JP3516601B2 - Converter circuit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This invention relates to AC power converter circuits to be supplied to the load is converted into direct current.

[0002]

2. Description of the Related Art FIG. 11 shows, for example, JP-A-10-11102.
It is a block diagram which shows the conventional converter circuit shown by the 8th publication. In the figure, 1 is an AC power source, 2 is a rectifier circuit, and 2
a, 2b, 2c and 2d are diodes that constitute the rectifying circuit 2, 3
Is a reactor, 4 is a reverse current blocking diode, 5 is a smoothing capacitor, and 6 is a load connected to both ends of the smoothing capacitor 5.

Reference numeral 7 is a switch means connected to the output side of the rectifier circuit 2 via the reactor 3, and reference numeral 8 is a converter control means for controlling opening / closing of the switch means 7. The switch means 7 is a switch for short-circuiting the reactor 3 to a power source and storing magnetic energy. By opening and closing the switch, the input current and the load input voltage can be controlled. A command for opening / closing the switch means 7 is generated and output by the converter control means 8. A circuit composed of the reactor 3, the switch means 7, and the reverse current blocking diode 4 is generally called a boost circuit, and boosts (the output voltage is higher than the input voltage).
It is used for output voltage control and input current control applications in the area.

Next, the operation will be described with reference to FIG. First, during normal operation without the switch means 7, the AC power from the AC power supply 1 is full-wave rectified by the rectifier circuit 2 and supplied to the smoothing capacitor 5 via the reactor 3 and the reverse current blocking diode 4 to be smoothed. The load 6 is supplied as DC power. Next, when the switch means 7 operates, the converter control means 8 outputs a control signal synchronized with the power supply voltage to the switch means 7, and when the control signal is at a high level, the switch means 7 is closed and the reactor. Current flows through 3. After that, when the control signal from the converter control means 8 becomes low level, the switch means 7 is opened, the magnetic energy accumulated in the reactor 3 is accumulated in the smoothing capacitor 5, and the DC voltage rises.

FIG. 12 shows the switch means 7 once every half cycle of the power supply.
However, by controlling the switch means 7 at such a timing, the conduction angle of the power supply current can be expanded, the power supply power factor can be improved, and the power supply harmonics can be reduced. Further, when the on (close) time of the switch means 7 is changed, magnetic energy is accumulated in the reactor 3 during the on period and is released to the direct current side during the off (open) period. The terminal voltage) is boosted higher than the voltage when the switching means 7 is not switched. This DC voltage can be changed by changing the pulse width of the control signal from the converter control means 8, but in general, due to the magnetic saturation characteristics of the reactor 3 and the current rating of the element used for the switch means 7, Generally, the voltage can be boosted only up to about 1.2 times the maximum value of the AC power supply voltage.

In the above example, the switch means 7 is opened and closed once every half cycle of the power source, but this can control the DC voltage and the input current even by high frequency switching by PWM (pulse width modulation). In that case, since the number of times of switching per power supply cycle is as large as several tens to several hundreds, the input power supply power factor can be almost 1, and the DC voltage can be more than twice the maximum value of the power supply voltage. -The controllability of the output voltage is improved. However, the power loss that occurs when the switch means 7 is turned on and turned off increases, and the current component flowing through the reactor 3 has a high frequency, so that the conversion efficiency decreases, such as the iron loss increases in a general-purpose reactor.

[0007]

The conventional converter circuit as described above, however, has the following problems. That is, when the maximum DC voltage desired by the load is about 2 to 3 times the effective value of the power supply voltage and high conversion efficiency is required, as in a converter for an air conditioner, for example, as described above, the magnetic saturation characteristics of the reactor and the switch are used. Due to the limitation of the current rating of the element used in the means, there is a problem that it cannot be realized because the boosting rate is about 1.2 times the maximum value of the AC power supply voltage. Further, when high-speed switching is used to realize the required step-up rate, as described above, the power loss generated at the time of opening / closing the switch means increases, and the current component flowing in the reactor becomes high frequency, so that it can be used for general purposes. In the reactor, there was a problem that the iron loss increased and, as a result, the conversion efficiency decreased. The present invention has been made to solve the above problems, and an object thereof is to <br/> providing converter circuits capable power conversion with high conversion efficiency even higher boosting rate.

[0008]

According to a first aspect of the present invention, there is provided a converter circuit including a reactor having one end connected to an AC power supply, and the other end of the reactor shorted to the AC power supply.
Switch means for opening, rectifying means for converting the voltage across the switch means into a DC voltage and supplying power to the load,
Switching means for switching the rectification means between a full-wave rectification mode and a voltage doubler rectification mode, and controlling the states of the switch means and the switching means based on the voltage or power of the load to obtain at least the voltage doubler rectification mode. To be
A certain number of stages of bus voltage including DC voltage up to DC voltage
And a resulting Ru control means pressure, the said switch means said Li
Both provided between one end of the actor and the AC power supply
It is a directional switch element .

[0009]

A converter circuit according to the invention of claim 2 is
In the invention of claim 1, the switch means is a plurality of switching elements provided between one end of the reactor and a DC side terminal of the rectifying means.

A converter circuit according to the invention of claim 3 is
A reactor whose one end is connected to an AC power source, a bidirectional switch element that short-circuits and opens the other end of the reactor and the AC power source, and a voltage that converts the voltage across the bidirectional switch element to a DC voltage for powering the load. A double voltage rectifying circuit for supplying the load, a full-wave rectifying circuit for converting the voltage across the bidirectional switch element into a DC voltage to supply power to the load, the double voltage rectifying circuit or the full-wave rectifying circuit. The switching means for selecting one of the two, the states of the bidirectional switch element and the switching means are controlled according to the voltage or the power of the load , and at least the direct voltage obtained by the voltage doubler rectifier circuit is obtained.
Bus voltage in a certain number of steps including DC voltage up to the flowing voltage
The is obtained a resulting Ru control means.

A converter circuit according to a fourth aspect of the invention is
A reactor connected to an AC power source, a full-wave rectifier circuit connected to the reactor and converting an AC voltage into a DC power to supply power to a load, and one AC side terminal and a DC side terminal of the full-wave rectifier circuit. A plurality of switching elements connected between, a plurality of voltage doubler rectifying capacitors, each of which is connected in series and whose end is connected to the DC side terminal of the full-wave rectifier circuit, and the AC of the full-wave rectifier circuit. Switching means for short-circuiting / opening between a terminal of the side terminals to which no switching element is connected and a connection point of the plurality of voltage doubler rectifying capacitors; and the switching element and the switching means based on the voltage or power of the load. Control the state of at least
Below the DC voltage obtained by the above voltage rectifying capacitor
Those having a resulting Ru controller bus voltage of a predetermined number of steps, including a DC voltage to the upper.

A converter circuit according to the invention of claim 5 is
In the invention of claim 3 or 4 , the rectifying element of the voltage doubler rectifying circuit also serves as the rectifying element of the full-wave rectifying circuit.

A converter circuit according to a sixth aspect of the present invention is
In the invention according to any one of claims 1 to 5 , the control means controls the switching means so as to select the double voltage rectification mode when the load voltage is high and the full-wave rectification mode when the load voltage is low.

A converter circuit according to a seventh aspect of the invention is
In the invention according to any one of claims 1 to 5 , the control means controls the switching means so that the power source power factor increases.

A converter circuit according to the invention of claim 8 is
In the invention according to any one of claims 1 to 5 , the control means controls the switching means so as to reduce a power supply harmonic current.

A converter circuit according to a ninth aspect of the invention is
In the invention of any one of claims 1 to 5, said control means, on SL as close a DC voltage to a voltage value required load
And controls the changeover means.

A converter circuit according to a tenth aspect of the present invention is the converter circuit according to any one of the first to eighth aspects, wherein the load is an inverter and a motor, and the full-wave rectification mode and the voltage doubler rectification mode in the control means. The selection is to select the full-wave rectification mode when the speed command value of the motor is small and the double voltage rectification mode when the speed command value is large.

According to an eleventh aspect of the present invention, in the converter circuit according to any one of the first to eighth aspects, the load is a DC motor, and the full-wave rectification mode and the voltage doubler rectification mode in the control means are used. In the selection, the full-wave rectification mode is selected when the speed command value of the DC motor is small, and the double voltage rectification mode is selected when the speed command value is large.

[0020]

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
It will be described with reference to the drawings. First Embodiment FIG. 1 is a configuration diagram showing a first embodiment of the present invention. Note that, in FIG. 1, portions corresponding to those in FIG. 11 are denoted by the same reference numerals, and duplicate description thereof will be omitted. In the figure, a reactor 3 is provided between an AC power supply 1 and a rectifier circuit 2. 9
Is connected between the other end of the reactor 3 (on the side of the rectifier circuit 2) and the AC power supply 1, and the bidirectional switch element 10a, 10b as a switch means for short-circuiting / opening the AC power supply 1 is connected in parallel to the smoothing capacitor 5. A connected double voltage rectifying capacitor, 11 is a switch inserted between the connecting point of the double voltage rectifying capacitors 10a and 10b and one end of the rectifying circuit 2 on the AC side, that is, a connecting point of the rectifying element, for example, the diodes 2b and 2d. A relay as a means, 12 is a converter control means for controlling the opening and closing of the bidirectional switch element 9 and the relay 11.
The rectifier circuit 2 and the double voltage rectifying capacitors 10a, 1
0b constitutes a rectifying means.

Next, the operation will be described. The operating state of this embodiment is bidirectional switch element 9 and relay 1.
Since the state 1 is different, the operation for each state will be described first, and then the overall operation will be described. Further, for convenience, the effective value of the power supply voltage of the AC power supply 1 is Vs, the instantaneous value is Vst,
The inductance of the reactor 3 is L, the resistance value is R, the terminal voltage of the smoothing capacitor 5 is Vdc, and the current flowing through the reactor 3 is i.

First, the case where the bidirectional switch element 9 is stopped (open) will be described. Here, when the relay 11 is open (hereinafter referred to as state I), the circuit operates as a full-wave rectifier circuit, and a bus voltage (terminal voltage of the smoothing capacitor 5) of about √2 × Vs is obtained. When the relay 11 is closed (hereinafter, referred to as state II), the circuit operates as a voltage doubler rectifier circuit and a bus voltage of about 2√2 × Vs is obtained.

Next, a case where the bidirectional switch element 9 is in operation (on / off is repeated) will be described. When the bidirectional switch element 9 is on, a short-circuit current flows through the AC power supply 1-reactor 3-bidirectional switch element 9, and current energy is accumulated in the reactor 3. When the bidirectional switch element 9 is turned off, the current energy accumulated in the reactor 3 is supplied to the smoothing capacitor 5 and the bus bar voltage rises. Here, when the relay 11 is open (hereinafter referred to as state III), the bus voltage is approximately √2 × Vs.
When the relay 11 is closed (hereinafter referred to as state IV), the bus voltage becomes a value of approximately 2√2 × Vs or more.

The states I to IV described above can generate independent voltage values. Therefore, if the converter control means 12 selects one of the states I to IV in accordance with the voltage value required by the load 6, a four-stage bus voltage can be easily obtained.

When the on-time ratio of the bidirectional switch element 9 in the states III and IV is increased, the amount of energy supplied to the smoothing capacitor 5 side is increased and the bus bar voltage is further increased. In other words, converter control means 12 can control the bus voltage in a stepless manner at √2 × Vs or more by operating the ON time ratio during operation in states III and IV.

FIG. 2 is a system configuration diagram for controlling the power supply current and the bus voltage, for example. In the figure, 1
Reference numeral 3 is a current detecting means which is inserted in a current path of the AC power supply 1 and detects an input current of the circuit, and 12a is input with a bus voltage Vdc which is a terminal voltage of the smoothing capacitor 5 and a command value Vdc ^* of a predetermined bus voltage. Bus voltage control means, 12b is connected to both ends of the AC power supply 1, voltage detection means for detecting a sinusoidal AC power supply voltage, 12c is a multiplier for multiplying the outputs of the bus voltage control means 12a and the voltage detection means 12b, 12d
Is a comparator for comparing the output of the current detecting means 13 and the output of the multiplier 12c and controlling the opening / closing of the bidirectional switch element 9 according to the comparison result.

Next, the general operation of this system will be described. The bus voltage control means 12a inputs the bus voltage Vdc and the command value Vdc ^* of the bus voltage, integrates the error value thereof, and outputs the error value. The multiplier 12c inputs the outputs of the bus voltage control means 12a and the voltage detection means 12b, multiplies them, and outputs them as a command value I ^* of the input current. The comparator 12d is a multiplier 12c
Of the current command value I ^* output from the current detection means 13 is compared, and if the current command value I ^* > the actual current value I, the bidirectional switch element 9 is closed, and the current command value I ^* <
If the actual current value is I, the control signal is output to open the bidirectional switch element 9. By continuously performing these operations, the input current approaches a sine wave, and the bus voltage V
dc reaches the command value Vdc ^* .

Here, as a means for outputting a voltage of 2√2 × Vs or more as a bus voltage, a method of performing the relay 11 in an open state (state III) and a relay 11 in a closed state (state I).
V) can be used. The difference in loss occurrence between state III and state IV will be described below, and the superiority of operation in state IV at high output voltage will be described. For convenience of explanation, the bidirectional switch element 9 is a PW.
It is opened and closed by M control, and its switching frequency is sufficiently higher than the power supply frequency.

First, the waveform of the current flowing through the reactor 3 in a predetermined PWM cycle is shown in FIG. In FIG.
The control signal is a PWM control signal for the bidirectional switch element 9, and indicates a switch-on (closed) at a high level and a switch-off (open) at a low level. The current flowing through the reactor 3 becomes a sawtooth current as shown in the figure, and when the current increases,
If de1 and mode2 are the current decrease times, the respective currents are expressed by the following equations (1) and (2).

[0031]

[Equation 1]

[0032]

[Equation 2]

Here, Vst is the input voltage of the voltage value of the AC power supply within the PWM cycle (corresponding to the portion of the converter (actually reactor 3, rectifying circuit 2, voltage doubler rectifying capacitors 10a and 10b, smoothing capacitor 5)). Equivalent to), Vo
Is the output voltage of the converter, t is the elapsed time from the start of the mode, and Io is the initial value of the current flowing through the reactor 3 at the start of the mode (t = 0). Mode2 as above
Is the difference V between the converter output voltage and the input voltage.
It is a function of o-Vst, and it can be seen that the larger the Vo-Vst, the smaller the second term on the right side of the equation (2). This means that the current change rate in mode 2 becomes large.

FIG. 4 shows the bus voltage, that is, the smoothing capacitor 5.
The waveform of the electric current which flows into the reactor 3 when the terminal voltage of is changed is shown. When Vo-Vst is increased under the condition that the average current is constant in the PWM cycle as shown in FIG.
The amount of current ripple (P
It can be seen that the current amplitude in the WM cycle) increases. on the other hand,
There is a positive correlation between the amount of current ripple and the iron loss of reactor 3, and as the current ripple increases, the loss of reactor 3 increases. That is, if the difference Vo-Vst between the output voltage and the input voltage of the converter is large, the conversion efficiency decreases.

In the case of the full-wave rectifier circuit (state III), since the output voltage Vo of the converter is charged in the smoothing capacitor 5, Vo = Vdc, but the voltage doubler rectifier circuit (state I).
In the case of V), either of the voltage doubler rectifying capacitors 10a and 10b is charged, so Vo <Vdc. That is, if Vdc and Vst are the same, Vo-Vst becomes smaller and the conversion efficiency becomes higher in the voltage doubler rectifier circuit.

From the above points, the converter control means 12 realizes a converter having a high conversion efficiency by controlling the relay 11 based on the bus voltage command value Vdc ^* desired by the load as shown in FIG. FIG. 5 is a flowchart showing a relay control sequence in converter control means 12. That is, first, the bus voltage command value Vdc desired by the load
^* Is input (step S1), and it is checked whether the value is 2√2 times or more of the power supply voltage value, that is, the power supply voltage effective value Vs (step S2). If the determination result is true, that is, if Vdc ^* ≧ 2√2Vs, the relay 11 is turned on (closed) (step S3) to form the voltage doubler rectifier circuit. If false, that is, if Vdc ^* <√2Vs, the relay is turned off (opened) (step S4) to form a full-wave rectification circuit.

In this case, it is assumed that the bus voltage when the voltage doubler rectifier circuit is selected is 2√2 times the power supply voltage value, but in reality, the diodes 2a to 2d and the reactor 3 are Since there is a voltage drop of 2 and the effect of the boosting effect due to the switching of the bidirectional switch element 9, the threshold value may be above or below the above value. Again 2
By providing three different thresholds, one having a larger value is for turning on the relay 11 as a switching means, and the other having a smaller value is for turning off, so that the switching means when the bus voltage command value fluctuates in the vicinity of the threshold value. It is possible to prevent the chattering.

In the above description, the bidirectional switch element 9 is described as an example in which PWM or high frequency switching is performed, but this is not necessarily the case, and for example, ON / OFF switching is performed once every half cycle of the power supply. It is possible to reduce the reactor loss even in such a case. Also, FIG.
In the case of the circuit example, the smoothing capacitor 5 can be functionally substituted by the voltage doubler rectifying capacitors 10a and 10b connected in parallel, that is, the smoothing capacitor 5 can be omitted.

Further, in the circuit of FIG. 1, except for the voltage doubler rectifying capacitors 10a and 10b, the relay 11 and a part of the converter control means 12 (control part of the relay 11), a conventional circuit is obtained. That is, the double voltage rectification capacitors 10a and 10b, the relay 11, and the converter control means 12
By providing a part of the above as an additional component, it is possible to easily increase the output of the circuit by adding it to the conventional circuit.

Embodiment 2. 6 is a block diagram showing a second embodiment of the present invention. In the figure, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and duplicate description thereof will be omitted.
In the present embodiment, the bidirectional switch element 9 in the first embodiment is replaced with a pair of switching elements that are connected in parallel to one phase of the rectifier circuit 2 and that use, for example, a transistor or a thyristor. . In FIG. 6, 14
a and 14b are a pair of switching elements as a switching means, and these switching elements 14a and 14b
b are respectively connected in parallel to the diodes 2a and 2c of the rectifier circuit 2, and the control signal from the converter control means 12 is applied to the gate thereof.

Next, the operation will be described. First, the converter control means 12 detects the polarity of the power supply voltage of the AC power supply 1. At this time, if the power supply voltage is positive (potential of one terminal a of AC power supply 1> potential of the other terminal b of AC power supply 1), switching element 14a is turned off and only switching element 14b is allowed to switch. In addition, the power supply voltage is negative (potential of one terminal a of the AC power supply 1 <AC power supply 1
Of the other terminal b) of the switching element 1
4b is turned off, and switching of only the switching element 14a is permitted. The form of switching is the same as in the first embodiment.
Similar to the above, it may be performed by PWM or the like.

The difference in the effect in comparison with the first embodiment is that the number of elements in the current path when the switching element 14a or 14b is closed (ON) can be reduced. When the bidirectional switch element 9 of the first embodiment is actually realized, it is realized by, for example, a circuit as shown in FIG. 7, that is, a bridge circuit 15 using a diode and a unidirectional switch element 16 using a transistor, for example. Therefore, when the unidirectional switch element 16 is closed, a voltage drop of two diodes occurs. on the other hand,
In the circuit shown in FIG. 6, when one of the switching elements 14a and 14b is closed, one diode is provided in the current path.
There is only one. That is, the circuit of this embodiment has higher conversion efficiency.

Embodiment 3. 8 is a configuration diagram showing a third embodiment of the present invention. In the figure, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and duplicate description thereof will be omitted.
In the figure, 17 is an inverter that is connected to both ends of the smoothing capacitor 5 and that converts a DC voltage obtained at both ends into an AC voltage, 18 is a motor driven by the inverter 17, and 19 is an inverter control for controlling the inverter 17. It is a means.

Next, the operation will be described. The inverter control means 19 inputs the speed command value f ^* of the motor 18,
A control signal is output to the inverter 17 so that the rotation speed of the motor 18 matches the speed command value f ^* . Inverter 17
Generates an AC voltage based on the control signal given from the inverter control means 19 to drive the motor 18. Also,
The converter control means 12 inputs the speed command value f ^* and calculates the bus voltage command value Vdc ^* (details will be described later), and the converter is described in the first embodiment based on the bus voltage command value Vdc ^* . Control by way. As a result, a DC voltage sufficient to rotate the motor 18 at the speed command value f ^* is obtained at the input side of the inverter 17, that is, at both ends of the smoothing capacitor 5, and this DC voltage is converted into an AC voltage by the inverter 17 And the motor 18 reaches the target speed.

As the bus voltage command value Vdc ^* in the converter control means 12, the minimum voltage value that allows the motor 18 to rotate at the command value speed and that the converter can output is selected. For example, the following method is used.

FIG. 9 is a sequence diagram showing an example of a bus voltage command value creating method. First, the speed command value f ^* is input (step S11), and the voltage value k · f ^* is obtained by multiplying the speed command value f ^* by a predetermined coefficient k (step S1).
2). Here, k is a coefficient based on the induced voltage constant of the motor, and when the motor rotation speed and the motor applied voltage are in a substantially proportional relationship, the minimum voltage at which the motor can be rotated at a predetermined rotation speed can be obtained. Next, the obtained voltage value k · f ^* is compared with a value that is √2 times the effective value Vs of the power supply voltage (step S1).
3), whichever is larger is output as the bus voltage command value Vdc ^* . That is, if k · f ^* ≧ √2Vs,
The voltage value k · f ^* is output as the bus voltage command value Vdc ^* (step S14), and if k · f ^* <2√2Vs, the bus voltage command value V is a value √2Vs that is √2 times the effective value of the power supply voltage.
It is output as dc ^* (step S15).

By controlling as described above, a proper bus voltage according to the number of rotations of the motor is supplied, and the bus voltage is not increased unnecessarily, so that the iron loss of the reactor and the motor iron loss are reduced. However, a highly efficient drive device can be obtained. Further, since the output of the motor can be increased as much as the circuit loss can be reduced, the maximum rotation speed of the motor can be increased. Although the converter control means 12 has been described above as calculating the bus voltage command value Vdc ^* , this is not necessarily the case, and the inverter control means 19 is not necessary.
May calculate the bus voltage command value Vdc ^* based on the sequence of FIG. 9, in which case the processing load on the converter control means 12 can be reduced.

Fourth Embodiment FIG. 10 is a configuration diagram showing a fourth embodiment of the present invention. In the figure, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and duplicate description thereof will be omitted. In the figure, reference numeral 20 denotes a DC motor connected to both ends of the smoothing capacitor 5 and driven by a DC voltage obtained across the both ends. The present embodiment substantially corresponds to a form in which the inverter and the motor of the above-mentioned third embodiment are replaced with a DC motor. Also in this case, as described above, the iron loss of the reactor 3 when the DC bus voltage is high can be reduced, so that the efficiency can be increased and the maximum rotation speed of the motor can be increased.

[0049]

As described above, according to the invention of claim 1, one end of which is connected to an AC power supply, a switch means for short-circuiting and opening the other end of the reactor and the AC power supply, Rectification means for converting the voltage across the switch means into a DC voltage to supply power to the load, switching means for switching the rectification means between a full-wave rectification mode and a voltage doubler rectification mode, and based on the voltage or power of the load. Control the states of the switching means and the switching means to reduce the
Both are above the DC voltage obtained by the voltage doubler rectification mode
And a resulting Ru controller bus voltage of a predetermined number of stages including a direct-current voltage of up to, the above switch means of said reactor one
Requires a bidirectional switch installed between the end and the AC power supply.
Since the original, it is possible to increase the converter efficiency at a direct current voltage is high This will allow for some power conversion with high conversion efficiency even higher boost ratio, also the switch means
Is installed between one end of the reactor and the AC power supply.
Efficient because it uses a stripped bidirectional switch element
There is an effect that Ru can power conversion.

[0050]

According to the second aspect of the invention, since the switch means is a plurality of switching elements provided between one end of the reactor and the DC side terminal of the rectifying means, efficient power conversion can be performed. There is an effect.

According to the invention of claim 3 , one end of which is connected to the AC power supply, and a bidirectional switch element for short-circuiting / opening the other end of the reactor and the AC power supply.
A voltage doubler rectifier circuit that converts the voltage across the bidirectional switch element into a DC voltage to supply power to the load, and a double voltage rectifier circuit that converts the voltage across the bidirectional switch element into a DC voltage to supply power to the load. and wave rectifier circuit, a switching means for selecting one of the voltage doubler rectifier circuit and the full-wave rectifier circuit, controls the state of the bidirectional switching element and the switching means in response to voltage or power of the load At least
Up to the DC voltage obtained by the voltage doubler rectifier circuit above
Since the bus voltage of a predetermined number of stages including a direct-current voltage and a resulting Ru control means, it is possible to obtain a state combined by, for example, 4 or more stages of the output voltage of the state of the switching means of the bidirectional switching element in a simple Moreover, there is an effect that the conversion efficiency can be increased in the state where the bus voltage is high.

According to the fourth aspect of the present invention, the reactor connected to the AC power source, the full-wave rectification circuit connected to the reactor for converting the AC voltage into DC and supplying the power to the load, and the full-wave rectification. A plurality of switching elements connected between one AC side terminal and a DC side terminal of the circuit, and a plurality of voltage doublers connected in series and having terminations connected to the DC side terminal of the full-wave rectifier circuit. A rectifying capacitor, switching means for short-circuiting / opening between a terminal to which no switching element is connected among the AC side terminals of the full-wave rectifying circuit, and a connection point of the plurality of voltage doubler rectifying capacitors, and the load. The state of the switching element and the switching means is controlled on the basis of voltage or power, and at least the voltage doubler rectification is performed.
DC voltage higher than the DC voltage obtained by the
Since a resulting Ru controller bus voltage of a predetermined number of stages including the pressure, there is an effect that it is possible to increase further the conversion efficiency than the invention of claim 3.

According to the invention of claim 5 , since the rectifying element of the voltage doubler rectifying circuit also serves as the rectifying element of the full-wave rectifying circuit, there is an effect that the number of elements constituting the device can be reduced. .

According to the sixth aspect of the present invention, the control means controls the switching means so as to select the double voltage rectification mode when the load voltage is high and the full-wave rectification mode when the load voltage is low. There is an effect that it is possible to prevent a decrease in conversion efficiency.

According to the invention of claim 7 , since the control means controls the switching means so that the power source power factor rises, the maximum output power can be improved and the conversion efficiency in that state can be improved. The effect is that it can be controlled to the maximum.

According to the invention of claim 8 , the control means controls the switching means so as to reduce the power supply harmonic current, so that the power supply harmonics can be suppressed and the conversion efficiency in that state can be suppressed. The effect is that it can be controlled to the maximum.

According to the ninth aspect of the present invention, the control means controls the device switching means so that the DC voltage approaches the voltage value required by the load, so that the output voltage can be controlled to a desired value and the state thereof can be maintained. There is an effect that the conversion efficiency in can be controlled to the maximum.

According to a tenth aspect of the present invention, the load is an inverter and a motor, and in the selection of the full-wave rectification mode and the voltage doubler rectification mode in the control means, a speed command value of the motor is small. When full-wave rectification mode is selected, and when it is large, voltage doubler rectification mode is selected, the conversion efficiency of the converter and the inverter that is the load can be controlled to the maximum, and the maximum rotation speed of the motor can be increased. There is.

According to the eleventh aspect of the present invention, the load is a DC motor, and the selection of the full-wave rectification mode and the voltage doubler rectification mode in the control means is such that the speed command value of the DC motor is small. When the full-wave rectification mode is selected and the voltage doubler rectification mode is selected when it is large, it is possible to reduce the loss of the motor and the converter and increase the maximum rotation speed of the motor.

[0061]

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a system configuration diagram when controlling a power supply current and a bus voltage.

FIG. 3 is a waveform diagram showing a reactor current in a predetermined PWM cycle.

FIG. 4 is a waveform diagram showing a reactor current when a bus voltage is changed.

FIG. 5 is a diagram showing a switching means control sequence in the converter control means.

FIG. 6 is a configuration diagram showing a second embodiment of the present invention.

FIG. 7 is a circuit diagram showing an example of an implementation form of a bidirectional switch element.

FIG. 8 is a configuration diagram showing a third embodiment of the present invention.

FIG. 9 is a diagram showing a bus voltage command value creation sequence.

FIG. 10 is a configuration diagram showing a fourth embodiment of the present invention.

FIG. 11 is a configuration diagram showing a conventional converter circuit.

FIG. 12 is a waveform diagram showing an input current / voltage of a conventional converter circuit.

[Explanation of symbols]

1 AC power supply, 2 rectifier circuit, 3 reactor,
5 smoothing capacitor, 6 load, 9 bidirectional switch element, 10a, 10b double voltage rectifying capacitor,
11 relays, 12 converter control means, 14
a, 14b switching element, 17 inverter,
18 motor, 19 inverter control means, 20
DC motor.

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Claims (11)

(57) [Claims] 1. A reactor having one end connected to an AC power supply, a switch means for short-circuiting / opening the other end of the reactor and the AC power supply, and a load for converting a voltage across the switch means into a DC voltage. Rectifying means for supplying electric power, switching means for switching the rectifying means between a full-wave rectification mode and a double voltage rectification mode, and controlling the states of the switching means and the switching means based on the voltage or power of the load , At least the above
DC up to or above the DC voltage obtained by the voltage rectification mode
And a resulting Ru controller bus voltage of a predetermined number of steps, including a voltage, said switching means on one end of the reactor
A bidirectional switch element provided between the AC power supply and
Converter circuit, characterized in that that. 2. The converter circuit according to claim 1, wherein the switch means is a plurality of switching elements provided between one end of the reactor and a DC side terminal of the rectifying means. 3. A reactor whose one end is connected to an AC power supply, a bidirectional switch element that short-circuits and opens the other end of the reactor and the AC power supply, and a voltage across both ends of the bidirectional switch element is converted to a DC voltage. And a double voltage rectifier circuit for supplying power to the load, a full-wave rectifier circuit for converting the voltage across the bidirectional switch element into a DC voltage and supplying power to the load, the double voltage rectifier circuit and the full voltage rectifier circuit, and Switching means for selecting one of the wave rectifier circuits, and controlling the states of the bidirectional switch element and the switching means in accordance with the voltage or power of the load , and at least
Direct voltage up to or above the DC voltage obtained by the voltage doubler rectifier circuit.
Converter circuit, characterized in that a resulting Ru controller bus voltage of a predetermined number of steps, including a flow voltage. 4. A reactor connected to an AC power source, a full-wave rectifier circuit connected to the reactor for converting an AC voltage into a DC power to supply power to a load, and one AC side terminal of the full-wave rectifier circuit. A plurality of switching elements connected between the DC side terminal and the DC side terminal; a plurality of voltage doubler rectifying capacitors each connected in series and having a terminal connected to the DC side terminal of the full-wave rectifier circuit; Switching means for short-circuiting / opening between a terminal to which no switching element is connected among the AC side terminals of the wave rectifier circuit and a connection point of the plurality of voltage doubler rectifying capacitors; and the switching based on the voltage or power of the load. Controlling the states of the element and the switching means , and at least the above
Do not exceed the DC voltage obtained by the double voltage rectifying capacitor.
Converter circuit, characterized in that a resulting Ru controller bus voltage of a predetermined number of stages including a direct-current voltage at. Rectifying device according to claim 5, wherein said voltage doubler rectifier circuit, the converter circuit according to claim 3 or 4 further characterized in that also serves as a rectifying element of the full-wave rectifier circuit. Wherein said control means, voltage doubler rectification mode when the voltage of the load is high, claim 1-5, characterized in that for controlling the switching means to select a full-wave rectification mode when low The converter circuit described in. 7. The control means controls the switching means so that a power source power factor increases.
The converter circuit according to any one of to 5 . 8. The control means, the converter circuit according to any one of claims 1 to 5, characterized in that for controlling the switching means so as to reduce power harmonic current. 9. The control means, the converter circuit according to any one of claims 1 to 5, characterized in that control over Symbol changeover means as close to the voltage value required DC voltage load. 10. The load is an inverter and a motor, and the selection of the full-wave rectification mode and the double-voltage rectification mode in the control means is such that when the speed command value of the motor is small, the full-wave rectification mode is large. converter circuit according to any one of claims 1-8, characterized by selecting the voltage doubler rectification mode when it is. 11. The load is a DC motor, and the selection of the full-wave rectification mode and the voltage doubler rectification mode in the control means is such that when the speed command value of the DC motor is small, the full-wave rectification mode is large. converter circuit according to any one of claims 1-8, characterized by selecting the voltage doubler rectification mode when it is.