WO2015136809A1 - Period detection mode control device and method - Google Patents

Abstract

Provided are a period and phase detection mode control device and method that make it possible to accurately detect the period and phase of various periodically varying input voltages having indeterminate voltages. The present invention is provided with an AC voltage sensor (12) for detecting an input voltage from a periodically varying voltage source (11) such as an AC power supply or a half-wave or full-wave rectified power supply; a maximum value and minimum value detection unit (13) for monitoring the input voltage for a prescribed period of time and acquiring a minimum input voltage value and a maximum input voltage value; and a period and phase detection processing unit (14) that selects, on the basis of the minimum input voltage value and maximum input voltage value detected by the maximum value and minimum value detection unit (13), at least one period detection mode from among a plurality of period detection modes for detecting the timing at which the input voltage crosses one of a plurality of different threshold voltages and detecting the period and phase of the input voltage, and uses the selected period detection mode to detect the period and phase of the input voltage.

Description

Period detection mode control apparatus and method

The present invention relates to a period detection mode control apparatus and method for controlling a detection mode for detecting a period of a periodic transition voltage such as an AC voltage.

In-vehicle chargers equipped with an AC-DC converter that generates a DC voltage from a cyclically shifted voltage, such as an AC voltage, perform PFC (power factor correction) control to improve the power factor, Rectified by a rectifier circuit, smoothed by a smoothing capacitor and converted into a DC voltage, the DC voltage is converted into a predetermined DC by a DC-DC converter, and finally supplied to a battery or the like.

In PFC control, a method of controlling the waveform of the input current so as to obtain a waveform similar to the waveform of the input voltage, or a sine wave map is provided in the microcontroller, and the waveform is adjusted according to the phase of the input voltage. A method of generating current along a sine wave map is used.

When a current is generated using a sine wave map, reading of the map is started at a phase of 0 degrees and 180 degrees of the input voltage, so that it is necessary to detect the phase of the input voltage. Therefore, it is necessary to correctly detect the timing at which the input voltage crosses 0 volts, that is, the zero cross.

Detecting the period of the input voltage is necessary for calculating the effective value of the input voltage, calculating the effective value of the current, and calculating the input power (average value). Based on the effective value of the input voltage, the effective value of the input current, and the input power (average value), the input current is controlled to be the target current in the current control mode of the AC-DC converter.

In such current control, when the cycle of the input voltage is disturbed and the cycle fluctuates, the effective value of voltage and current and power cannot be calculated correctly by calculation using a predetermined cycle value. In addition, the above target current update is performed in a half cycle (half wave) in order to quickly respond to the response value (following property) to the command value of the charging power commanded from the host device and the response property (following property) to the voltage fluctuation. ) Sometimes. Therefore, it is necessary to accurately detect the phase of the transition voltage of 0 degree or 180 degrees and accurately determine the update timing of the target current for each half cycle (half wave).

When the target current is updated at the phase of 0 ° or 180 ° of the transition voltage, that is, at the zero cross point, the current gradually changes from 0 amperes, so that a smooth current waveform can be obtained. On the other hand, when the input voltage is a voltage other than 0 volts, for example, near the peak voltage, if the target current is updated, the current near the peak current suddenly increases or decreases to the current after the change, so that the current waveform is greatly distorted. End up.

As a document related to the present invention, regarding the zero cross detection of an AC voltage, the following Patent Document 1 describes a configuration for setting a mask period (dead zone) for zero cross detection in order to prevent erroneous detection due to noise or the like. Yes. As shown in FIG. 9, the one described in Patent Document 1 detects whether the frequency of the AC voltage is 50 Hz or 60 Hz in the first predetermined period T1 from the start, and based on the detected frequency (1 / Detection frequency) / 2 to obtain a half cycle.

The detection of the frequency wave of the AC voltage in Patent Document 1 is 50 Hz if the number of zero crosses in the frequency measurement period T1 (for example, 200 ms) is 45 or more and 55 or less, and 60 Hz if the frequency is 56 or more and 65 or less. Then, from the maximum frequency fluctuation rate a of the AC voltage, the allowable fluctuation width α of the half cycle of the AC voltage is calculated as (1 / detection frequency) / 2 × a, and the mask period T2 is calculated as (1 / detection frequency) / Set as 2-α.

Then, the counter starts counting up every predetermined time with the timing of the zero cross of the AC voltage as a trigger, and the zero cross detected when the count value by the counter is a value within the mask period T2 is replaced with a regular zero cross of a half cycle. The zero cross detected after the lapse of the mask period T2 is detected as a regular zero cross of a half cycle.

In addition, when a noise pulse is mixed into a pulse train having a fixed period or when the pulse period of the pulse train fluctuates and the pulse period is shortened to a predetermined value or less, a pulse inhibit is performed to prevent the period shortening as follows. It is described in Patent Document 2.

Japanese Patent Laid-Open No. 11-318072 Japanese Patent Publication No.56-19767

The conventional zero-crossing detection method described in Patent Document 1 is based on the premise of phase detection with respect to a sine wave voltage having the same positive voltage and negative voltage, and provides a fixed mask period to prevent erroneous detection due to noise or the like. Although the zero cross of the AC voltage is detected, since the mask period is fixed, if the cycle of the input voltage fluctuates and fluctuates, a zero cross other than the regular zero cross of the cycle may be erroneously detected.

In addition, with respect to a generator voltage source to which a periodic transition voltage other than a sine wave voltage or a periodic transition voltage such as a full-wave rectification voltage or a rectangular wave voltage or a periodic transition voltage whose voltage is uncertain is input. In the zero-cross detection method, the period and the phase of 0 degree or 180 degrees cannot be accurately detected. In view of the above problems, an object of the present invention is to provide a period and phase detection mode control apparatus and method capable of accurately detecting the period and phase of various periodic transition voltages whose voltages are uncertain. To do.

In one embodiment of the period detection mode control device according to the present invention, the input voltage is monitored for a predetermined time, and a maximum value / minimum value detection means for acquiring a minimum value and a maximum value of the input voltage; The minimum value of the input voltage detected by the maximum / minimum value detection means from a plurality of period detection modes for detecting the timing and phase of the input voltage by detecting timing across any of different threshold voltages And at least one period detection mode based on the maximum value, and a period / phase detection processing means for detecting the period and phase of the input voltage in the selected period detection mode. .

The period / phase detection processing means selects one or a plurality of provisional period detection modes, detects the period and phase of the input voltage in the provisional period detection mode, and an error of the detected period is predetermined. Is determined to be within a predetermined reference range, and when it is within the predetermined reference range, one of the provisional cycle detection modes is determined as a cycle detection mode for detecting the cycle and phase of the input voltage. It is characterized by that.

According to the present invention, various input voltage waveforms can be obtained by selecting a period detection mode using an optimum threshold for period detection and detecting the period and phase based on the maximum value and the minimum value of the input voltage. On the other hand, it becomes possible to detect a more accurate cycle and phase.

Also, it becomes possible to further increase the voltage width and the type of waveform of the input voltage that can be used as an input voltage that can operate an apparatus such as an AC-DC converter. In addition, detection of a period necessary for PFC control can be performed in an optimum detection mode for input voltages other than a sine waveform.

It is a figure which shows the structural example to which the period detection mode control apparatus is applied. It is a figure which shows the flowchart of period detection mode control. It is a figure which shows the example of an aspect which acquires and hold | maintains the maximum value and minimum value of input voltage. It is a figure which shows 1st Embodiment of determination of the period detection mode based on the maximum value and minimum value of input voltage. It is a figure which shows 2nd Embodiment of selection of the period detection mode based on the minimum value and maximum value of an input voltage. It is a figure which shows an example of 1st period detection mode. It is a figure which shows an example of 2nd period detection mode. It is a figure which shows an example of 3rd period detection mode. It is a figure which shows the aspect of the detection of the conventional zero cross.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration example to which a cycle detection mode control apparatus according to the present invention is applied. As shown in the configuration example of FIG. 1, the periodic detection mode control device according to the present invention is an AC voltage sensor that detects an input voltage of a periodic shift voltage source 11 such as an AC power supply (system power supply) supplied from a commercial distribution network. 12, a maximum / minimum value detection unit 13 for detecting the maximum and minimum values of the input voltage detected by the AC voltage sensor 12, and a cycle / phase detection processing unit 14 for detecting the cycle and phase of the input voltage Is provided.

The period and phase detected by the period / phase detection processing unit 14 are notified to the AC / DC power conversion control unit 15. The AC / DC power conversion control unit 15 controls the input current and the like of the AC / DC power converter 16 based on the cycle and phase notified from the cycle / phase detection processing unit 14.

The period detection mode control device according to the present invention monitors the input voltage for a predetermined time, acquires the minimum value and maximum value of the input voltage, and detects the period and phase based on the minimum value and maximum value of the input voltage. By switching the, the cycle is detected by the optimum cycle detection mode corresponding to the waveform of the input voltage.

FIG. 2 shows a flowchart of cycle detection mode control. As shown in FIG. 2, the maximum value / minimum value detection unit 13 monitors the maximum value and the minimum value of the input voltage until the predetermined time of step S21 elapses, and acquires the maximum value and the minimum value of the input voltage. (Steps S21 and S22).

FIG. 3 shows an example in which the maximum value and the minimum value of the input voltage are acquired and held. FIG. 3A shows the input voltage. As shown in FIG. 3A, after the apparatus is started, the input voltage is monitored for a predetermined time period T1, and the minimum value and the maximum value of the input voltage are acquired and held.

FIG. 3B shows the maximum value acquired and held by monitoring the input voltage, and FIG. 3C shows the minimum value acquired and held by the input voltage monitoring. In the example of FIG. 3, the maximum value is the maximum peak voltage on the positive side of the input voltage, and the minimum value is the maximum peak voltage on the negative side of the input voltage.

Next, in the cycle detection trial period T2, an optimal provisional cycle detection mode for detecting the cycle of the input voltage is determined based on the minimum value and the maximum value of the input voltage (step S23 in FIG. 2). Thereafter, the predetermined period, period and phase are detected in the provisional period detection mode (step S24 in FIG. 2). In this period T2, the period and phase may be detected simultaneously in a plurality of period detection modes.

Next, the error of the period detected in the provisional period detection mode is calculated (step S25 in FIG. 2), and it is determined whether or not the error is within a predetermined reference range (step S26). The determination of the cycle error may be performed by determining whether the difference between the minimum value and the maximum value of the detected cycle is less than a predetermined value or less than a predetermined ratio, or the detected cycle is within a fluctuation range corresponding to an allowable error of the commercial power supply frequency. Or the like.

When the error of the period detected in the provisional period detection mode is within a predetermined reference range (Yes in step S26), the provisional period detection mode is detected and the period and phase of the input voltage in AC / DC conversion are detected. The period detection mode to be determined is determined (step S27). When period detection by a plurality of period detection modes is performed at the same time, the period detection mode is determined from those in which the error of the period satisfies the predetermined criterion.

When there are a plurality of period detection modes that satisfy a predetermined standard, a priority order may be set in advance in the period detection mode, and the period detection mode may be determined based on the priority order. Or you may make it determine the period detection mode with the smallest period error. Alternatively, the most advantageous cycle detection mode may be determined for a parameter of voltage fluctuation such as a momentary power failure in which the cycle is easily erroneously detected.

If any error in the period detected in the provisional period detection mode is not within the predetermined reference range (No in step S26), the period detection operation is stopped, and the period detection operation is periodically performed by the timer. Performs repeated control.

In the period detection period T3 during normal operation after the period detection trial period T2, period detection is performed using the period detection mode determined in the period detection trial period T2. In the period detection period T3 during normal operation, after the period detection mode is determined, the minimum and maximum values of the input voltage are continuously monitored, and the period detection in the alternative candidate period detection mode is performed on a trial basis. It may be.

At this time, the period detection mode to be performed on a trial basis is switched according to the minimum value and the maximum value of the input voltage. When the period of the input voltage is being detected in the determined period detection mode, if the period fluctuates by a predetermined ratio or a predetermined value or more, the detection period by the alternative candidate period detection mode that is being executed on a trial basis is normal. If it is a value (a period close to the previous detection period), it may be configured to switch to the alternative candidate period detection mode.

Note that the operation of determining the cycle detection mode in the cycle detection trial period T2 described above is omitted, cycle detection is performed in the provisional cycle detection mode from the startup, and the cycle variation or voltage variation of the input voltage is large. When the condition is not satisfied, the provisional cycle detection mode may be switched to the alternative candidate cycle detection mode.

FIG. 4 shows a first embodiment of determining the period detection mode based on the maximum value and the minimum value of the input voltage. In the first embodiment, an AC voltage having a maximum value as a positive voltage and a minimum value as a negative voltage is input as an input voltage. In FIG. 4, the horizontal axis indicates the maximum value (positive voltage) of the input voltage, and the voltage increases toward the right side. The vertical axis indicates the minimum value (negative voltage) of the input voltage, and the voltage decreases as it goes upward (the absolute value increases).

As shown in FIG. 4, the maximum value of the input voltage exceeds, for example, the positive-side startable voltage (+ first threshold voltage), and the minimum value of the input voltage, for example, the negative-side startable voltage (−first threshold value). If the voltage is lower than the voltage, the first cycle detection mode M1 is selected.

In this case, the input voltage is a normal normal AC voltage that appears as a voltage higher than the startable voltage (first threshold voltage) on the positive side and the negative side. As the first period detection mode M1, the input voltage For example, it is possible to set a mode in which the timing of crossing 0 volts is detected and the period of the input voltage is detected.

Also, the maximum value of the input voltage exceeds the positive startable voltage (+ first threshold voltage), the minimum value of the input voltage exceeds the negative startable voltage (−first threshold voltage), and sensor error When the voltage (−second threshold voltage) is below, the second cycle detection mode M2 is selected.

In this case, the positive-side peak voltage is sufficiently large, but the negative-side peak voltage is small. For example, as the second period detection mode M2, for example, the threshold voltage on the side where the peak voltage of the input voltage is larger (for example, A mode in which the input voltage period is detected by detecting the timing at which the input voltage crosses (sensor error voltage) can be set.

Also, when the maximum value of the input voltage exceeds the positive startable voltage (+ first threshold voltage) and the minimum value of the input voltage exceeds the negative sensor error voltage (−second threshold voltage) The third cycle detection mode M3 is selected.

In this case, the positive-side peak voltage is sufficiently large, but the negative-side peak voltage is even smaller. When it is difficult to accurately predict the input voltage, the third period detection mode M3 is used. Without using a fixed threshold voltage, for example, a voltage that is a quarter of the difference between the positive peak voltage and the negative peak voltage of the input voltage is calculated, and the positive peak voltage or the negative peak voltage is calculated. A mode in which the input voltage period is detected by detecting the timing at which the input voltage straddles a voltage that is one fourth of the voltage away from the peak voltage can be set.

In addition, the maximum value of the input voltage is below the positive startable voltage (+ first threshold voltage) and above the sensor error voltage (+ second threshold voltage), and the minimum value of the input voltage is startable on the negative side When the voltage is lower than the first threshold voltage, the second cycle detection mode M2 is selected.

In this case, the negative-side peak voltage is sufficiently large, but the positive-side peak voltage is small. As the second cycle detection mode M2, the threshold voltage (for example, sensor error) on the side where the input voltage peak voltage is larger is used. In this mode, the input voltage cycle can be detected by detecting the timing at which the input voltage crosses the voltage.

When the maximum value of the input voltage is below the positive sensor error voltage (+ second threshold voltage) and the minimum value of the input voltage is below the negative startable voltage (-first threshold voltage) The third cycle detection mode M3 is selected.

In this case, the negative-side peak voltage is sufficiently large, but the positive-side peak voltage is even smaller. If it is difficult to accurately predict the input voltage, the third period detection mode M3 is used. For example, the voltage of a quarter of the difference between the positive peak voltage and the negative peak voltage of the input voltage is calculated, and the quarter voltage is calculated from the positive peak voltage or the negative peak voltage. It is possible to set a mode for detecting the cycle of the input voltage by detecting the timing at which the input voltage is straddled by a voltage that is far away.

If the maximum value of the input voltage is lower than the startable voltage (+ first threshold voltage) and the minimum value of the input voltage is higher than the startable voltage (−first threshold voltage), AC / DC Since the power converter 16 cannot be started, the period / phase detection processing unit 14 performs control to stop the period detection operation and periodically re-execute the period detection operation by the timer.

FIG. 5 shows a second embodiment of selection of the period detection mode based on the minimum value and the maximum value of the input voltage. The second embodiment is an embodiment in which a voltage having a maximum value as a positive voltage and a negative voltage and a minimum value as a positive voltage and a negative voltage is input as the input voltage.

In FIG. 5, the horizontal axis indicates the maximum value of the input voltage, and the voltage increases as it goes to the right, with the positive voltage on the right and the negative voltage on the left with 0V as the center. The vertical axis indicates the minimum value of the input voltage, and the voltage increases as it goes upward, with a positive voltage at the top and a negative voltage at the bottom, centered on 0V. Note that the shaded area in FIG. 5 is an area in which the maximum value of the input voltage is smaller than the minimum value, and is an area that is not possible.

As shown in FIG. 5, the maximum value of the input voltage exceeds, for example, the positive-side startable voltage (+ first threshold voltage), and the minimum value of the input voltage, for example, is the negative-side startable voltage (−first threshold value). If the voltage is lower than the voltage, the first cycle detection mode M1 is selected. The first cycle detection mode M1 can be the same mode as the first cycle detection mode M1 described with reference to FIG.

Also, the maximum value of the input voltage exceeds the positive startable voltage (+ first threshold voltage), the minimum value of the input voltage exceeds the negative startable voltage (−first threshold voltage), and sensor error When the voltage (−second threshold voltage) is below, the second cycle detection mode M2 is selected. The second cycle detection mode M2 can be the same mode as the second cycle detection mode M2 described with reference to FIG.

Also, the maximum value of the input voltage exceeds the positive startable voltage (+ first threshold voltage), and the minimum value of the input voltage exceeds the negative sensor error voltage (−second threshold voltage). When the sensor error voltage is lower than (+ second threshold voltage), the third cycle detection mode M3 is selected. The third cycle detection mode M3 can be the same mode as the third cycle detection mode M3 described with reference to FIG.

Also, when the maximum value of the input voltage exceeds the positive startable voltage (+ first threshold voltage) and the minimum value of the input voltage exceeds the positive sensor error voltage (+ second threshold voltage) The fourth cycle detection mode M4 is selected. In this case, since the maximum value of the input voltage is a positive voltage and the minimum value is also a positive voltage, the input voltage may be an input voltage from a DC power source, and it is impossible to detect the cycle from the DC input voltage. In the fourth period detection mode M4, the period / phase signal is generated using the clock source provided in the period / phase detection processing unit 14, and the period / phase signal is converted into an AC / DC power conversion control unit. 15 may be configured to notify.

In addition, the minimum value of the input voltage is below the negative startable voltage (-first threshold voltage), the maximum value of the input voltage is below the positive startable voltage (+ first threshold voltage), and sensor error When the voltage (+ second threshold voltage) is exceeded, the second cycle detection mode M2 is selected. The second cycle detection mode M2 can be the same mode as the second cycle detection mode M2 described with reference to FIG.

Also, the minimum value of the input voltage is below the negative startable voltage (-first threshold voltage), and the maximum value of the input voltage is below the positive sensor error voltage (+ second threshold voltage). When the sensor error voltage (−second threshold voltage) is exceeded, the third cycle detection mode M3 is selected. The third cycle detection mode M3 can be the same mode as the third cycle detection mode M3 described with reference to FIG.

Also, when the minimum value of the input voltage is below the negative startable voltage (-first threshold voltage) and the maximum value of the input voltage is below the negative sensor error voltage (-second threshold voltage) The fourth cycle detection mode M4 is selected. In this case, since the maximum value of the input voltage is a negative voltage and the minimum value is also a negative voltage, the input voltage may be an input voltage from a DC power source, and it is not possible to detect the cycle from the DC input voltage. In the fourth period detection mode M4, the period / phase signal is generated using the clock source provided in the period / phase detection processing unit 14, and the period / phase signal is converted into an AC / DC power conversion control unit. 15 may be configured to notify.

If the maximum value of the input voltage is lower than the startable voltage (+ first threshold voltage) and the minimum value of the input voltage is higher than the startable voltage (−first threshold voltage), AC / DC Since the power converter 16 cannot be started, the period / phase detection processing unit 14 performs control to stop the period detection operation and periodically re-execute the period detection operation by the timer.

FIG. 6 shows an example of the first period detection mode M1. FIG. 6A shows the waveform of the input voltage detected by the AC voltage sensor 12. (B) shows the count value of the period counter. The period / phase detection processing unit 14 starts counting up a half-cycle counter that counts up at a period of 36 KHz, for example, at the timing when the zero-cross edge point R of the input voltage is detected.

Once the period / phase detection processing unit 14 detects the zero-cross edge point R of the input voltage, until the half-period counter exceeds a count value M corresponding to a predetermined time threshold value Tm that is a mask period, Do not detect the next zero-cross point.

The cycle / phase detection processing unit 14 sets a value of, for example, about 40% (≈25 / 64) of one cycle as the count value M corresponding to the predetermined time threshold value Tm. The predetermined time threshold value Tm can be determined based on a period obtained by adding a margin to the allowable phase fluctuation width due to the nominal frequency fluctuation of the AC voltage.

By detecting the zero-cross edge point R of the input voltage, the phases of the input voltage 0 degree and 180 degrees are detected, and the half period is detected by the count value obtained by counting up between the zero-cross edge points R with a predetermined period. Is done. By inputting the input voltage detected by the AC voltage sensor 12 to the zero-cross detection processing unit 14 as a digital signal from an AD converter or the like, the zero-cross detection processing unit 14 uses a processor such as a CPU to perform the AC voltage conversion by software processing. Zero cross can be detected.

FIG. 7 shows an example of the second cycle detection mode M2. FIG. 7A shows a waveform example of the input voltage. (B) shows the count value of the positive voltage threshold value lowering continuation counter. (C) shows the count value of the negative voltage threshold value exceeding continuation counter. (D) shows the count value of the cycle detection counter that detects one cycle on the positive side, and (e) shows the count value of the cycle detection counter that detects one cycle on the negative side.

As shown in FIG. 7, a point P exceeding the positive voltage threshold value Vpth or a point Q falling below the negative voltage threshold value Vmth is detected, and the point P or the point Q is used as a detection phase of one cycle. The point P and the next point P are used for the detection phase of one cycle (one cycle on the positive side) immediately before the transition to the negative voltage after the transition to the positive voltage and then the transition to the positive voltage again. Further, the point Q and the next point Q are used for the detection phase of one cycle (one cycle on the negative side) immediately after the transition to the negative voltage, the transition to the positive voltage, and the next transition to the negative voltage again.

The count value of the continuation counter below the positive voltage threshold and the count value of the continuation counter above the negative voltage threshold are used for mask period setting to prevent erroneous detection of the cycle due to noise near 0 volts of the input voltage. It can be used for detecting an instantaneous power failure.

FIG. 8 shows an example of the third period detection mode M3. FIG. 8A shows a waveform example of the input voltage. (B) shows the count value of the period detection counter. As shown in FIG. 8, a voltage (D / 4) that is a quarter of the difference D between the positive peak voltage and the negative peak voltage of the input voltage (D / 4) is calculated, and the positive peak voltage or the negative peak voltage is calculated. The period of the input voltage can be detected by detecting the timing at which the input voltage crosses the points J and K of the voltage separated from the peak voltage by a quarter voltage.

In the example of FIG. 8, an example is shown in which a half-cycle is detected from a timing above point J to a timing below point K and from a timing below point K to a timing above point J. Note that it may be configured to detect one cycle from a timing exceeding the point J to a timing exceeding the next point J, or from a timing falling below the point K to a timing falling below the next point K.

In the cycle detection mode control device according to the present embodiment, based on the maximum value and the minimum value of the input voltage, by selecting the cycle detection mode using the optimum threshold for cycle detection and detecting the cycle and phase, More accurate period and phase detection can be performed for various input voltage waveforms.

Also, it becomes possible to further increase the voltage width and the type of waveform of the input voltage that can be used as an input voltage that can operate an apparatus such as an AC-DC converter. In addition, detection of a period necessary for PFC control can be performed in an optimum detection mode for input voltages other than a sine waveform.

Also, it is possible to determine whether or not the apparatus can operate at the input voltage by obtaining the maximum value and the minimum value of the input voltage and comparing them with the startable voltage. In addition, when the waveform of the input voltage from the power source is unstable, it is possible to recover from an abnormal input voltage by repeatedly performing input voltage determination and period detection.

As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment described above, A various structure or embodiment can be taken in the range which does not deviate from the summary of this invention. it can.

DESCRIPTION OF SYMBOLS 11 Periodic transition voltage source 12 AC voltage sensor 13 Maximum value / minimum value detection unit 14 Period / phase detection processing unit 15 AC / DC power conversion control unit 16 AC / DC power converter

Claims (4)

1. Maximum value / minimum value detecting means for monitoring the input voltage for a predetermined time and obtaining the minimum value and the maximum value of the input voltage;
   Detected by the maximum / minimum value detection means from a plurality of period detection modes for detecting the timing at which the input voltage crosses any one of a plurality of different threshold voltages and detecting the period and phase of the input voltage. Period / phase detection processing means for selecting at least one period detection mode based on the minimum value and the maximum value of the input voltage, and detecting the period and phase of the input voltage in the selected period detection mode;
   A cycle detection mode control device.
2. The period / phase detection processing means selects one or a plurality of provisional period detection modes, detects the period and phase of the input voltage in the provisional period detection mode, and an error of the detected period is predetermined. Is determined to be within a predetermined reference range, and when it is within the predetermined reference range, one of the provisional cycle detection modes is determined as a cycle detection mode for detecting the cycle and phase of the input voltage. The period detection mode control device according to claim 1.
3. A maximum value / minimum value detection step of monitoring the input voltage for a predetermined time and obtaining a minimum value and a maximum value of the input voltage;
   Detected in the maximum value / minimum value detection step from a plurality of period detection modes for detecting the timing at which the input voltage crosses any one of a plurality of different threshold voltages and detecting the period and phase of the input voltage. A period / phase detection processing step of selecting at least one of the period detection modes based on the minimum value and the maximum value of the input voltage, and detecting the period and phase of the input voltage in the selected period detection mode;
   A cycle detection mode control method including:
4. In the period / phase detection processing step, one or a plurality of provisional period detection modes are selected, the period and phase of the input voltage are detected by the provisional period detection mode, and an error of the detected period is predetermined. Is determined to be within a predetermined reference range, and when it is within the predetermined reference range, one of the provisional cycle detection modes is determined as a cycle detection mode for detecting the cycle and phase of the input voltage. The period detection mode control method according to claim 3.

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