Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
  • H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
  • H02P23/06—Controlling the motor in four quadrants

Definitions

• the present invention relates to inverters, which, connected between the terminals of a direct current source, make it possible to generate alternating current at variable frequency and are intended in particular for controlling the speed of rotation of a rotary electric machine of the asynchronous type and, more specifically, an energy recovery device for such an inverter
• inverters with energy recovery have been described for example in French patents 1,552,477 and 2,315,193, but they have the drawback of be complex and costly to produce compared to the savings.
• the present invention relates to an energy recovery device whose price is low compared to the savings achieved.
• the inverter includes a capacitor connected between the direct current lines, and receiving the energy stored by the leakage inductances of the machine controlled by the inverter, at each switching of a transistor.
• a branch comprising a dissipation resistor for this energy in series with a thyristor, the ignition of which is controlled by the logic already controlling the switching of the other switchable components, is arranged in parallel with the capacitor.
• the energy recovery device essentially consists of a transformer whose primary winding, in series at least with / a switching transistor controlled by logic, is connected between the terminals of the capacitor and whose l The secondary winding is arranged in series between one of the terminals of the DC voltage source and the corresponding input of the inverter.
• This device can be supplemented by several others branches making it possible to improve the operation thereof and to avoid the creation of any overvoltage between the terminals of the transistor used.
• FIG. 1 represents the electrical diagram of an assembly constituted by the inverter and the energy recovery device according to a first embodiment of the present invention.
• FIG. 2 represents the electrical diagram of the same assembly in accordance with a second embodiment of the invention
• FIG. 3 represents the diagram of FIG. 1 to which certain branches have been added to the recovery device to improve its operation.
• the inverter comprises six transistors 1 between which the machine 3 is connected in a known manner.
• the inverter is connected to the output terminals of a direct current generator 4 which generally consists of a controlled rectifier arranged in series with an inductor, at the terminals of an alternating voltage source.
• a logic 5 controls the switching of the transistors 1 of the inverter.
• the device for recovering this energy essentially includes a transformer whose primary winding 13 is arranged in series with at least one switching transistor 14 and whose secondary winding 15 is arranged between one of the terminals of the source of direct current and. the corresponding input of the inverter.
• the energy stored in the capacitor 12 as soon as a voltage appears across its terminals is thus transferred to a current generator placed in series with the current source 4.
• Two diodes 16 and 17 isolate the winding 15 from the current source 4, when the transistor 14 is blocked and there is no energy recovery.
• the diagram shown in FIG. 2 implements two switching transistors 14 and 24.
• the primary winding 13 of the transformer is arranged between the common points, on the one hand, of the transistor 14 and the diode 23 connected in series in a branch connected between the terminals of the capacitor 12 and, on the other hand, of the transistor 24 and diode 25 connected in series in a second identically connected branch.
• the energy is recovered when the two transistors 14 and 24 are conductive and, conversely, the transformer is desaturated by means of the two diodes 23 and 25 when these two same transistors are blocked.
• This diagram has the advantage compared to the device shown in Figure 1 to use transistors whose performance is reduced, therefore less expensive transistors. Indeed, they support a voltage equal to the value of the peak voltage of the capacitor 12 instead of a double voltage of the latter.
• FIG. 3 on which the components common to the diagram of FIG. 1 bear the same references, it can be seen that two branches have been added to the energy recovery device.
• the first of these branches comprises a second secondary winding 18 of the same transformer, in series with a diode 19, the branch being connected in parallel with the capacitor 12.
• This branch has the function of desaturing the transformer when the transistor 1 4 is blocked. It thus allows the magnetizing current to be evacuated automatically and quickly.
• the second of these branches comprises a resistor 20 in series with a thyristor 22 controlled by the logic 5.
• This second branch is connected in parallel with the primary winding 13 of the transformer. Its main purpose is to very quickly decrease the voltage across the transistor 14 when the latter is off, so as to obtain an excellent duration factor and dissipate the energy stored in the primary winding 13 in the resistor 20.
• the direct voltage was approximately 700 V and the operating frequency of the device was 2 kHz for a 30 kW machine. Under these conditions, the device saved approximately 10% of the energy consumed.
• the secondary winding 15 can be arranged in series between the other terminal of the direct current source 4 and the corresponding input of the inverter.
• the recovery device which has just been described can also be implemented with a thyristor inverter and not a transistor.
• the motor connected to the terminals of the inverter can be as well of the asynchronous type as of the under-excited synchronous type.

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Inverter Devices (AREA)
• Control Of Ac Motors In General (AREA)
• Stopping Of Electric Motors (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9233178

Family Applications (1)

Country Status (9)

Cited By (2)

Families Citing this family (4)

Citations (5)

Family Cites Families (2)

• 1979
  • 1979-12-27 FR FR7931734A patent/FR2472871A1/fr active Granted
• 1980
  • 1980-11-20 IE IE241080A patent/IE51256B1/en unknown
  • 1980-12-16 ES ES497781A patent/ES497781A0/es active Granted
  • 1980-12-24 DE DE8080401868T patent/DE3069955D1/de not_active Expired
  • 1980-12-24 WO PCT/FR1980/000188 patent/WO1981001920A1/fr not_active Ceased
  • 1980-12-24 JP JP50024481A patent/JPS56501865A/ja active Pending
  • 1980-12-24 BR BR8008994A patent/BR8008994A/pt not_active IP Right Cessation
  • 1980-12-24 CH CH560481A patent/CH643695A5/fr not_active IP Right Cessation
  • 1980-12-24 EP EP19800401868 patent/EP0031780B1/fr not_active Expired

Patent Citations (6)

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