JP2013014184A - Dc feeding power source control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a power loss by a cyclic current from a forward converter to a regenerative inverter and further stably feed power with superior responsiveness when regeneration action is terminated.SOLUTION: A voltage switching control unit (24) determines whether the regenerative inverter (4) is in regenerative action based on a regenerative current detected by a regenerative current detector (7) by a condition (A), or predicts regenerative operation based on an increase in a feeder voltage detected by a voltage detector (8) by a condition (B), and switches an output voltage command value (Vd1) of a thyristor rectifier (forward converter) (1) to a regeneration start voltage (Vd2) with a changeover switch (21). As an other voltage switching control method, an output voltage detection value that is compared with the output voltage command value (Vd1) of the forward converter is switched from a feeder voltage detection value to a voltage (Vd1') that is lower than the output voltage command value (Vd1) and close to it.

Description

  The present invention relates to a control device for a DC feeder that supplies power to a DC electric vehicle, and more particularly to output voltage control of a converter (forward converter) in which regenerative inverters are connected in parallel.

  FIG. 4 shows a main circuit of the DC feeding power source. The thyristor rectifier 1 is a converter that converts AC power guided from an AC power source (not shown) through a transformer 2 into DC power whose voltage is controlled by phase control of the thyristor, and this DC output via a feeder line (overhead wire). And supplied to the electric vehicle 3 as a load. The regenerative inverter 4 converts the regenerative power generated during the regenerative operation of the electric vehicle 3 into AC power by on / off control of a self-extinguishing element such as an IGBT, and this AC power is not shown via the transformer 5. Regenerate to AC power source. In this conversion, the regenerative inverter 4 performs synchronous control for matching the voltage, frequency, and phase with the AC power supply on the regeneration side. Reference numeral 6 denotes a diode for introducing regenerative power from the electric vehicle 3 to the DC side of the regenerative inverter 4. The anode is connected to the feeder line side and the cathode is connected to the regenerative inverter side. Reference numeral 7 denotes a current detector that detects a regenerative current on the cathode side of the diode 6, and reference numeral 8 denotes a voltage detector that detects a voltage generated on the feeder line side (see, for example, Patent Document 1).

  The feeding voltage control by this DC feeding power source will be described. The thyristor rectifier 1 uses a constant voltage Vd1 set in advance as a target value, performs proportional integration (PI) calculation of the deviation from the wire voltage, performs constant voltage control (AVR), and uses the voltage Vd1 as a control output voltage. Electric power is supplied to the electric car 3 through. The regenerative inverter 4 starts a regenerative operation when the feeder voltage exceeds a voltage Vd2 that is higher than the feeder control voltage Vd1 and slightly lower than the overvoltage detection level due to regenerative energy when the electric vehicle 3 is braked. Then, voltage control (AVR) is performed so that the feeder voltage can be suppressed in the vicinity of the voltage Vd2 (see, for example, Patent Document 2).

JP 59-50826 Japanese Patent Laid-Open No. 61-94833

  In FIG. 4, the thyristor rectifier (converter) 1 controls the output voltage so that the feeding voltage does not drop below the set voltage Vd 1, and feeds a direct current to the electric vehicle 3. The regenerative inverter 4 is always in a standby state in which the operation is stopped, and when the feeder voltage rises due to the regenerative energy when the electric vehicle 3 is braked and exceeds the set voltage Vd2, the feeder voltage is Regenerative control is performed so as not to exceed the set voltage Vd2.

  During this regeneration control, the feeder voltage is controlled in the vicinity of the set voltage Vd2. However, since the thyristor rectifier 1 is AVR controlled to the set voltage Vd1 lower than the voltage Vd2, the AVR control voltage feeder voltage of the thyristor rectifier 1 is The PI control state in which the control amount is narrowed down to the minimum (lower limit value) so as to be Vd1 is maintained. Therefore, the regenerative operation of the electric vehicle 3 is finished, and the response delay of the AVR function when power is supplied from the thyristor rectifier 1, until the target voltage Vd1 is established from the lowest voltage control output of the thyristor rectifier 1. When a delay occurs and the electric vehicle shifts to powering operation in a short time after the end of regenerative operation, there is a case where acceleration response is poor due to insufficient feeder voltage at the start of powering operation.

  In order to eliminate such inconvenience, in Patent Document 3 (Japanese Patent Laid-Open No. 55-3180), the regenerative operation start voltage Vd2 of the regenerative inverter 4 is set slightly lower than the control voltage Vd1 of the thyristor rectifier (converter) 1. It has been proposed that a circulating current is allowed to flow from the thyristor rectifier 1 to the regenerative inverter 4 in a no-load state (small current region). According to this method, the output voltage of the thyristor rectifier 1 is maintained at a value close to the voltage Vd1 even during the regenerative operation of the electric vehicle. At the end of the regenerative operation, the output of the thyristor rectifier 1 is good in response from the value close to the voltage Vd1. , Power feeding can be resumed.

  However, even in a no-load state, there is a problem that a circulating current continues to flow from the thyristor rectifier 1 to the regenerative inverter 4 and a loss occurs in the switching element or the like due to the circulating current.

  An object of the present invention is to provide a control device for a DC feeding power source that eliminates power loss due to circulating current and can stably supply power with good responsiveness at the end of a regenerative operation.

  In order to solve the above-described problem, the present invention provides a switching control means for switching the output voltage command value Vd1 of the forward converter to the regeneration start voltage Vd2 during the regenerative operation of the regenerative inverter or when a regenerative operation is expected, or It comprises switching control means for switching the output voltage detection value to be compared with the output voltage command value Vd1 of the forward converter from the feeder voltage detection value to a voltage Vd1 ′ lower than the output voltage command value Vd1 and close thereto. It is characterized by the configuration of

(1) a forward converter that feeds DC power, which is controlled from AC power to a voltage that matches the output voltage command value Vd1, to an electric vehicle via a feeder line;
The forward converter is connected in parallel on the direct current side and can generate regenerative power during regenerative operation of the electric vehicle. When the electric wire voltage exceeds the regenerative start voltage Vd2 higher than the output voltage command value Vd1, the regenerative power is exchanged with AC. In the DC feeding power source equipped with a regenerative inverter that converts to power and regenerates to the AC power source side,
The regenerative inverter is provided with switching control means for switching the output voltage command value Vd1 of the forward converter to the regeneration start voltage Vd2 when the regenerative inverter is in a regenerative operation or when a regenerative operation is expected.

(2) a forward converter that feeds DC power, which is controlled from AC power to a voltage that matches the output voltage command value Vd1, to the electric vehicle via a feeder line;
The forward converter is connected in parallel on the direct current side and can generate regenerative power during regenerative operation of the electric vehicle. When the electric wire voltage exceeds the regenerative start voltage Vd2 higher than the output voltage command value Vd1, the regenerative power is exchanged with AC. In the DC feeding power source equipped with a regenerative inverter that converts to power and regenerates to the AC power source side,
When the regenerative inverter is in a regenerative operation or when a regenerative operation is expected, an output voltage detection value to be compared with the output voltage command value Vd1 of the forward converter is set to be lower than the output voltage command value Vd1 and close to it. Switching control means for switching to the voltage Vd1 ′ is provided.

  As described above, according to the present invention, when the regenerative inverter is in the regenerative operation or when a regenerative operation is expected, the output voltage command value Vd1 of the forward converter is switched to the regeneration start voltage Vd2, or the forward converter Since the output voltage detection value to be compared with the output voltage command value Vd1 is switched from the feeder voltage detection value to the voltage Vd1 ′ lower than the output voltage command value Vd1 and close thereto, the circulating current from the forward converter to the regenerative inverter In addition, power can be supplied stably and with good responsiveness at the end of the regenerative operation.

FIG. 3 is a circuit diagram of a main part of the DC feeder power supply according to the first embodiment. FIG. 3 is a voltage-current characteristic diagram in switching control according to the first embodiment. FIG. 3 is a circuit diagram of a main part of a DC feeder power supply according to a second embodiment. The main circuit diagram of DC feeding power supply.

(Embodiment 1)
FIG. 1 is a main part circuit diagram of a DC feeding power source showing the present embodiment, and circuits equivalent to those in FIG. 4 are denoted by the same reference numerals.

  The control circuit of the regenerative inverter 4 is set with a regenerative operation start voltage Vd2, and the voltage controller 11 performs a proportional integral (PI) calculation on the deviation between the voltage Vd2 and the feeder voltage detected by the voltage detector 8, and this calculation is performed. As a result, the pulse width of the PWM pulse output (frequency and phase is synchronized) of the PWM control unit 12 is controlled, and when the electric power can be regenerated from the electric vehicle 3 and the electric wire voltage exceeds the voltage Vd2, the regenerative operation is started. Regenerate to the side.

  In the control circuit of the thyristor rectifier 1, the voltage Vd1 or Vd2 switched by the changeover switch 21 is set as a target value, and the voltage controller 22 proportionally integrates the deviation between this voltage and the feeder voltage detected by the voltage detector 8 ( PI) is calculated, and the result of this calculation is used as a phase control command for the phase controller 23 to control the firing phase of the thyristor of the thyristor rectifier 1. When the feeder voltage falls below the voltage Vd1 or Vd2, the voltage Increase to Vd1 or Vd2.

  The voltage switching control unit 24 controls the output of the selector switch 21 to the voltage Vd1 or Vd2, and the switching condition at this time is the regenerative current value detected by the regenerative current detector 7 or the feeder voltage detected by the voltage detector 8. Decide on. This switching condition is the switching condition (B) based on the electric wire voltage when the switching condition (A) is based on the regenerative current.

  The switching condition (A) is the switching condition during the regenerative operation. When the regenerative current is zero, the output of the changeover switch 21 is switched from the voltage Vd2 to the voltage Vd1, and when the feeder voltage rises and the regenerative current is generated, the changeover switch 21 is switched. Is switched from the voltage Vd1 to the voltage Vd2.

  The switching condition (B) is a switching condition when a regenerative operation is expected. When the feeder voltage is Vd2 or lower and Vd1 or higher and a predetermined voltage value Vd3 or lower, the output of the changeover switch 21 is changed from voltage Vd2 to voltage. When the feeder voltage exceeds the voltage value Vd3, the output of the changeover switch 21 is switched from the voltage Vd1 to the voltage Vd2.

  FIG. 2 is a voltage-current characteristic diagram in switching control of the thyristor rectifier shown in FIG. The voltage Vd1 in FIG. 1 is an output voltage command value of the thyristor rectifier 1 in the no-load or power running operation of the electric vehicle, and the voltage Vd2 is a voltage at the start of the regenerative operation of the regenerative inverter 4, and is set to Vd1 <Vd2. For example, the condition (A) is set and the voltage switching control unit 24 switches the voltages Vd1 and Vd2 depending on whether the regenerative current is zero or not.

  The feeder voltage control under this condition (A) continues to control the thyristor rectifier 1 so that the output voltage is maintained at Vd1 with the voltage Vd1 as a voltage command value when there is no load or the electric vehicle 3 is in power running. When the electric vehicle 3 enters the regenerative operation and the electric wire 3 can be regenerated and the electric wire voltage rises to Vd2, the regenerative inverter 4 starts the regenerative operation and supplies the regenerative current to the AC power supply side.

  When the regenerative current is generated, the switching control unit 24 switches the changeover switch 21 to the voltage Vd2 side and controls the output voltage of the thyristor rectifier 1 to Vd2. In this control state, the output voltage control of the thyristor rectifier 1 is less than the voltage Vd2 or the voltage controller (AVR) by setting the voltage equal to or lower than the voltage Vd2 at which the regenerative inverter 4 performs the regenerative operation by a constant voltage (for example, 10V). Therefore, the circulating current from the thyristor rectifier 1 to the regenerative inverter 4 does not flow, and no power loss due to the circulating current occurs.

  Next, when the regenerative operation of the electric vehicle 3 ends or becomes no load, and the feeder voltage drops from Vd2, the regenerative current becomes zero, so that the switching control unit 24 switches the voltage command from Vd2 to Vd1. . By this switching, the output voltage control of the thyristor rectifier 1 drops from Vd2 toward Vd1. At this time, it is assumed that the output voltage of the thyristor rectifier 1 drops to a value lower than Vd1 due to the control delay of the voltage controller 22 or the like, but the zero determination of the regenerative current is detected early. That is, the end of the operation of the regenerative inverter is determined to end when the DC voltage drops by a certain voltage from the time of the regenerative operation, thereby suppressing the undershoot low. At the end of the regenerative operation, the thyristor rectifier 1 supplies the voltage Vd1 during the power running operation. The power supply can be controlled stably with good responsiveness.

  In the case of the switching condition (B) based on the voltage Vd3, the same switching control can be performed, power loss due to the circulating current can be eliminated, and power can be stably supplied with good responsiveness at the end of the regenerative operation. In this case, even if the difference between the voltages Vd1 and Vd2 is about 100V, the same effect can be obtained by appropriately setting the voltage Vd3 to the intermediate value {= (Vd1 + Vd2) / 2}. it can.

(Embodiment 2)
FIG. 3 is a circuit diagram of a main part of the DC feeder power supply showing the present embodiment. The portion different from FIG. 1 is that the voltage command value Vd1 is substituted for the feeder voltage detection value to the thyristor rectifier 1 during the regenerative operation. The voltage Vd1 'is low and close to that. For example, the voltage Vd1 ′ is set to a voltage lower by 10V than the voltage Vd1.

  The changeover switch 25 switches between the feeder voltage detection value detected by the voltage detector 8 and the set voltage Vd1 ', and the changeover control unit 24 performs this changeover according to the changeover conditions (A) and (B).

  For example, the feeder voltage control according to the condition (A) continues to control the thyristor rectifier 1 so that the output voltage is maintained at Vd1 using the voltage Vd1 as a voltage command value when there is no load or the electric vehicle 3 is in power running. When the electric vehicle 3 enters the regenerative operation and the electric wire 3 can be regenerated and the electric wire voltage rises to Vd2, the regenerative inverter 4 starts the regenerative operation and supplies the regenerative current to the AC power supply side.

  When this regenerative current is generated, the switching control unit 24 switches the changeover switch 25 to the voltage Vd1 'side, and controls the output voltage control of the thyristor rectifier 1 to the upper limit value of the voltage controller (AVR) 22. In this control state, the voltage is lower than the voltage Vd2 at which the regenerative inverter 4 performs the regenerative operation, the circulating current from the thyristor rectifier 1 to the regenerative inverter 4 does not flow, and no power loss due to the circulating current occurs.

  Next, when the regenerative operation of the electric vehicle 3 ends or becomes no load and the feeder voltage drops from Vd2, the regenerative current becomes zero, and the switching control unit 24 changes the feedback voltage from Vd1 ′ to the voltage detection value. Switch. By this switching, the output voltage control of the thyristor rectifier 1 is at a value close to the voltage VD2 or at the upper limit value, and decreases from that value toward the voltage Vd1. At this time, the output voltage of the thyristor rectifier 1 is controlled from a value close to the voltage Vd2 or the upper limiter value due to a control delay of the voltage controller 22 and the like, without causing an extreme undershoot, and at the end of the regenerative operation, the thyristor rectifier From 1, the power can be supplied stably and with good responsiveness toward the voltage Vd1 during powering operation.

  In the case of the above switching condition (B) based on the voltage Vd3 within the range of the voltages Vd2 and Vd1, the same switching control can be performed, power loss due to the circulating current is eliminated, and a stable response is achieved at the end of the regenerative operation. Power can be supplied with good quality.

  As in the first embodiment, this embodiment can control the output voltage of the thyristor rectifier 1 during power running and regenerative operation, eliminates power loss due to circulating current, and is stable and responsive at the end of the regenerative operation. Power can be supplied.

(Modification)
In the first and second embodiments, the switching based on the determination of the condition (A) or (B) eliminates the vibrational switching of the control state by providing a hysteresis, thereby enabling stable switching.

  Moreover, it replaces with the thyristor rectifier 1, and it can apply to the apparatus used as the forward converter (converter) which used IGBT etc. as the switching control element, and can obtain an equivalent effect.

DESCRIPTION OF SYMBOLS 1 Thyristor rectifier 3 Electric vehicle 4 Regenerative inverter 6 Diode 7 Current detector 8 Voltage detector 11 Voltage controller 12 PWM control part 21 Changeover switch 22 Voltage controller 23 Phase controller 24 Voltage changeover control part 25 Changeover switch

Claims (2)

A forward converter that feeds DC power, which is controlled from AC power to a voltage that matches the output voltage command value Vd1, to the electric vehicle via feeders;
The forward converter is connected in parallel on the DC side and can generate regenerative power during regenerative operation of the electric vehicle. When the electric wire voltage exceeds a regenerative start voltage Vd2 higher than the output voltage command value Vd1, In the DC feeding power source equipped with a regenerative inverter that converts to power and regenerates to the AC power source side,
DC power supply comprising switching control means for switching the output voltage command value Vd1 of the forward converter to the regeneration start voltage Vd2 during the regeneration operation of the regeneration inverter or when a regeneration operation is expected. Control device. A forward converter that feeds DC power, which is controlled from AC power to a voltage that matches the output voltage command value Vd1, to the electric vehicle via feeders;
The forward converter is connected in parallel on the direct current side and can generate regenerative power during regenerative operation of the electric vehicle. When the electric wire voltage exceeds the regenerative start voltage Vd2 higher than the output voltage command value Vd1, the regenerative power is exchanged with AC. In the DC feeding power source equipped with a regenerative inverter that converts to power and regenerates to the AC power source side,
When the regenerative inverter is in a regenerative operation or when a regenerative operation is expected, an output voltage detection value to be compared with the output voltage command value Vd1 of the forward converter is set to be lower than the output voltage command value Vd1 and close to it. A control apparatus for a DC feeding power source, comprising switching control means for switching to voltage Vd1 '.

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