JPH0767294B2 - Flywheel energy storage device braking system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention, for example, is a flywheel that stores excess power of an electric power line in a flywheel and releases the stored power when power is insufficient to compensate for the power shortage. The present invention relates to a braking device for an energy storage device.

[Conventional technology]

FIG. 3 is a circuit diagram showing a configuration of a braking device of a conventional flywheel energy storage device described in, for example, Japanese Patent Laid-Open No. 62-281736, in which 1 is a DC feeding circuit (hereinafter referred to as a train). 2) ground wire, 3 switch, 4 DC reactor, 5 capacitor, 6 main circuit of power converter (hereinafter referred to simply as power converter), 7 three-phase induction machine, 8 This is a flywheel connected to this three-phase induction machine.

The power converter 6 is a semiconductor switching element, and in this example is an inverter in which gate turn-off thyristors (hereinafter referred to as GTOs) 12 to 17 are connected in a 6-phase bridge.
Diodes 18 to 23 are connected in anti-parallel to each of ˜17.

Reference numeral 100 denotes a four-quadrant chopper, which is inserted between the smoothing circuit including the DC reactor 4 and the capacitor 5 and the power converter 6.

The 4-quadrant chopper 100 includes a GTO 101, diodes 111 and GTO 102 connected in anti-parallel to the GTO 101, diodes 112 and GTO 103 connected in anti-parallel to the GTO 101, and diodes connected in anti-parallel to the GTO 101.
113, GTO104 and diode 114, GT connected in anti-parallel to this
It has a smoothing reactor 200 inserted between the connection point of O101 and 102 and the connection point of GTO103 and 104, and the series circuit of GTO101 and 102 is connected between the terminals of the capacitor 5 and GTO103.
The series circuit of 104 is connected between the DC side terminals of the power converter 6.

Reference numeral 121 denotes a filter capacitor inserted between the DC side terminals of the power converter 6, and a voltage detector 251 for detecting the DC input voltage Vd of the power converter 6 is connected in parallel to the filter capacitor 121.

A current detector 241 detects a direct current Idin (an input current of the power converter 6) flowing in the direct current circuit of the power converter 6.

A multiplier 26 multiplies the DC current Idin and the DC input voltage Vd to calculate the input power P.

The voltage controller 351 compares calculating a DC input voltage Vd of the power converter 6 for detecting the input reference voltage Vd ^* and the voltage detector 251, a gate as the input DC voltage Vd becomes the input reference voltage Vd ^* A control signal is created and supplied to the gate controller 361.

The gate controller 361 sends out a gate pulse having a pulse width corresponding to the magnitude of the gate control signal.

In this example, the stored / released power reference value is created by the train line current reference generator 321 and the multiplier 261. The train line current reference generator 321 creates a current reference value Id ^* by comparing the voltage detection value Ed of the voltage detector 25 with the train line voltage reference value Ed ^* .

The current reference value Id ^* is multiplied by the voltage detection value Ed in the multiplier 261. The output of the multiplier 261 is the stored / released power reference value P ^* and is compared with the converted power P of the power converter 6 which is the output of the multiplier 26 in the power controller 31.

The power controller 31 calculates the required slip frequency Δf of the induction machine 7.

A speed detector 32 detects the rotation speed f ₀ of the induction machine 7. Reference numeral 33 is a frequency controller to which the outputs of the power controller 31 and the speed detector 32 are introduced.

Reference numeral 34 denotes an oscillator, which outputs a frequency signal corresponding to the frequency command signal f _S sent from the frequency controller 33 to the gate pulse generator.
Supply to 35.

Next, the operation will be described. This device takes in the direct current Idin from the trolley wire 1 when the electric power Ed of the trolley wire is above a predetermined value to store energy in the flywheel 8, and when the electric power Ed is below a predetermined value, discharges the current to the trolley wire. .

At the time of energy storage, the power converter 6 converts the DC input voltage Vd taken through the four-quadrant chopper 100 into DC power and supplies the DC power to the induction machine 7, and the induction machine 7 is operated in a row mode.

During this energy storage, the output P ^* of the multiplier 261 and the multiplier 26
The required slip frequency Δf of the induction machine 7 is calculated from the output P (actual converted power of the power converter 6) of the power controller 31 and the oscillation frequency of the oscillator 34 changes according to the addition frequency f = Δf + f ₀ . According to the oscillation frequency, a gate pulse is supplied from the gate pulse generator 35 to the gates of the GTOs 12 to 17 of the power converter 6, the GTOs 12 to 17 are switching-controlled, and the induction line 7 and the flywheel 8 are connected to the train line 1 From this, the energy of power P ^* (reference value of stored energy and released energy) is stored.

Further, when the above energy is dissipated, the power converter 6 converts the stored energy of the flywheel 8 released through the induction machine 7 into DC power, and sends it to the train line 1 via the four-quadrant chopper 100 to send it to the train line. Compensate for voltage drops.

Next, the operation of the 4-quadrant chopper 100 will be described. It is now assumed that the flywheel 8 is in the energy storage mode in which energy is absorbed from the trolley wire 1.

At this time, if Ed> Vd ^* , the 4-quadrant chopper 100 is GTO1.
01 is driven by a chopper, and diode 112 becomes a power line step-down chopper that performs flywheel operation.
The DC input voltage Vd of is stepped down so as to become the input reference voltage Vd ^* .

On the other hand, when Ed <Vd ^* , the GTO 101 is turned on, the GTO 104 is driven by the chopper, and the diode 113 becomes the power boost chopper that performs the series diode operation.

Further, when the flywheel 8 is in the discharge mode in which energy is emitted to the trolley wire 1, when EdVd ^* , the four-quadrant chopper 100 turns on the GTO103, the GTO102 is driven by the chopper, and the diode 111 performs the series diode operation. It becomes a regenerative booster chopper.

On the contrary, when Ed <Vd ^* , the GTO103 is chopper-driven,
The diode 114 is a regenerative step-down chopper that performs a flywheel operation.

[Problems to be Solved by the Invention]

Since the braking device of the conventional flywheel energy storage device is configured as described above, the power supply of the train line 1 is indeterminate in order to perform the constant voltage control by the chopper.

If the train line 1 is disconnected, the input voltage is not maintained at a predetermined value, the output voltage of the power converter 6 changes, and the induction machine 7
A large reactive current flows between and, and the operation of the power converter 6 cannot be continued.

Therefore, even when the flywheel 8 is decelerated, it is necessary to release energy to the train line 1, and when there is no train running on the train line at night, there is nothing to absorb the released energy. There was a problem that the flywheel could not be slowed down and stopped.

The present invention has been made to solve the above-mentioned problems, and by decelerating the flywheel without releasing energy to the DC power supply, the flywheel can be stopped arbitrarily regardless of the state of the DC power supply. An object of the present invention is to obtain a braking device for a flywheel energy storage device that can be operated.

[Means for Solving the Problems]

A braking device for a flywheel energy accumulator according to the present invention includes a first switch that disconnects a chopper from a DC power source, a braking resistor that consumes regenerative power of the chopper, and a second switch that turns on the braking resistor. A switch, a calculator that detects changes in the input voltage of the power converter, a frequency controller that controls the switching frequency of the power converter by adding the calculator output and the frequency command of the power converter, and a regenerative controller. A stop sequence generator that controls the frequency controller and the opening / closing control of the switch during braking is provided.

[Action]

During regenerative braking according to the present invention, the first switch is opened to disconnect the chopper from the DC power source, the second switch is closed to apply the braking resistance, and the change in the input voltage of the power converter is calculated during that period. Detector, and based on the sum of the output of this calculator and the frequency command of the power converter, suppress the input voltage of the power converter by the frequency controller, and suppress excessive reactive current between the power converter and induction machine. At the same time, the flywheel is stopped while restarting the operation of the chopper and consuming the regenerative electric power of the chopper to the braking resistance, so that the energy absorption by the DC power supply becomes unnecessary.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 1-8, 12-23, 25, 26, 31-35, 100-104, 111
The parts indicated by 114, 121, 200, 241, 251, 261, 321, 351, 361 are the same as in FIG. That is, the following portion is added to the configuration of FIG. 3 in FIG.

That is, 41 is a braking resistor for consuming the regenerative power of the 4-quadrant chopper 100. Reference numeral 40 is a second switch which is a second switch for causing the braking resistance 41 to be applied to the input side of the four-quadrant chopper 100. In addition, in FIG.
The switch indicated by 3 will be referred to as a first switch.

42 is a calculator for calculating the difference ΔV = Vd−Vd ^* between the input power Vd of the power converter 6 and the input reference voltage Vd ^*, and 43 is a switching relay for switching the stored energy release power reference P ^* to 0, The switching relay 43 is inserted between the output end of the multiplier 261 and the input end of the power controller 31.

44 is the slip frequency Δ added by the frequency controller 33.
f is a switching relay that switches the output of the power controller 31 to the output of the calculator 42, and is inserted between the output end of the power controller 31, the output end of the calculator 42, and the input end of the frequency controller 33. .

45 is a switching relay that switches the other signal added by the frequency controller 33, the rotational speed f _0, to the output of the ramp generator 47, and 46 is the rotational speed f ₀ that is the input signal of the ramp generator 47.
Switching relay to switch to 0, 48 is a 4-quadrant chopper 100
Is a switching relay that turns on and off the gate pulse of.
N, OFF controlled.

The stop sequence generator 50 turns on the changeover relay 43 by turning on the stop button 50a, and the first signal through the delay circuit 51.
The switch 3 and the switching relay 48 are turned off and the switching relay 44 is turned on, and when the first switch 3 is closed, the second switch 40 is turned on, Along with that,
The switching relays 48, 45, 46 are configured to be turned on.
The configuration of the other parts is the same as the conventional example shown in FIG.

Next, the operation will be described. FIG. 2 is a flowchart showing the flow of operation of the embodiment shown in FIG. First, when the stop button 50a is pressed in step ST1, the switching relay 43 is turned on, and the power reference value P ^*, which is the input of the power controller 31, is set to zero. As a result, the required slip frequency Δf at which the converted power P of the power converter 6 becomes 0 in step ST2 is the power controller.
Calculated at 31, plus the rotational speed f ₀ and its calculation result to the frequency controller 33, the oscillation frequency of the oscillator 34 is controlled.

This oscillation frequency controls the GTO chopper frequency of the power converter 6 via the gate pulse generator 35, and as a result, the slip of the induction machine 7 is controlled.

As a result, only a slight loss of the power converter 6 is regenerated from the flywheel 8 via the induction machine 7, and the output current of the 4-quadrant chopper 100 is 0, which creates a balanced operation state.

At the same time, the timer of the delay circuit 51 is started in step ST3,
When this timer expires after a predetermined time (step
ST4), the switching relay 48 is turned off, and in step ST5, the GTO 101 to 104 of the 4-quadrant chopper 100 are turned off,
The 4-quadrant chopper 100 stops operating.

At this time point, the output current of the four-quadrant chopper 100 is in a balanced state of 0, so that the transient fluctuation of the input voltage does not occur. When the 4-quadrant chopper 100 is turned off, the first switch 3
Is issued. As a result, the train line 1 is released from the 4-quadrant chopper 100 in step ST6.

Further, the switching relay 44 is turned on, the slip frequency Δf becomes the output of the calculator 42 in step ST7, the power control is stopped, and instead the command value of the input voltage Vd, that is, the deviation from the input reference voltage Vd ^* , is followed ^. , The slip frequency Δf is determined.

That is, when Vd> Vd ^* , the slip frequency Δ
Let f be positive, and give a positive slip of the induction machine 7. As a result, the induction machine 7 is put into a running state, power flows out of the power converter 6, the capacitor 121 is discharged by this power, and the input voltage Vd of the power converter 6 drops.

On the other hand, when Vd <Vd ^* , the slip frequency Δf becomes negative, so the induction machine 7 is given a negative slip and enters the regenerative state. As a result, power flows into the power converter 6, the capacitor 121 is charged with this power, and the input voltage Vd rises. In this way, the input voltage Vd is held so as not to deviate from the predetermined value Vd ^* .

Next, when it is confirmed in step ST8 that the opening of the first switch 3 has been completed, a closing command of the second switch 40 is issued to close the braking resistor 41. Upon completion of closing the second switch 40 (step ST9), the switching relays 48, 45, 46 are turned on.
(Step ST10).

As a result, in step ST11, the chopper gate of the 4-quadrant chopper 100 is turned on, the chopper 100 starts operating, and the 4-quadrant chopper 100 can perform constant voltage control again. At the same time, the signal from which the frequency command f _s is calculated in step ST12 switches from the rotation speed f ₀ to the output of the ramp generator 47.

Since the input of the ramp generator 47 is given the rotational speed f ₀ before that, the lamp output = f ₀ at the time of switching, and shockless switching is performed.

After that, the lamp input is switched to 0 in step ST12, and the lamp output starts decreasing at a predetermined deceleration rate. As a result, the frequency command f _s also decreases, and when f _s <f ₀ , the induction machine 7 has a negative slip and is in a regenerative state. Then, the energy of the flywheel 8 is regenerated to the power conversion supply 6.

This regenerated electric power charges the capacitor 121 and raises the input voltage Vd, but is discharged to the braking resistor 41 by the constant voltage control of the four-quadrant chopper 100.

That is, when Vd> Vd ^* , the gate pulse width of the GTO103 increases and the charge of the capacitor 121 is changed to the GTO103 and the reactor 20.
It is discharged through the route of 0, diode 111, reactor 4, second switch 40, and braking resistor 41. In this way, the energy of the flywheel 8 is consumed by the braking resistance 41, and the flywheel 8 is stopped.

Although the switching relay 44 is in the ON state in the stop process, Vd = Vd ^* holds as long as the constant voltage control of the chopper normally operates as described above, so the output Δf is usually 0.

Although the stop sequence generator 50 has been described as a relay or a gate logic circuit in the above embodiment, the same effect can be obtained by implementing the flowchart of FIG. 2 as software and realizing it by a microprocessor.

Further, although the above embodiment has been described with respect to the case of being connected to the train line 1, the same effect can be obtained even if a DC power supply such as a DC power transmission line or a DC bus of a factory power supply is used instead of the train line 1.

Further, the chopper is not limited to the four-quadrant chopper, and the operation area is limited, so that the same effect can be obtained when the three-quadrant or the two-quadrant chopper is used.

Further, in the above-mentioned embodiment, the signal compared by the power controller is treated as electric power, but there is no problem even if it is treated as electric current. That is, the multiplier 261 is omitted, and the command value of the current Id is directly given to However, the operation is exactly the same.

〔The invention's effect〕

As described above, according to the present invention, when the flywheel is stopped, first, the power converter input is controlled to 0, then the chopper is turned off, and at the same time, the slip is controlled in the induction machine by the change in the power converter input power. After that, the braking resistance is turned on, the chopper is turned on to cause the braking resistance to consume energy, and the flywheel is stopped, so it is possible to suppress fluctuations in the input voltage of the power converter even after the DC power supply is disconnected. The flywheel can be braked and stopped at any time regardless of the state of the DC power supply.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a braking device for a flywheel energy storage device according to an embodiment of the present invention, FIG. 2 is a flow chart showing a flow of operation of the present invention, and FIG. 3 is a conventional flywheel energy. It is a block diagram of the braking device of the energy storage device. 1 is a train line (DC power supply), 3 is a first switch, 6 is a power converter, 7 is an induction machine, 8 is a flywheel, 33 is a frequency controller, 40 is a second switch, and 41 is a brake. A resistor, 42 is a calculator, 50 is a stop sequence generator, and 100 is a chopper. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A chopper that is connected to a DC power supply and that performs a step-up chopper operation and a step-down chopper operation to generate a DC variable voltage, a power converter that is connected to the chopper and that converts DC into an AC of variable frequency, and this power. An induction machine connected to the converter, a flywheel connected to the induction machine, a frequency controller that controls the input power of the power converter, and a first switch that disconnects the chopper from a DC power supply, A second switch that applies a braking resistance to the chopper instead of the DC power source, an arithmetic unit that detects a change in the variable DC voltage and calculates a voltage deviation, and the frequency controller when the flywheel is stopped. After the converted power of the power converter is set to 0, the operation of the chopper is stopped,
After the voltage deviation is added to the output frequency of the power converter, the first switch is opened and the second switch is turned on, and at the same time, the operation of the chopper is restarted and the frequency controller is restarted. A braking device for a flywheel energy storage device, comprising: a stop sequence generator that performs a sequence operation to reduce an output frequency of the power converter at a predetermined deceleration rate.