JP2006014570A - Power regeneration method and converter device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power regeneration method in which regeneration efficiency can be improved, and a converter device using the same. <P>SOLUTION: In the regeneration of single phase converter K having regenerative transistors Q, the set of transistors Q, Q to be forced into conduction is selected after determining the polarity of a power source E, and a command 31 to allow its conduction is created. On the other hand, a regeneration operation command 32 is created by processing an output voltage Vdc according to a regeneration threshold Vr, and a control signal 33 is created for turning the set of selected transistors Q, Q on/off in accordance with AND (logical product) of both commands 31, 32. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power regeneration method and a converter device using the same. More specifically, the present invention relates to a power regeneration method capable of improving regeneration efficiency and a converter device using the same.

  In general, regenerative braking is performed as a braking method when an electric motor including an induction motor is driven by a so-called inverter. Regenerative braking is a method of obtaining braking force while lowering the output frequency of the inverter and operating the motor as a generator, and is one of the most efficient braking methods.

  FIG. 3 shows an example of a converter device that constitutes a part of such an inverter. This converter device 100 has a single-phase bridge circuit 101 using diodes D11, D12, D13, and D14 and a smoothing capacitor 102, and converts the single-phase alternating current from the power source E ′ into direct current by the bridge circuit 101. The smoothing capacitor 102 repeatedly charges and discharges to output a DC voltage Vdc ′.

  Further, converter device 100 uses regenerative power to release regenerative energy as thermal energy in order to prevent voltage Vdc ′ from being increased by regenerative power and destroying circuit elements when the load is in a regenerative state. A unit 103 is provided.

  The regenerative power consumption unit 103 monitors a regenerative resistor 104 connected in parallel with the smoothing capacitor 102 and consuming regenerative power, a transistor 105 connected in series with the regenerative power, and an output voltage Vdc ′, and has a voltage Vdc ′. When the voltage rises above a certain value, the transistor 105 is turned on, the regenerative resistor 104 is turned on, and the regenerative control circuit 106 controls the regenerative energy to be consumed as heat energy.

  In such a conventional converter device 100, since all the regenerative power is consumed as heat energy by the regenerative resistor 104, there is a problem that the energy cannot be effectively used.

  Further, since all the generated regenerative power is consumed as thermal energy, there is another problem that it is necessary to use a relatively large resistance and it is difficult to reduce the size of the apparatus.

  For this reason, it is conceivable to perform power regeneration using a so-called PWM converter 110 as shown in FIG. However, in the conventional PWM converter, all the regenerative energy including inrush current flows into the power feedback transistors Q11, Q12, Q13, Q14 connected in antiparallel with the rectifying elements D11 to D14. In addition, it is necessary to use a large-capacity sensor or to provide a current sensor to limit the current, which causes a problem that the system becomes complicated, resulting in an increase in cost and an increase in the size of the apparatus.

Japanese Patent Laid-Open No. 2000-156937 proposes a power regeneration device that does not require a discharge circuit.
JP 2000-156937 A

  The present invention has been made in view of the problems of the prior art, and an object thereof is to provide a power regeneration method capable of improving the regeneration efficiency and a converter device using the same.

  The power regeneration method of the present invention is a power regeneration method for a single-phase converter having a regeneration transistor, the procedure for determining the polarity of the power supply, the procedure for detecting the peak value of the power supply voltage, and the procedure for detecting the output voltage. A procedure for selecting a set of transistors to be conducted based on the polarity; a procedure for setting a conduction possible period for the selected transistor set; a procedure for correcting the conduction possible period and generating a conduction possible command; A control signal for turning on / off the selected transistor pair is generated based on a procedure for generating a regenerative operation command by thresholding the output voltage and a logical product of the conduction enable command and the regenerative operation finger. And a procedure.

  In the power regeneration method of the present invention, the conduction possible period is corrected, for example, by giving a dead time to the rising portion.

  In the power regeneration method of the present invention, for example, a signal for turning on the transistor set is generated for a period in which the ON period of the conduction enable command and the ON period of the regenerative operation command overlap. .

  Furthermore, in the power regeneration method of the present invention, it is preferable to change the threshold according to the load fluctuation.

  Furthermore, in the power regeneration method of the present invention, for example, the period during which the output voltage exceeds the threshold is set as the ON period of the regeneration operation command.

  On the other hand, the power regeneration device of the present invention is a power regeneration device of a single phase converter having a regeneration transistor, a polarity determination unit for determining the polarity of the power source, a peak value detection unit for detecting the peak value of the power supply voltage, An output voltage detection unit for detecting an output voltage; and a power regeneration control unit, wherein the power regeneration control unit detects the polarity of the power source determined by the polarity determination unit, the peak value detected by the peak value detection unit, A control signal for controlling on / off of the transistor is generated based on the output voltage detected by the output voltage detector.

  In the power regeneration device of the present invention, the power regeneration control unit, for example, a transistor selection command generation unit that generates a command for selecting a set of transistors based on the polarity of the power source determined by the polarity determination unit, and the transistor selection A conduction possible period setting unit for setting a conduction possible period of a set of transistors selected based on a command from the command generation unit, and a conduction possible signal by correcting the conduction possible period set by the conduction possible period setting unit. A regenerative operation command generating unit that generates a regenerative operation command based on the polarity of the continuity that can be generated, the polarity of the power source determined by the polarity determination unit, the output voltage detected by the voltage detection unit, and the regeneration threshold; The transistor selected by calculating the logical product of the conduction enable command from the conduction enable period correcting unit and the regenerative operation command from the regenerative operation command generating unit. It is made and a control signal generator for generating a control signal for controlling the on and off.

  In the power regeneration device of the present invention, for example, a signal for turning on the transistor set is generated for a period in which the ON period of the conduction enable command and the ON period of the regenerative operation command overlap. It is supposed to be.

  Furthermore, in the power regeneration device of the present invention, for example, the regeneration threshold is changed according to the load fluctuation.

  Furthermore, in the power regeneration device of the present invention, for example, the period during which the output voltage exceeds the regeneration threshold is set as the ON period of the regeneration operation command.

  Furthermore, in the power regeneration device of the present invention, the conduction possible period is corrected, for example, by giving a dead time to the rising portion.

  Furthermore, in the power regeneration device of the present invention, it is preferable that a regenerative power consuming unit is arranged in series on one of the DC buses of the single-phase converter.

  According to the present invention, it is possible to obtain an excellent effect that efficiency in power regeneration is improved while simplifying control.

  Hereinafter, although the present invention is explained based on an embodiment, referring to an accompanying drawing, the present invention is not limited only to this embodiment.

  FIG. 1 shows a converter device using a power regeneration method according to an embodiment of the present invention.

  The converter device K supplies direct current to an inverter device (inverted device in a narrow sense, that is, an inverse conversion device) that performs speed control of an AC motor (not shown). As shown in FIG. The AC motor is connected to a phase AC power source E, rectifies the input AC from the power source E when the AC motor is powered, and outputs it from the DC buses P and N via the output terminals O1 and O2. It is configured as a power regenerative converter to be fed back to

  Specifically, the converter device K includes a rectifying unit 1 that rectifies input alternating current, a smoothing unit 2 that smoothes output direct current, a regenerative power consuming unit 3 that consumes regenerative power during power regeneration, and an AC power supply. A polarity discriminating unit 4 for discriminating the polarity of E, a crest value detecting unit 5 for detecting a crest value Vem of the power supply voltage Ve, a voltage detecting unit 6 for detecting an output DC voltage (hereinafter simply referred to as output voltage) Vdc, A power regeneration control unit 7 that controls power regeneration in the rectifying unit 1 based on the outputs of the polarity discriminating unit 4, the peak value detecting unit 5 and the voltage detecting unit 6 is provided as a main component.

  Here, the power regeneration control unit 7 can conduct with the transistor selection unit 11 that selects the transistor Q to be conducted, and the conduction possible period setting unit 12 that sets the conduction possible period of the transistor Q selected by the transistor selection unit 11. It includes a conduction possible period correction unit 13 that corrects the conduction possible period set by the period setting unit 12 to generate a conduction possible signal, a regenerative operation command generation unit 14, and a control signal generation unit 15. In addition, the electric power regeneration control part 7 which has such each part is implement | achieved by storing the program matched with each function mentioned later, for example in a microcomputer.

  The rectifying unit 1 connects regenerative power feedback transistors Q1, Q2, Q3, and Q4 in antiparallel to each of four rectifying elements (diodes) D1, D2, D3, and D4 that form a single-phase bridge circuit. It is supposed to be.

  The smoothing unit 2 is configured by connecting one terminal of a capacitor 21 having a predetermined capacity to one of the DC buses P and N, and connecting the other terminal of the capacitor 21 to the other bus N, and the output voltage Vdc. If the voltage is higher than the reference voltage, the battery is charged, and if the voltage is lower than the reference voltage, the battery is discharged. The charge / discharge is repeated to smooth the output voltage Vdc.

  The regenerative power consuming unit 3 is in a conductive state during power running between the connection portion 21a of the capacitor 21 connected to the positive DC bus P and the connection portion 1a of the rectifying unit 1 to the DC bus P, and is turned off during power regeneration. The diode D5 is disposed so as to function as a switch, and a resistor 22 that consumes regenerative power during power regeneration is connected in parallel with the diode D5.

  The polarity discriminating unit 4 discriminates the polarity of the power supply voltage Ve changing as shown in FIG. 2B and outputs a signal indicating the discrimination result to the transistor selection unit 11 of the power regeneration control unit 7.

  In the transistor selection unit 11, the positive charge charged in the capacitor 21 flows on the positive side of the power supply E and the negative charge charged in the capacitor 21 on the negative side of the power supply E, according to the polarity of the power supply voltage Ve. Is generated from each pair of transistors Q1 to Q4 (each pair of transistors Q1 and Q4 and transistors Q2 and Q3), and is output to the conduction possible period setting unit 12. For example, in the example shown in FIG. 1, if the power supply voltage Ve is positive, the pair of transistors Q1 and Q4 is selected, while if the power supply voltage Ve is negative, the pair of transistors Q2 and Q3 is selected.

  The conduction possible period setting unit 12 sets a conduction possible period of a set of transistors selected according to the polarity determined by the polarity determination unit 4. For example, a period in which the power supply voltage Ve is positive is set as a conduction enabling period for the pair of transistors Q1 and Q4, while a period in which the power supply voltage Ve is negative is set as a conduction enabling period for the pair of transistors Q2 and Q3. The set conduction possible period is output to the conduction possible period correction unit 13 as a conduction possible period command.

  Note that the transistor selection unit 11 and the conduction possible period setting unit 12 may be integrated into the transistor selection unit 11 simply.

  The conduction possible period correcting unit 13 corrects each conduction possible period so that the transistors Q1 and Q4 and the transistors Q2 and Q3 are not turned on at the same time due to the switching operation delay of the transistors Q1 to Q4. Is. For example, the dead time T is given to the rising portion of each communicable period and the switching operation delay of the transistors Q1 to Q4 prevents the transistors Q1 and Q4 and the transistors Q2 and Q3 from turning on at the same time. It is what you want to do. Here, the length of the dead time T is appropriately selected according to the switching characteristics of the transistors Q1 to Q4.

  FIGS. 2C and 2D show the conduction possible periods of the set of transistors Q1 and Q4 and the set of transistors Q2 and Q3 to which the dead time T is given by the conduction possible period correction unit 13, respectively.

  Accordingly, each conduction possible period corrected by the conduction possible period correction unit 13 is output to the control signal generation unit 15 as a conduction possible command 31.

  The peak value detection unit 5 monitors the power supply voltage Ve, detects the peak value Vem, and outputs a peak value signal indicating the detection result to the regenerative operation command generation unit 14 of the power regeneration control unit 7.

  The regenerative operation command generation unit 14 compares the output voltage Vdc detected by the voltage detection unit 6 with the peak value Vem, and when the voltage Vdc becomes higher than the peak value Vem by a certain amount or more, FIG. The regenerative operation command 32 as shown in FIG. In other words, the regenerative operation command generation unit 13 sets the regenerative threshold value Vr (see FIG. 2A) when returning the regenerative power to the power source E with reference to the peak value Vem, and the output voltage Vdc is A regeneration operation command 32 is output when the regeneration threshold value Vr is exceeded.

  That is, the regenerative operation is performed at a frequency twice the frequency of the AC power source E, and the regenerative braking force becomes stronger and the rise of the voltage Vdc is suppressed as the regenerative threshold value Vr is higher. A value is required. However, even in this case, it can be made smaller than the resistor 104 in the circuit shown in FIG. Here, if the regenerative threshold value Vr is lowered, the resistance 22 can be made smaller, but on the other hand, the regenerative braking force becomes weak and the voltage Vdc rises during the off period of the regenerative operation. Therefore, the regenerative threshold value Vr is set in conformity with the regenerative braking force necessary for the load and the voltage increase of the load during power regeneration. Further, the regeneration threshold value Vr can be set dynamically according to the load fluctuation.

  The regenerative operation command 32 generated by the regenerative operation command generation unit 14 is input to the control signal generation unit 15 together with the conduction enable command 31 from the conduction possible period correction unit 13.

  The control signal generator 14 calculates the logical product of the continuity enable command 31 and the regenerative operation command 32, that is, extracts a portion where the ON signals of both commands overlap, as shown in FIGS. 2 (f) and 2 (g). In addition, the control signal 33 for actually turning on the pair of transistors Q1 and Q4 and the pair of transistors Q2 and Q3 is generated in each correction energization possible period.

  These control signals 33 are supplied to the pair of transistors Q1 and Q4 and the pair of transistors Q2 and Q3, and the pair of transistors Q1 and Q4 and the pair of transistors Q2 and Q3 are turned on for a predetermined period. Made.

  Due to this power regeneration, a regenerative current flows into the transistors Q1, Q2, Q3, and Q4. Since this regenerative current is fed back to the power supply side via the resistor 22 of the regenerative power consuming unit 3, in the transistors Q1, Q2, Q3, and Q4 Part of the regenerative current is consumed. Therefore, the capacity of the transistors Q1, Q2, Q3, and Q4 can be reduced, and the transistors Q1, Q2, Q3, and Q4 can be downsized. The resistor 22 also suppresses a steep change in the DC circuit voltage.

  However, since the regenerative current returns to the power supply side via the resistor 22, at this time, a part of the regenerative energy is consumed as heat energy as described above. However, since the potential difference between the resistors 22 is very small as compared with the voltage between the terminals, that is, the output voltage Vdc, the regenerative energy consumed by the resistors 22 can be reduced as shown in FIG. The regenerative energy consumed by the resistor 104 is much less. That is, the size of the resistor 22 can be reduced, and the loss of regenerative energy can be greatly reduced.

  Next, power regeneration by the converter device K having such a configuration will be described.

  Procedure 1: Determine the polarity of the power supply E.

  Procedure 2: The peak value Vem of the power supply voltage Ve is detected.

  Procedure 3: The output voltage Vdc is detected.

  Procedure 4: A pair of transistors Q and Q to be conducted is selected according to the determined polarity of the power supply E.

  Procedure 5: Set the conduction possible period of the selected pair of transistors Q and Q (that is, the pair of Q1 and Q4 and the pair of Q2 and Q3).

Procedure 6: The dead time T is given to the rising portion of the set conduction possible period for correction, and the conduction possible command 31 is generated. (Refer to Fig. 2 (c) and (d))
Procedure 7: It is determined whether or not the difference between the detected DC voltage Vdc and the peak value Vem exceeds the regenerative threshold value Vr. If it exceeds, the procedure proceeds to procedure 8, while if not, this procedure is repeated.

Procedure 8: A regenerative operation command 32 is generated. (See Fig. 2 (e))
Procedure 9: The logical product of the conduction enable command 31 and the regenerative operation command 32 is calculated. That is, a period in which the ON period of the conduction enabling command 31 and the ON period of the regenerative operation command 32 overlap is detected.

Procedure 10: A control signal 33 is generated based on the calculation result. That is, a signal 33 for turning on the pair of the transistors Q and Q is generated for a period in which the conduction enable command 31 and the regenerative operation command 32 are on. (Refer to Fig. 2 (f), (gd))
Procedure 11: The corresponding transistor Q and Q are turned on by the control signal 33 and power regeneration is executed for a predetermined period.

  Thus, according to this embodiment, the regeneration efficiency in power regeneration can be improved while simplifying the configuration of the detection unit. Further, since the transistor Q and the resistor 22 can be reduced in size, the device can be reduced in size and cost.

  The present invention is applied to a converter device in which power regeneration is performed, and the efficiency is improved and the size is reduced.

It is a circuit diagram which shows the structure of the converter apparatus used for the electric power regeneration method which concerns on one Embodiment of this invention. It is a timing chart which shows the control contents at the time of electric power regeneration by the electric power regeneration control part of the device. It is a circuit diagram which shows the structure of the conventional converter apparatus. It is a circuit diagram which shows the structure of the conventional PWM converter apparatus.

Explanation of symbols

K converter device D diode Q transistor E AC power supply 1 rectifying unit 2 smoothing unit 3 regenerative power consuming unit 4 polarity discriminating unit 5 peak value detecting unit 6 voltage detecting unit 7 power regenerative control unit 11 transistor selection command generating unit 12 continuity possible period setting Unit 13 conduction possible period correction unit 14 regenerative operation command generation unit 15 control signal generation unit

Claims (12)

A power regeneration method for a single-phase converter having a regeneration transistor,
The procedure to determine the polarity of the power supply,
The procedure to detect the peak value of the power supply voltage,
A procedure for detecting the output voltage;
Selecting a set of transistors to conduct based on the polarity;
A procedure for setting the conduction possible period of the selected transistor set;
A procedure for generating a continuity enable command by correcting the continuity enable period;
A procedure for generating a regenerative operation command by thresholding the output voltage;
A power regeneration method comprising: generating a control signal for turning on / off a selected transistor set based on a logical product of the conduction enable command and the regeneration operation finger.   The power regeneration method according to claim 1, wherein the correction of the conduction possible period gives a dead time to the rising portion.     2. The power regeneration method according to claim 1, wherein a signal for turning on the transistor set is generated for a period in which the ON period of the conduction enable command and the ON period of the regenerative operation command overlap.   The power regeneration method according to claim 1, wherein the threshold value is changed according to a load fluctuation.   The power regeneration method according to claim 1, wherein a period in which the output voltage exceeds the threshold is set as an ON period of the regeneration operation command. A power regeneration device for a single-phase converter having a regeneration transistor,
A polarity discriminating unit for discriminating the polarity of the power source, a crest value detecting unit for detecting a crest value of the power source voltage, an output voltage detecting unit for detecting the output voltage, and a power regeneration control unit,
The power regeneration control unit turns on the transistor based on the polarity of the power source determined by the polarity determination unit, the peak value detected by the peak value detection unit, and the output voltage detected by the output voltage detection unit. A power regeneration device that generates a control signal for controlling off.   The power regeneration control unit is selected based on a command from the transistor selection command generation unit, a transistor selection command generation unit that generates a command for selecting a transistor set based on the polarity of the power source determined by the polarity determination unit A conduction possible period setting unit that sets a conduction possible period of the set of transistors, a conduction possible period correction unit that generates a conduction possible signal by correcting the conduction possible period set by the conduction possible period setting unit, and the polarity A regenerative operation command generation unit that generates a regenerative operation command based on the polarity of the power source determined by the determination unit, the output voltage detected by the voltage detection unit, and a regenerative threshold, and a continuity enable command from the continuity enable period correction unit And a regenerative operation command from the regenerative operation command generator to generate a control signal for controlling on / off of the selected transistor set. Power regenerating apparatus according to claim 6, characterized in that a control signal generating unit.   8. The power regeneration according to claim 7, wherein a signal for turning on the transistor set is generated for a period in which the ON period of the conduction enable command and the ON period of the regenerative operation command overlap. apparatus.   The power regeneration device according to claim 7, wherein the regeneration threshold is changed in accordance with a load fluctuation.   The power regeneration device according to claim 7, wherein a period during which the output voltage exceeds the regeneration threshold is set as an ON period of the regeneration operation command.   8. The power regeneration device according to claim 7, wherein the conduction possible period is corrected by giving a dead time to the rising portion. The power regeneration device according to claim 6, wherein a regenerative power consuming unit is arranged in series on one of the DC buses of the single-phase converter.

Images