WO2014030259A1

WO2014030259A1 - Voltage control apparatus

Info

Publication number: WO2014030259A1
Application number: PCT/JP2012/071488
Authority: WO
Inventors: 範久小林
Original assignee: Ｂｅｅｔｅｃｈ株式会社
Priority date: 2012-08-24
Filing date: 2012-08-24
Publication date: 2014-02-27

Abstract

Provided is a voltage control apparatus that can step up the voltage of an inputted polyphase alternating current and stably supply high voltage. The voltage control apparatus (10) is provided with: a zero-crossing detection means (20) that measures zero-crossing points of a three-phase AC voltage; a voltage adjustment means (50) that gives instructions to connect the phase in which a zero-crossing point is detected, phase T for example, to phase R having the same polarity as phase T; and an inter-phase connection means (60) that connects each of the phases with each other according to instructions from the voltage adjustment means (50). The voltage adjustment means (50) starts inter-phase connections from the zero-crossing points or from points in time obtained by shifting a phase angle from the zero-crossing points and determine the starting time, period length, and shift amount for inter-phase connection periods by executing PID control while monitoring the voltage measured by a voltage measurement means (30).

Description

Voltage control device

The present invention relates to a voltage control apparatus that performs multi-phase AC voltage control.

Although there are various methods for controlling the voltage of the polyphase alternating current, one described in Patent Document 1 is known as an example of a conventional voltage control device.
In Patent Document 1, when a zero-cross point of voltage is detected, an AC switch is turned on in synchronization with the zero-cross point to supply power to the load, and the output of the load current effective value integrating circuit is increased. There is described a cycle control device for the output power of an AC generator that turns off an AC switch when it is equal to or greater than a first threshold and then resumes power supply when an integral value is equal to or less than a second threshold.
In Patent Document 1, the output voltage of the generator is detected, and if the output voltage is equal to or lower than a predetermined reference voltage, the output of the conduction command is stopped and the AC switch is turned off. It is described that it is good.

JP 2003-199399 A

However, in Patent Document 1, an AC switch that uses a pair of thyristors connected in reverse parallel is an adjustment circuit that simply conducts or cuts off the supply of power. The voltage must be adjusted within a range in which the output voltage is reduced, and the output voltage is not further increased and supplied to the load. Therefore, there is a demand for a voltage control device that can boost the input multiphase AC voltage and stably supply a high voltage.

Therefore, an object of the present invention is to provide a voltage control device capable of boosting an input multiphase AC voltage and stably supplying a high voltage.

The voltage control device according to the present invention includes a zero-cross detection unit that measures a zero-cross point of a multiphase AC voltage, and one phase where the zero-cross point is detected by the zero-cross point as a reference phase, and has the same polarity as the one phase. A voltage adjusting means for instructing conduction between the reference phase and the to-be-conducted phase, and an interphase conducting means for conducting between the phases in accordance with an instruction from the voltage adjusting means. And
In the present invention, the voltage adjusting means instructs the interphase conduction means to conduct the phase between the reference phase and the conducted phase, thereby outputting the total voltage of the reference phase and the conducted phase.

The voltage adjustment means starts conduction between phases by the interphase conduction means from the zero-cross point of the reference phase within a period from the zero-cross point of the reference phase until the phase to be conducted has the same polarity as the reference phase. The conduction between the phases by the interphase conduction means can be started from a position where the phase angle is shifted from the zero cross point of the reference phase. By doing so, when the voltage to the load is insufficient, the phases can be conducted and boosted to a desired voltage.

In addition, a voltage measuring unit that measures a voltage obtained by rectifying the multi-phase alternating current is provided, and the voltage adjusting unit determines a period during which the phase conduction is performed based on the measured voltage from the voltage measuring unit and the set instruction voltage. By determining by control (proportional control (Proportional Control), integral control (Integral Control), differential control (Derivative Control)), a stable high voltage can be supplied to the load.

The interphase conduction means conducts the phase between the MOS transistors, and the voltage adjustment means indicates the interphase conduction to the gate of the MOS transistor as a switch signal. Therefore, the size can be reduced and the cost can be reduced.

According to the present invention, the total voltage of the reference phase and the conductive phase can be output within a period in which the conductive phase has the same polarity as that of the reference phase. Therefore, the input multiphase AC voltage is boosted. Thus, a high voltage can be stably supplied.

It is a figure which shows the structure of the voltage control apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the interphase conduction | electrical_connection means of the voltage control apparatus shown in FIG. 1, (A) is a figure which shows the switch circuit for electrically connecting between RS, (B) is the switch circuit for electrically connecting between ST. FIG. 2C is a diagram showing a switch circuit for conducting between RTs. It is a flowchart for demonstrating the voltage control method of the voltage adjustment means of the voltage control apparatus shown in FIG. (A) And (B) is a wave form chart for explaining adjustment of duty ratio of conduction between phases. It is a waveform diagram for explaining the adjustment of the phase angle of phase-to-phase conduction, (A) is a case where the phase-to-phase conduction period is within the period from the zero cross point of the reference phase until the phase to be conducted is the same polarity as the reference phase FIG. 5B is a waveform diagram showing a case where the phase angle is shifted beyond the zero-cross point of the phase to be conducted in the interphase conduction period. It is a figure which shows the voltage adjustment means to perform PID control.

DESCRIPTION OF SYMBOLS 10 Voltage control apparatus 20 Zero cross detection means 30 Voltage measurement means 40 Rotation measurement means 50 Voltage adjustment means 51 Subtractor 52 Operation part 53 Limiter 60 Interphase conduction means 61 Switch circuit D1 Diode N1, N2 nMOS transistor T1, T2 terminal R Resistance C Capacitor 70 Operation panel

A voltage control apparatus according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, in the present embodiment, a case will be described in which three-phase alternating current from the generator G is supplied to the load L via the rectifier RC.
The voltage control apparatus 10 includes a zero-cross detection unit 20, a voltage measurement unit 30, a rotation measurement unit 40, a voltage adjustment unit 50, an interphase conduction unit 60, and an operation panel 70.

The zero-cross detection means 20 detects a zero-cross point indicating when the T-phase alternating current passes through 0 V among the three phases, and notifies the voltage adjustment means 50 of the zero-cross point. In the present embodiment, the zero-cross point of the T phase is detected. However, the zero-cross points of all three phases may be detected in the R phase or the S phase. The zero cross detection means 20 can detect the zero cross point by a program operated by a computer by converting the AC voltage into digital data by AD conversion.

The voltage measuring means 30 measures a DC voltage obtained by rectifying the three-phase AC by the rectifier RC. This voltage measuring means 30 can use an AD converter, and is output to the voltage adjusting means 50 as digital data.
The rotation measuring means 40 has a function of notifying the voltage adjusting means 50 of a timing signal for measuring the rotation angle and speed of the rotor of the generator G. In this embodiment, a rotary encoder is used as the rotation measuring means 40, and a counter value is output as a timing signal.

The voltage adjustment means 50 conducts PID control based on the measured voltage from the voltage measurement means 30 and the set voltage input from the operation panel 70, thereby conducting a period in which the phases are conducted between the phases by the phase-to-phase conduction means 60 (below). This is referred to as the interphase conduction period.) And the voltage is adjusted. This conduction control is made to function by operating a voltage control program on a computer. In the present embodiment, the voltage adjusting unit 50 and the zero cross detecting unit 20 are separate blocks. However, whether or not the digital data from the AD converter of the zero cross detecting unit 20 indicates 0V is determined by the voltage. The detection function portion of the zero cross detection means 20 and the voltage adjustment means 50 may be integrally configured so that the zero cross point is detected by making a determination in the voltage control program operated by the adjustment means 50.

The interphase conduction means 60 has a function of individually conducting each of the R phase and the S phase, the S phase and the T phase, and the T phase and the R phase according to an instruction from the voltage adjustment means 50. The interphase conduction means 60 may be, for example, the circuit shown in FIG.

Here, an example of the interphase conduction means 60 will be described with reference to FIG.
The switch means 61 shown in FIGS. 2A to 2C is constituted by three identical switch circuits 61. FIG. 2 (A) is for conducting the R phase and the S phase, FIG. 2 (B) is for conducting the S phase and the T phase, and FIG. 2 (C) is a diagram illustrating the R phase and the T phase. Is made conductive. Since FIGS. 2A to 2C are the same as described above, only FIG. 2A will be described.

In the switch circuit 61, the terminal T1 connected to the R phase is connected to the drain (D) of the nMOS transistor N1. The source (S) of the nMOS transistor N1 is connected to the drain (D) of the nMOS transistor N2. The source (S) of the nMOS transistor N2 is connected to a terminal T2 connected to the S phase. The gates (G) of the nMOS transistors N1 and N2 are connected to a terminal that outputs an instruction (switch signal) of interphase conduction of the voltage adjusting means 50. The nMOS transistors N1 and N2 are turned on and off by this switch signal.

The switch circuit 61 further includes a resistor R and a diode D1 connected in parallel to each of the terminals T1 and T2, and a capacitor C connected in series to the resistor R and the diode D1. The connection point of the two capacitors C is connected to the connection point between the source of the nMOS transistor N1 and the drain of the nMOS transistor N2, and is connected to the frame ground of the generator G. Spike noise is removed by these resistor R, capacitor C, and diode D1.

Returning to FIG. 1, the operation panel 70 is used when a set voltage is input to the voltage adjusting means 50, and is formed of a keyboard and a display panel.
The generator G is a permanent magnet generator that generates a three-phase alternating current whose phases are shifted by 120 ° (2π / 3). The generator G can also be used as a Landell generator. The field rectifier RC is a three-phase bridge rectifier that outputs a direct current by full-wave rectifying a three-phase alternating current.

The operation and use state of the voltage control apparatus 10 according to the embodiment of the present invention configured as described above will be described with reference to the drawings. It is assumed that a desired voltage value (command voltage) has been input from the operation panel 70 in advance.

First, the voltage adjustment means 50 calculates the rotation speed of the generator G based on the timing signal from the rotation measurement means 40, and determines whether or not the rotation speed is equal to or greater than a predetermined value (step S10).
If the rotational speed of the generator G is greater than or equal to a predetermined value in step S10, the zero cross detection means 20 reads the T-phase voltage value and determines whether or not the zero cross point is reached (step S20). If it is not the zero cross point, the process proceeds to step S50.

If the zero-cross point is detected when the T-phase voltage value is monitored in step S20, the voltage adjusting means 50 measures the time after the zero-cross point is detected by the counter value of the rotation measuring means 40. The counter value is reset (step S30). Further, since the zero cross point is detected in step S20, the detection of the zero cross point by the zero cross detecting means 20 is stopped and the process proceeds to step S50 (step S40).
If the rotation speed of the generator G is less than the predetermined value in step S10, the interphase conduction means 60 is set in a non-operating state (open state) (step S70). Then, the process proceeds to step S50.

In step S50, reading of the counter value of the rotation measuring means 40 is started. Next, the voltage adjusting unit 50 reads the voltage value from the voltage measuring unit 30 (step S80).

Next, the voltage adjusting means 50 performs an operation for calculating the interphase conduction period. Here, the interphase conduction period will be described with reference to FIGS.
First, the conduction from the zero cross point, as shown in FIG. 4A, for example, if the T phase is a reference phase, the S phase, which is another phase having the same polarity as the T phase, is the conduction phase. Become. Conduction is performed within a period in which the T phase and the S phase have the same polarity. That is, the STs are electrically connected within a period from the zero cross point P1 at which the T phase becomes a positive voltage to the zero cross point P2 until the S phase becomes from a positive voltage to a negative voltage. Similarly, the RSs are electrically connected within a period from the zero cross point P2 at which the S phase becomes negative voltage to the zero cross point P3 until the R phase becomes from negative voltage to positive voltage. Further, the RTs are made to conduct in a period from the zero cross point P3 where the R phase becomes a positive voltage to the zero cross point P4 until the T phase becomes a positive voltage and a negative voltage.

In the next cycle, the ST is electrically connected during a period from the zero cross point P4 where the T phase becomes a negative voltage to the zero cross point P5 until the S phase changes from a negative voltage to a positive voltage. Further, the RSs are electrically connected within a period from the zero cross point P5 at which the S phase becomes a positive voltage to the zero cross point P6 until the R phase becomes a positive voltage to a negative voltage. Further, the RT is made to conduct in the period from the zero cross point P6 where the R phase becomes a negative voltage to the zero cross point P7 until the T phase becomes a positive voltage from the negative voltage.
In this way, the voltage adjusting means 50 first conducts the phases having the same polarity, so that the voltage of one phase and the voltage of the other phase are added and output to the rectifier RC. It becomes a state where a high voltage is output from the machine G.

This interphase conduction is a period (duty ratio) of a maximum of 16.67% for one conduction per cycle. This is because when the maximum conduction period is exceeded, the next interphase conduction timing overlaps. Therefore, it is necessary to suppress it to 16.67% or less at maximum in one conduction. Theoretically, however, the maximum conduction period of phase-to-phase conduction can be set between the start of the zero crossing point and 16.67%. It is desirable to shorten the duty ratio.

Therefore, as shown in FIG. 4B, in this embodiment, the maximum conduction period (first threshold) is set to about 12% (maximum duty ratio) per cycle in order to provide a margin. The maximum duty ratio can be appropriately adjusted according to the circuit configuration of the voltage control device 10, the program configuration that functions as the voltage adjusting means 50, the condition of the load L, and the like.

When the degree of boosting is insufficient at the maximum duty ratio, the voltage control device 10 shifts the phase angle while maintaining the width of the interphase conduction period in addition to the adjustment of the duty ratio. This phase angle shift will be described with reference to FIG.
As shown in FIG. 5A, the interphase conduction period is delayed from the zero cross points P1 to P6. When delaying the interphase conduction period, the conduction timing between the phases between RS, ST, and RT is similarly shifted. By doing so, as shown in FIG. 5B, even if the interphase conduction period exceeds the next zero cross point, there is no overlap with other interphase conduction timings. Therefore, the voltage control apparatus 10 can determine the shift of the phase angle of the interphase conduction period according to the degree of boosting.
By shifting the phase angle of the interphase conduction period in this way, the voltage of one phase and the voltage of the other phase are added, so that a high voltage can be output to the rectifier RC.

A control method of the voltage adjusting means 50 for adjusting the duty ratio and the phase angle in this way will be described with reference to FIG. First, the voltage adjusting means 50 calculates an output voltage for bringing the measurement voltage close to the command voltage. The voltage adjusting means 50 calculates the output voltage value by PID control.

In the voltage adjusting means 50, the subtractor 51 subtracts the measured voltage V 2 measured by the voltage measuring means 30 from the command voltage V 1 set by the operation panel 70. Then, an output voltage value is calculated by PID control by the calculation unit 52 from the difference between the command voltage V1 and the measured voltage V2. The limiter 53 sets the output voltage value as the upper limit value or the lower limit value when the output voltage value exceeds the upper limit value or the lower limit value. Then, it is output from the limiter 53 as the output voltage Vo.
In this way, the PID control is performed by negatively feeding back the measured voltage V2 in order to bring the output voltage Vo close to the command voltage V1, so that control with a small adjustment range of the voltage can be performed, so that a stable high voltage is supplied to the load L. can do.

When the output voltage Vo is thus calculated, the voltage adjusting means 50 determines the duty ratio and the phase angle according to the output voltage Vo. For example, when the instruction voltage V1 is 250V and the measurement voltage V2 is 150V, the voltage adjusting means 50 increases the voltage that increases by feeding back the measurement voltage V2 by PID control in order to boost the difference of 100V. While monitoring, the duty ratio for the interphase conduction period and the phase angle shift amount for shifting the interphase conduction period are determined (step S90).
The phase-to-phase conduction period can be adjusted based on the duty ratio for phase-to-phase conduction from the zero-cross point, or adjusted based on the phase angle by shifting the phase angle. If the desired voltage (indicated voltage V2) can be ensured only by the duty ratio adjustment. The adjustment based on the phase angle may not be performed or may be performed simultaneously.

Next, the voltage adjusting means 50 determines the half-phase timing of the T phase based on the timing signal from the rotation measuring means 40 read in step S50 (step S100). If it is the timing of the half cycle of the T phase in step S100, the timing of the R phase and the S phase at which the zero cross point occurs every 60 ° is calculated, and the respective zero cross points are calculated (step S110). ). As a result, the zero-cross point of each phase, which is a reference for the timing of conducting the interphase conduction to the interphase conduction means 60, is known. If the half-phase timing of the T phase cannot be determined from the timing signal from the rotation measuring means 40, each zero cross point cannot be calculated, and the process proceeds to step S130.

Next, from the duty ratio of the interphase conduction period calculated in step S90 and the phase angle shift for shifting the interphase conduction period, the actual time for starting the interphase conduction (interphase conduction start time) and the real time for ending the interphase conduction. By calculating (interphase conduction end time), the duty amount and the phase angle amount are determined (step S120).
Next, since the elapsed time from the zero cross point is determined from the counter value read in step S50, the current phase is in the interphase conduction period from the interphase conduction start time and the interphase conduction end time calculated in step S120. It is determined whether or not (step S130). If it is not during the interphase conduction period, the voltage adjusting means 50 outputs the switch signal OFF indicating the conduction release instruction to the switch circuit 61 (see FIG. 2), and returns to Step S10 (Step S140).

If it is determined in step S130 that the inter-phase conduction period is within, the voltage adjusting unit 50 outputs a conduction instruction (switch signal ON) to the switch circuit 61 of the inter-phase conduction unit 60 corresponding to the phase to be conducted ( Step S150).
When the switch signal of the voltage adjusting means 50 is turned on, the nMOS transistors N1 and N2 are turned on in the switch circuit 61 shown in FIG. 2, and a current flows between the terminals T1 and T2.

For example, if one phase connected to the terminal T1 has a higher voltage than the other phase connected to the terminal T2, a current flows from the terminal T1 to the terminal T2 via the nMOS transistors N1 and N2, and is connected to the terminal T2. If the other phase is higher in voltage than one phase connected to the terminal T1, a current flows from the terminal T2 to the terminal T1 through the nMOS transistors N2 and N1. As described above, since the MOS transistor is a symmetric element, by outputting a switch signal instructing conduction to the gate, the drain-source is made conductive regardless of whether the drain or source voltage is high. Can do.

In this way, the switch circuit 61 conducts the phases. Since the switch circuit 61 is configured by a MOS transistor, phase-to-phase conduction can be achieved with a simple circuit configuration, so that the size can be reduced and the cost can be reduced.
In the present embodiment, the switch circuit 61 is provided with a circuit for removing noise (diode D1, resistor R, capacitor C), but may be omitted. In that case, only one of the nMOS transistors N1 and N2 needs to be provided.
After conducting the interphase conduction, the process proceeds to step S10, and these processes are repeated.

As described above, according to the voltage control device according to the present embodiment, the phase is conducted from the zero cross point (adjustment by duty ratio), or the timing at which the phase is conducted from the zero cross point is shifted (adjustment by phase angle). Then, by outputting the added two-phase voltage added to the load L, a high voltage can be stably supplied to the load L.

As described above, in the embodiment of the present invention, three-phase alternating current has been described as an example. However, the present invention is not limited to a multi-phase alternating current that can be conducted in a period in which one phase and the other phase have the same polarity. The boosted voltage can be supplied to the load when applied.
Further, in the present embodiment, the example in which the three-phase alternating current from the generator G is boosted has been described, but another generation source may be used.

The voltage control device of the present invention can be applied as long as polyphase alternating current is used. In particular, the voltage control device of the present invention is suitable for installation in a facility or mounting in a refrigerator / refrigerator vehicle.

Claims

Zero-cross detection means for measuring the zero-cross point of the polyphase AC voltage;
The voltage indicating the conduction between the reference phase and the phase to be conducted, with the one phase where the zero cross point is detected as the reference phase and the other phase having the same polarity as the one phase as the conduction phase Adjustment means;
A voltage control apparatus comprising: interphase conduction means for conducting between the phases in accordance with an instruction from the voltage adjustment means.
The voltage adjusting means starts conduction between phases by the interphase conduction means from a zero cross point of a reference phase within a period from a zero cross point of the reference phase to a phase to be conducted having the same polarity as the reference phase. The voltage control apparatus as described.
The voltage control device according to claim 1 or 2, wherein the voltage adjusting means starts conduction between phases by the interphase conduction means from a position where a phase angle is shifted from a zero cross point of a reference phase.
A voltage measuring means for measuring a voltage obtained by rectifying the polyphase alternating current;
The voltage control device according to claim 1, wherein the voltage adjusting unit determines a period for conducting phase-to-phase based on a measured voltage from the voltage measuring unit and a set instruction voltage by PID control.
The interphase conduction means conducts the phase by a MOS transistor,
2. The voltage control apparatus according to claim 1, wherein the voltage adjusting means instructs the gate of the MOS transistor as a switch signal to conduct between phases.