and
a control circuit controlling a voltage applied from the converter to the direct current circuit by switching an ON timing of the plurality of switch portions by inputting a control pulse to each of the plurality of switch portions,
the control circuit reducing a control angle of the control pulse input to each of the plurality of switch portions in a range between 90° and 180° when c

Assignees

• Toshiba Mitsubishi Elec Ind

Inventors

• Hattori Keisuke
• Yoshino Teruo
• Okami Tomohisa

Classifications

• H02M7/162

  in a bridge configuration · CPC title

• H02M7/155

  using semiconductor devices only · CPC title

• H02M1/34 Primary

  Snubber circuits · CPC title

• H02M7/1626

  with automatic control of the output voltage or current · CPC title

• H02M7/19

  arranged for operation in series, e.g. for voltage multiplication · CPC title