JP3418780B2 - Thyristor DC power supply - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thyristor forward converter for converting AC power from a power source into DC power and giving it to a load, a thyristor reverse converter for converting regenerative power from a load into AC power, and a thyristor order. The present invention relates to an improvement of a thyristor DC power supply device including a switching control unit that controls switching between a converter and a thyristor inverse converter.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing a configuration example of a conventional thyristor DC power supply device. This thyristor DC power supply device includes three diode pairs 1a-connected in series.
1b, 1c-1d, 1e-1f are connected in parallel, and the thyristor forward converter 1 (power running) in which each phase power of three-phase AC power from a power supply (not shown) is applied to each connection point of each pair Side converter) and this thyristor forward converter 1
And a thyristor inverse converter 2 (regeneration-side converter) connected in anti-parallel to. The thyristor inverse converter 2 is
Three pairs of series-connected diode pairs 2a-2b, 2c-
2d, 2e-2f are connected in parallel, and each phase power line of three-phase AC power is connected to each connection point of each pair.

Further, in this thyristor DC power supply device, an inverter 5 having a smoothing capacitor 5a built therein as a load is connected through a DC circuit breaker 19, and the inverter 5
DC reactor 4 for smoothing the output current to the inverter 5, the DC voltage detector 6 for detecting the output voltage to the inverter 5 and the voltage of the regenerative power from the inverter 5, the output current to the inverter 5 and the inverter 5 A DC current detector 7 for detecting the current of regenerative power, a setter 8 for setting an output voltage value to the inverter 5 and a voltage value of regenerative power from the inverter 5, and a voltage value set by the setter 8 and To reduce the difference between the voltage values detected by the DC voltage detector 6,
The voltage control unit 9 outputs a current instruction value for controlling the output current to the inverter 5 and the current of the regenerative power from the inverter 5.

In addition, this thyristor DC power supply device has a DC current detector 7 and a current instruction value output from the voltage controller 9.
The current control unit 10 that controls the phase of the thyristor forward converter 1 and the thyristor inverse converter 2 so that the difference between the detected current values becomes small, and the thyristor forward converter 1 and the thyristor according to an instruction from the current control unit 10. The gate pulse control unit 20 that switches the inverse converter 2 and determines the phase of each pulse to each gate of the thyristors 1a to 1f and 2a to 2f of the thyristor forward converter 1 and the thyristor inverse converter 2.
And a gate pulse generator 12 that outputs a gate pulse according to an instruction from the gate pulse control unit 20 to drive the thyristor forward converter 1 and the thyristor inverse converter 2.
And a gate pulse generator 13. The gate pulse control unit 20 performs switching according to the direction of the current detected by the DC current detector 7, which is determined by the current control unit 10.

The operation of the thyristor DC power supply device having such a configuration will be described below. In this thyristor DC power supply device, the thyristor forward converter 1 is driven by the gate pulse generator 12 to rectify the three-phase AC power from the power supply. The rectified DC power is smoothed by the DC reactor 4 and given to the inverter 5. In the inverter 5, the DC power is smoothed by the smoothing capacitor 5a and then converted into AC power of a predetermined frequency to drive a load such as an electric motor (not shown).

At this time, the voltage controller 9 controls the output current to the inverter 5 so that the difference between the voltage value set by the setter 8 and the voltage value detected by the DC voltage detector 6 becomes small. Outputs the current instruction value. The current control unit 10 is
Phase control of the thyristor forward converter 1 is performed so that the difference between the current instruction value and the current value detected by the DC current detector 7 becomes small. The gate pulse control unit 20 includes the current control unit 10
The phase of each pulse to each gate of the thyristors 1a to 1f of the thyristor forward converter 1 is determined by the instruction from the gate pulse generator 12, and the gate pulse generator 12 outputs the gate pulse according to the instruction from the gate pulse control unit 20. Then, the thyristor forward converter 1 is driven.

When regenerative electric power is generated by regenerative braking of the electric motor which is a load and a current flows backward, the current control unit 10
Is determined by the direct current detector 7 based on the current value detected, and the gate pulse controller 20 switches from the gate pulse generator 12 to the gate pulse generator 13 according to the determination. As a result, the thyristor forward converter 1 is stopped and the thyristor inverse converter 2 is driven.
At this time, the voltage control unit 9 controls the current of the regenerative power from the inverter 5 so that the difference between the voltage value set by the setting unit 8 and the voltage value detected by the DC voltage detector 6 becomes small. Output the indicated value. The current controller 10 controls the phase of the thyristor inverse converter 2 so that the difference between the current instruction value and the current value detected by the direct current detector 7 becomes small.

The gate pulse control unit 20 is the current control unit 1
By the instruction from 0, the phase of each pulse to each gate of the thyristors 2a to 2f of the thyristor inverse converter 2 is determined,
The gate pulse generator 13 outputs a gate pulse according to an instruction from the gate pulse control unit 20 to drive the thyristor inverse converter 2. As a result, the thyristor reverse converter 2 converts the regenerative power into the three-phase AC power having the same frequency as the three-phase AC power from the power supply and returns it to the power supply. The DC circuit breaker 19 operates to cut off the current when the output current to the inverter 5 or the current of the regenerative power from the inverter 5 exceeds a predetermined value and becomes excessive, and the thyristor forward converter 1 and the thyristor reverse conversion circuit. Of the thyristors 1a to 1f of the container 2,
Protects 2a-2f.

[0009]

Since the conventional thyristor DC power supply device is configured as described above, the power supply voltage (input voltage) input to the power-driving side thyristor forward converter 1 and the regenerative side. The voltage (output voltage) of regenerative power returned from the thyristor inverse converter 2 to the power supply is equal. However, in order to secure the commutation allowance angle (phase angle from the end of commutation to the time when the thyristor is turned off) of the regenerative-side thyristor inverse converter 2, the ratio of the output voltage and the input voltage is set to a constant value by phase control. Since it must be set to the following, the power supply power factor determined by the ratio of the output voltage / the input voltage becomes a certain value or less. For this reason, the power supply power factor during power running is poor in applications in which power running is extremely frequent, such as when the inverter 5 that is a load drives an electric motor.

Further, since the thyristor of the thyristor forward converter 1 on the power running side has the smoothing capacitor 5a of the inverter 5, an overcurrent does not occur even in the case of commutation failure caused by a power failure or the like, but it always occurs during power running. It is necessary to install a direct current circuit breaker 19 having a large capacity capable of passing an electric current, and there is also a problem that a loss occurs due to a contact resistance of the direct current circuit breaker 19. The present invention has been made in view of the above-described circumstances, and an object of the first to fourth inventions is to provide a thyristor DC power supply device having a good power supply power factor during power running operation. It is an object of the fifth and sixth inventions to provide a thyristor DC power supply device capable of protecting only a regenerative side thyristor reverse converter, which requires protection of the thyristor from the polarity of the load, from overcurrent.

[0011]

A thyristor DC power supply device according to the first invention is a thyristor forward converter for converting AC power from a power supply into DC power and applying it to a load, and regenerative power from the load into AC power. A thyristor reverse converter for converting, a step-up transformer for boosting the AC power converted by the thyristor reverse converter and returning it to the power source, and a switching control for performing switching control of the thyristor forward converter and the thyristor reverse converter. Unit, a DC voltage detector that detects the voltage of the DC power and the regenerative power converted by the thyristor forward converter, a DC current detector that detects the current of the DC power and the regenerative power, the DC power and A setter that sets the voltage value of the regenerative power, and the DC power generator that reduces the difference between the voltage value set by the setter and the voltage value detected by the DC voltage detector. And a voltage control unit that outputs a current instruction value for controlling the current of the regenerative power, and a difference between the current instruction value output by the voltage control unit and the current value detected by the DC current detector is reduced. The thyristor forward converter and the current control unit for controlling the phase of the thyristor inverse converter are provided.

A thyristor DC power supply device according to a second aspect of the present invention includes a step-down transformer for stepping down AC power from a power source, and a thyristor forward converter for converting the AC power stepped down by the step-down transformer into DC power and applying it to a load. A thyristor reverse converter that converts regenerative electric power from the load into AC power and returns it to the power source; a switching control unit that controls switching of the thyristor forward converter and the thyristor reverse converter; and the thyristor forward converter. A DC voltage detector that detects the converted DC power and the voltage of the regenerative power, a DC current detector that detects the current of the DC power and the regenerative power, and set the voltage values of the DC power and the regenerative power. And the current of the DC power and the regenerative power so that the difference between the voltage value set by the setting device and the voltage value detected by the DC voltage detector becomes small. A voltage control unit for outputting a current instruction value for controlling, and the thyristor forward converter and the aforesaid thyristor forward converter so that the difference between the current instruction value output by the voltage control unit and the current value detected by the DC current detector becomes small. And a current control unit that controls the phase of the thyristor inverse converter.

In the thyristor DC power supply device according to the third aspect of the present invention, the switching controller smoothly operates the thyristor forward converter and the thyristor inverse converter regardless of the difference between the voltage of the AC power from the power supply and the voltage boosted by the step-up transformer. It is characterized in that it comprises means for controlling the phase of the thyristor forward converter or the thyristor inverse converter in order to switch to.

In the thyristor DC power supply device according to the fourth aspect of the present invention, the switching control unit is configured so that the thyristor forward converter and the thyristor inverse converter have a difference between the voltage of the AC power from the power source and the voltage of the AC power converted by the thyristor inverse converter. In order to switch smoothly regardless of the above, a means for controlling the phase of the thyristor forward converter or the thyristor inverse converter is provided.

The thyristor DC power supply device according to the fifth aspect of the invention is characterized in that the thyristor reverse converter has a DC circuit breaker and is designed to protect only the thyristor of the thyristor reverse converter.

The thyristor DC power supply device according to the sixth aspect of the invention further comprises an overcurrent detector for detecting an overcurrent of the current detected by the DC current detector, and the thyristor reverse converter is provided between the thyristor forward converter and the load. Has a semiconductor valve,
The semiconductor valve is turned off when the overcurrent detector detects an overcurrent, and is designed to protect only the thyristor included in the thyristor reverse converter.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the drawings showing the embodiments thereof. Embodiment 1. FIG. 1 is a block diagram showing a configuration of an embodiment of a thyristor DC power supply device according to the present invention. In this thyristor DC power supply device, three pairs of series-connected diode pairs 1a-1b, 1c-1d, 1e-1f are connected in parallel, and a power supply (not shown) is provided at each connection point of each pair.
Thyristor forward converter 1 (power running side converter) to which each phase power of the three-phase AC power from is supplied, and thyristor reverse conversion connected to this thyristor forward converter 1 via DC breaker 3 in anti-parallel 2 (regeneration side converter).

The thyristor inverse converter 2 includes three sets of diode pairs 2a-2b, 2c-2d, 2e-2 connected in series.
f are connected in parallel, and each phase power line of three-phase AC power is connected to each connection point of each pair. The respective phase power lines are connected to the respective phase power lines of the power source via the step-up transformer 14.

In addition, this thyristor DC power supply device has an inverter 5 having a smoothing capacitor 5a as a load.
Is connected to the thyristor forward converter 1, and a DC reactor 4 for smoothing the output current to the inverter 5, and a DC voltage detector for detecting the output voltage to the inverter 5 and the voltage of the regenerative power from the inverter 5 are connected. 6 and inverter 5
A DC current detector 7 for detecting an output current to the inverter 5 and a current of regenerative power from the inverter 5, and a setter 8 for setting an output voltage value to the inverter 5 and a voltage value of regenerative power from the inverter 5. A current instruction value for controlling the output current to the inverter 5 and the current of regenerative power from the inverter 5 so that the difference between the voltage value set by the setter 8 and the voltage value detected by the DC voltage detector 6 becomes small. And a voltage control section 9 for outputting.

In addition, this thyristor DC power supply device has a DC current detector 7 and a current instruction value output by the voltage control unit 9.
The current control unit 10 that controls the phase of the thyristor forward converter 1 and the thyristor inverse converter 2 so that the difference between the detected current values becomes small, and the thyristor forward converter 1 and the thyristor according to an instruction from the current control unit 10. A gate pulse control unit 11 that switches the inverse converter 2 and determines the phase of each pulse to each gate of the thyristors 1a to 1f and 2a to 2f of the thyristor forward converter 1 and the thyristor inverse converter 2.
And a gate pulse generator 12 for driving the thyristor forward converter 1 and the thyristor inverse converter 2 by respectively outputting gate pulses in response to an instruction from the gate pulse control unit 11.
And a gate pulse generator 13. The gate pulse control unit 11 performs switching according to the direction of the current detected by the DC current detector 7, which is determined by the current control unit 10.

The operation of the thyristor DC power supply device having such a configuration will be described below. In this thyristor DC power supply device, the thyristor forward converter 1 is driven by the gate pulse generator 12 to rectify the three-phase AC power from the power supply. The rectified DC power is smoothed by the DC reactor 4 and given to the inverter 5. In the inverter 5, the DC power is smoothed by the smoothing capacitor 5a and then converted into AC power of a predetermined frequency to drive a load such as an electric motor (not shown).

At this time, the voltage controller 9 controls the output current to the inverter 5 so that the difference between the voltage value set by the setter 8 and the voltage value detected by the DC voltage detector 6 becomes small. Outputs the current instruction value. The current control unit 10 is
Phase control of the thyristor forward converter 1 is performed so that the difference between the current instruction value and the current value detected by the DC current detector 7 becomes small. The gate pulse control unit 11 includes the current control unit 10
The phase of each pulse to each gate of the thyristors 1a to 1f of the thyristor forward converter 1 is determined according to the instruction from the gate pulse generator 12, and the gate pulse generator 12 outputs the gate pulse according to the instruction from the gate pulse control unit 11. Then, the thyristor forward converter 1 is driven.

When regenerative electric power is generated by regenerative braking of the electric motor which is a load and a current flows backward, the current control unit 10
Is to determine the reverse flow based on the current value detected by the DC current detector 7, and the gate pulse control unit 11 switches from the gate pulse generator 12 to the gate pulse generator 13 according to the determination. As a result, the thyristor forward converter 1 is stopped and the thyristor inverse converter 2 is driven.
At this time, the voltage control unit 9 controls the current of the regenerative power from the inverter 5 so that the difference between the voltage value set by the setting unit 8 and the voltage value detected by the DC voltage detector 6 becomes small. Output the indicated value. The current controller 10 controls the phase of the thyristor inverse converter 2 so that the difference between the current instruction value and the current value detected by the direct current detector 7 becomes small.

The gate pulse controller 11 is the current controller 1
By the instruction from 0, the phase of each pulse to each gate of the thyristors 2a to 2f of the thyristor inverse converter 2 is determined,
The gate pulse generator 13 outputs a gate pulse according to an instruction from the gate pulse control unit 11 to drive the thyristor inverse converter 2. As a result, the thyristor reverse converter 2 converts the regenerative power into the three-phase AC power having the same frequency as the three-phase AC power from the power supply. Step-up transformer 14
The three-phase AC power converted by the thyristor reverse converter 2 is boosted by a predetermined transformation ratio and returned to the power supply.

The DC circuit breaker 3 is activated when the thyristor reverse converter 2 is driven, and when the current of regenerative power from the inverter 5 to the thyristor reverse converter 2 exceeds a predetermined value and becomes excessive, cuts off the current. Then, the thyristor elements 2a to 2f of the thyristor inverse converter 2 are protected. As a result, current does not flow in the DC circuit breaker 3 during power running, and loss due to contact resistance is reduced. Further, the amount of current flowing in the regenerative circuit of the thyristor reverse converter 2 and the step-up transformer 14 and the thyristor forward converter 1
In the case of the thyristor DC power supply device in which the amount of current flowing in the power running circuit is different and the capacity of the regenerative circuit is small, the capacity of the DC circuit breaker 3 can be reduced according to the capacity of the regenerative circuit, and the thyristor elements 1a to Even if the ratings of 1f and 2a to 2f are different on the power running side and the regeneration side, it is possible to protect the regeneration side thyristor elements 2a to 2f in accordance with the ratings.

Here, the relationship between the input AC voltage effective value Vin of the thyristor forward converter 1, the output DC voltage Vdc, and the phase control angle α for controlling the thyristor is expressed by equation (1). Vdc = 1.35 × Vin × cosα (1) On the other hand, the power source power factor PF is represented by PF = cosα. For example, the commutation allowance angle of the regenerative side thyristor inverse converter 2 is set to 30.
When the temperature is secured, the power factor of the thyristor forward converter 1 on the power running side becomes cos 30 ° = 0.866. Therefore, the voltage of the regenerative power is 1 / cos 30 in the step-up transformer 14.
If the pressure is increased to 1.degree., The commutation margin angle during regeneration can be secured even if the phase control angle .alpha. = 0.degree. Of the thyristor forward converter 1. Therefore, in this thyristor DC power supply device, the power supply power factor during power running is cos 0 ° = 1.0
It becomes possible to drive as.

For example, in a power source in which a momentary power source voltage drop occurs, when a margin for the power source voltage drop is further taken as the phase control angle, a step-up transformer for boosting the voltage of the regenerative power returned from the thyristor inverse converter 2. By increasing the step-up ratio of the device 14, it becomes possible to maintain the power source power factor during power running in a high state, and stable regenerative operation becomes possible.

Further, the gate pulse control unit 11 switches the gate pulse generator 12 and the gate pulse generator 13 according to the judgment of the current control unit 10. At this time, the value of the phase control angle immediately after the switching is set. To do. In this thyristor DC power supply device, for example, when the phase control angle α = 0 ° of the thyristor forward converter 1 during power running is switched to the thyristor inverse converter 2 on the regeneration side, the initial value of the phase control angle becomes 30 °. . This value can be calculated by modifying the equation (1).

The input voltage Ving of the thyristor forward converter 1 on the power running side and the input voltage Vin of the thyristor reverse converter 2 on the regeneration side.
From r and the voltage value Vdc detected by the DC voltage detector 6, the phase control angle αing of the powering side thyristor forward converter 1 and the phase control angle αinr of the regenerative side thyristor inverse converter 2 are
It can be calculated by the equations (2) and (3). αing = cos ⁻¹ (Vdc / (1.35 × Ving)) (2) αinr = cos ⁻¹ (Vdc / (1.35 × Vinr)) (3) Gate pulse generator 12 and gate pulse generator 13
Is a power supply voltage input to the thyristor forward converter 1 by outputting the first gate pulse according to αing and αinr calculated by these relational expressions, respectively,
Even if the voltage of the regenerative power returned from the thyristor inverse converter 2 to the power supply is different, the thyristor forward converter 1 and the thyristor inverse converter 2 can be switched smoothly.

FIG. 2 shows that when the gate pulse control unit 11 switches the gate pulse generator 12 and the gate pulse generator 13, and the thyristor forward converter 1 and the thyristor inverse converter 2 are switched. 6 is a flowchart showing the operation of the pulse control unit 11. The operation of the gate pulse controller 11 will be described below with reference to this flowchart. When the current control unit 10 determines that the current flowing direction is reversed by the current value detected by the DC current detector 7 and the switching condition is satisfied (S1
0), the gate pulse control unit 11 reads the voltage value detected by the DC voltage detector 6 (S12).

When the gate pulse control unit 11 switches to the gate pulse generator 12 which drives the thyristor forward converter 1 (power running side converter) (S14), the power running side phase control angle initial value αing is changed to αing. = Cos ^-1 (Vdc
/(1.35.times.Ving)) (S16) and gives it to the gate pulse generator 12 (S18). The gate pulse generator 12 drives the thyristor forward converter 1 according to the given phase control angle initial value αing.

When the gate pulse control section 11 switches to the gate pulse generator 13 for driving the thyristor inverse converter 2 (regeneration side converter) (S14), the regeneration side phase control angle initial value αinr is set to αinr. = Cos ^-1 (Vdc
/(1.35×Vinr)) (S20), and gives it to the gate pulse generator 13 (S18). The gate pulse generator 13 drives the thyristor inverse converter 2 according to the given phase control angle initial value αing.

Embodiment 2. FIG. 3 is a block diagram showing the configuration of an embodiment of the thyristor DC power supply device according to the present invention. This thyristor DC power supply device has the same configuration as that of the thyristor DC power supply device according to the embodiment of the present invention described in Embodiment 1 (FIG. 1), except that the semiconductor valve 15 is connected instead of the DC circuit breaker 3. An overcurrent detector 16 for detecting an overcurrent of the current detected by the current detector 7 is provided. The semiconductor valve 15 is turned off when the overcurrent detector 16 detects an overcurrent, and the thyristor reverse converter 2
Protects only the thyristors 2a to 2f possessed by. Other configurations and operations are the same as the configurations and operations of the thyristor DC power supply device according to the present invention described in the first embodiment, and therefore description thereof is omitted.

Embodiment 3. FIG. 4 is a block diagram showing the configuration of an embodiment of the thyristor DC power supply device according to the present invention. This thyristor DC power supply device reduces the AC power from the power supply in place of the step-up transformer 14 in the configuration (FIG. 1) of the embodiment of the thyristor DC power supply device according to the present invention described in the first embodiment. A step-down transformer 17 provided to the thyristor forward converter 1 is provided.

The gate pulse control unit 11 smoothly operates the thyristor forward converter 1 and the thyristor inverse converter 2 regardless of the difference between the voltage of the AC power from the power source and the voltage of the AC power converted by the thyristor inverse converter 2. In order to switch, the thyristor forward converter 1 or the thyristor inverse converter 2 is phase-controlled. Other configurations and operations are the same as the configurations and operations of the thyristor DC power supply device according to the present invention described in the first embodiment, and therefore description thereof is omitted. Although the load is the smoothing capacitor 5a in the above-described embodiments,
As shown in FIG. 5, it is also possible to connect to a fixed polarity load 18 such that the output voltage polarity of the thyristor forward converter 1 does not become negative like the smoothing capacitor 5a.

[0036]

According to the thyristor DC power supply device of the first aspect of the invention, the thyristor forward converter converts the AC power from the power supply into DC power and gives it to the load, and the thyristor reverse converter converts the regenerative power from the load to AC. After being converted into electric power, the step-up transformer steps up the converted AC power and returns it to the power source, and the switching control unit controls switching between the thyristor forward converter and the thyristor reverse converter. The setter sets the voltage values of the DC power and the regenerative power, and the voltage control unit controls the currents of the DC power and the regenerative power so that the difference between the set voltage value and the voltage value detected by the DC voltage detector becomes small. Outputs the current instruction value for controlling. The current control unit performs phase control of the thyristor forward converter and the thyristor inverse converter so that the difference between the output current instruction value and the current value detected by the DC current detector becomes small.

As a result, the voltage of the regenerative electric power returned from the regenerative-side thyristor reverse converter to the power supply can be made higher than the power-supply voltage input to the power-running thyristor forward converter, so that a high power factor is achieved during power-running operation. Further, by increasing the voltage difference, stable regenerative operation becomes possible even if an instantaneous power supply voltage drop occurs.

In the thyristor DC power supply device according to the second aspect of the invention, the step-down transformer steps down the AC power from the power source, and the thyristor forward converter converts the stepped-down AC power to DC power and supplies it to the load. The inverse converter converts the regenerative electric power from the load to AC power and returns it to the power source, and the switching control unit controls the switching of the thyristor forward converter and the thyristor inverse converter. The setter sets the voltage values of the DC power and the regenerative power, and the voltage control unit controls the currents of the DC power and the regenerative power so that the difference between the set voltage value and the voltage value detected by the DC voltage detector becomes small. Outputs the current instruction value for controlling. The current control unit performs phase control of the thyristor forward converter and the thyristor inverse converter so that the difference between the output current instruction value and the current value detected by the DC current detector becomes small.

As a result, the voltage of the regenerative power returned from the regenerative thyristor reverse converter to the power supply can be made higher than the power supply voltage input to the power running side thyristor forward converter, so that a high power factor is achieved during power running operation. Further, by increasing the voltage difference, stable regenerative operation becomes possible even if an instantaneous power supply voltage drop occurs.

According to the thyristor DC power supply device of the third invention, in the switching control unit, the phase control means includes the thyristor forward converter and the thyristor inverse converter, and the AC power voltage from the power source and the step-up transformer. Since the thyristor forward converter or the thyristor inverse converter is phase-controlled so as to smoothly switch regardless of the difference in the boosted voltage, it goes without saying that the thyristor forward converter and the thyristor inverse converter can be smoothly switched. That is, the voltage of the regenerative power returned from the thyristor reverse converter on the regeneration side to the power supply can be made higher than the power supply voltage input to the thyristor forward converter on the powering side, and a high power factor can be obtained during powering operation. . Furthermore, by increasing the voltage difference, stable regenerative operation becomes possible even when an instantaneous power supply voltage drop occurs.

In the thyristor DC power supply device according to the fourth aspect of the present invention, in the switching control unit, the means for controlling the phase includes the thyristor forward converter and the thyristor inverse converter, the voltage of the AC power from the power source and the thyristor inverse converter. The thyristor forward converter or the thyristor inverse converter is phase-controlled so that the thyristor forward converter or the thyristor inverse converter can be smoothly switched regardless of the voltage difference of the converted AC power, so that the thyristor forward converter and the thyristor inverse converter can be smoothly switched. Of course, the voltage of the regenerative power returned from the thyristor reverse converter on the regenerative side to the power supply can be made higher than the power supply voltage input to the thyristor forward converter on the power running side, resulting in a high power factor during power running. Obtainable. Furthermore, by increasing the voltage difference, stable regenerative operation becomes possible even when an instantaneous power supply voltage drop occurs.

In the thyristor DC power supply device according to the fifth aspect of the invention, the thyristor reverse converter has a DC circuit breaker and is designed to protect only the thyristor of the thyristor reverse converter. It is possible to easily protect only the regenerative-side thyristor reverse converter on the regeneration side from overcurrent, and a small-capacity DC circuit breaker is sufficient, so that the cost of parts can be suppressed.

According to the thyristor DC power supply device of the sixth invention, when the overcurrent detector detects an overcurrent of the current detected by the DC current detector, the semiconductor valve is turned off and the thyristor reverse converter is activated. Protect only the thyristors you have. This makes it possible to easily protect only the regenerative thyristor inverse converter on the regeneration side, which requires protection of the thyristor due to the polarity of the load, from overcurrent, and also to reduce the cost of parts.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a thyristor DC power supply device according to the present invention.

FIG. 2 is a flowchart showing the operation of a gate pulse control unit.

FIG. 3 is a block diagram showing a configuration of an embodiment of a thyristor DC power supply device according to the present invention.

FIG. 4 is a block diagram showing a configuration of an embodiment of a thyristor DC power supply device according to the present invention.

FIG. 5 is a block diagram showing a configuration of an embodiment of a thyristor DC power supply device according to the present invention.

FIG. 6 is a block diagram showing a configuration example of a conventional thyristor DC power supply device.

[Explanation of symbols]

1 Thyristor forward converter, 2 Thyristor inverse converter, 3
DC breaker, 5 inverters, 6 DC voltage detector,
7 DC current detector, 8 setting device, 9 voltage control unit, 1
0 current control unit, 11 gate pulse control unit (switching control unit), 12, 13 gate pulse generator, 14 step-up transformer, 15 semiconductor valve, 16 overcurrent detector, 17
Step-down transformer, 18-polar fixed load.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02M 7/757 H02M 1/08 H02M 7/162 H03K 17/30 H03K 17/693

Claims (6)

(57) [Claims] 1. A thyristor forward converter for converting AC power from a power source into DC power and applying it to a load, a thyristor inverse converter for converting regenerative power from the load into AC power, and the thyristor inverse converter. A step-up transformer that steps up the AC power and returns it to the power source, a switching control unit that controls switching of the thyristor forward converter and the thyristor reverse converter, and DC power converted by the thyristor forward converter and the A DC voltage detector that detects the voltage of regenerative power,
A DC current detector that detects the current of the DC power and the regenerative power, a setter that sets the voltage value of the DC power and the regenerative power, a voltage value set by the setter and the DC voltage detector. A voltage control unit that outputs a current instruction value for controlling the currents of the DC power and the regenerative power so that the difference between the detected voltage values becomes small, and the current instruction value and the DC current output by the voltage control unit. A thyristor DC power supply device comprising: a current control unit that performs phase control of the thyristor forward converter and the thyristor inverse converter so that a difference between current values detected by a detector becomes small. 2. A step-down transformer for stepping down AC power from a power source, a thyristor forward converter for converting the AC power stepped down by the step-down transformer to DC power and applying it to a load, and regenerative power from the load to AC. A thyristor reverse converter that converts to electric power and returns to the power source, and a switching control unit that performs switching control of the thyristor forward converter and the thyristor reverse converter,
A DC voltage detector that detects the voltage of the DC power and the regenerative power converted by the thyristor forward converter, a DC current detector that detects the current of the DC power and the regenerative power, the DC power and the regenerative power. For controlling the current of the DC power and the regenerative power so that the difference between the voltage value set by the setter and the voltage value detected by the DC voltage detector becomes small. A voltage control unit that outputs a current instruction value, and the thyristor forward converter and the thyristor inverse converter so that the difference between the current instruction value output by the voltage control unit and the current value detected by the DC current detector becomes small. A thyristor DC power supply device, comprising: 3. The thyristor forward converter or the thyristor forward converter to smoothly switch the thyristor forward converter and the thyristor inverse converter regardless of the difference between the voltage of the AC power from the power source and the voltage boosted by the step-up transformer. The thyristor DC power supply device according to claim 1, further comprising means for controlling a phase of the thyristor inverse converter. 4. The thyristor is configured to switch smoothly between the thyristor forward converter and the thyristor inverse converter regardless of the difference between the voltage of the AC power from the power source and the voltage of the AC power converted by the thyristor inverse converter. 3. A means for controlling the phase of a forward converter or a thyristor inverse converter.
The thyristor DC power supply device described. 5. The thyristor DC power supply device according to claim 1, wherein the thyristor reverse converter has a DC circuit breaker and is designed to protect only the thyristor included in the thyristor reverse converter. 6. The semiconductor device further comprises an overcurrent detector for detecting an overcurrent of the current detected by the direct current detector, wherein the thyristor reverse converter has a semiconductor valve between the thyristor forward converter and the load. The thyristor DC power supply device according to any one of claims 1 to 4, wherein the valve is turned off when the overcurrent detector detects an overcurrent and protects only the thyristor included in the thyristor reverse converter.