JP2010283980A - Power supply unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply unit for maintaining input power factor by attaining high accuracy of zero-cross detection of an AC power supply. <P>SOLUTION: The power supply unit maintaining a high power factor is constituted of an input section 8 waiting for an edge of only one direction of either a leading edge or a trailing edge of a binary signal in short-circuiting an AC power supply via a reactor 2, on the basis of the binary signal corresponding to a magnitude relation between an AC voltage of the AC power supply 1 and a predetermined reference signal; a determining section 9 for determining whether the time detected from a pulse width of the binary signal and the edge direction should be stored and whether the edge direction a waited for by the input section 8 should be switched; a storage section 10 for storing the time and the edge direction of the loading edge or the trailing edge of the binary signal, on the basis of the determining section 9; and a calculating section 11 for calculating a subsequent zero-cross point by using an intermediate point between the times corresponding to the leading edge and the trailing edge stored most recently in the storage section 10 and the cycle of the AC power supply. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply apparatus that rectifies an AC voltage from an AC power supply and supplies a DC voltage to a load.

  A method has been devised that corrects the output timing of a PAM waveform and reliably generates a predetermined PAM waveform when the zero cross point is shifted due to power supply voltage distortion or binary signal chattering (for example, see Patent Document 1). As shown in FIG. 7, when the falling position of the binary signal is shifted to the left side, the shift of the falling position is absorbed by correcting the start position of the count by Δt. A pulse signal having a PAM waveform can be output at the same timing.

  On the other hand, a method of calculating the zero crossing time of the power supply voltage using the rising time and falling time of the binary signal has also been proposed (for example, see Patent Document 2). As is apparent from FIG. 8, the intermediate time tp between the rise time ton (2) and the fall time toff (2) of the power supply voltage waveform is the peak time of the power supply voltage. Therefore, a time that is 90 degrees (tac / 4) behind the peak time tp is the falling zero-cross time, and a time that is 270 degrees (3 · tac / 4) behind the peak time tp is the rising zero-cross time.

JP 2008-253102 A JP 2001-45763 A

  However, although the above-described conventional power supply apparatus has relatively good characteristics, a method for correcting the signal according to the amount of deviation of the falling signal of the binary signal as shown in FIG. 7 is a distortion of the power supply voltage or chattering of the binary signal. However, when the power supply voltage is distorted at each cycle as shown in FIG. 2, the binary signal always shifts, so that it is difficult to accurately detect the zero cross point. On the other hand, the method of calculating the zero-cross time from the rise time and the fall time of the binary signal as shown in FIG. 2 was able to obtain the zero-cross time accurately, but the distortion of the power supply voltage and the chattering of the binary signal However, the problem was insufficient.

  The power supply apparatus of the present invention solves the conventional problems as described above, and accurately detects the zero cross point of the AC power supply even when the binary signal as shown in FIG. 2 is generated due to distortion or chattering of the power supply voltage. It is an object of the present invention to provide a power supply device that can be used.

In order to solve the above problems, the power supply apparatus of the present invention outputs a binary signal corresponding to the magnitude relationship between the AC voltage of the AC power supply and a predetermined reference voltage, and a short-circuit means for short-circuiting the AC power supply through the reactor. And a power supply apparatus having a control means for driving the short-circuit means based on the binary signal, an input unit that waits for only one of the rising edge and the falling edge of the binary signal, and the binary signal A determination unit that determines whether or not to store the time and edge direction detected according to the pulse width and whether or not to switch the direction of the edge that the input unit waits; and the rising edge of the binary signal based on the determination unit Or the storage unit that stores the time and the edge direction of the falling edge, and the midpoint of each time corresponding to the rising edge and the falling edge stored in the storage unit and the AC power supply Using cycle is obtained with a calculation unit for calculating a next zero-crossing point.

  As a result, every time a rising edge or falling edge of a binary signal is detected, an edge in the opposite direction to the detected edge and the time and edge detected from the most recently stored time are detected. By determining whether or not to store the direction, it is possible to accurately detect the zero cross point of the AC power supply even if the binary signal as shown in FIG. 2 is obtained, so that a high power factor can be maintained.

  The power supply apparatus of the present invention can accurately detect the zero cross point of the AC power supply even if the detection position of the binary signal is shifted due to distortion of the power supply voltage or chattering of the binary signal, so that a high power factor can be maintained. Can do.

Configuration diagram of power supply device according to Embodiment 1 of the present invention Waveform diagram showing the relationship between AC input voltage and binary signal when chattering occurs Explanatory drawing of each part operation | movement in Embodiment 1 of this invention The flowchart which shows the processing content of the judgment part in Embodiment 1 of this invention. Explanatory drawing of the calculation part in Embodiment 1 of this invention Explanatory drawing of each part operation | movement in Embodiment 2 of this invention Configuration diagram according to an example of a conventional power supply circuit Configuration diagram according to an example of a conventional converter circuit

  The first invention is based on a short circuit means for short-circuiting an AC power supply through a reactor, a means for outputting a binary signal corresponding to the magnitude relationship between the AC voltage of the AC power supply and a predetermined reference voltage, and the binary signal. In the power supply apparatus having the control means for driving the short-circuit means, the input section waiting for only one of the rising edge and the falling edge of the binary signal and the pulse width of the binary signal is detected. A determination unit that determines whether to store the time and edge direction and whether to switch the direction of the edge that the input unit waits; and the time and edge of the rising edge or falling edge of the binary signal based on the determination unit The storage unit that stores the direction, and the next zero cross point using the midpoint of each time corresponding to the rising and falling edges most recently stored in the storage unit and the cycle of the AC power supply By providing a calculation unit to calculate, every time a rising edge or falling edge of a binary signal is detected, the detected edge is the edge opposite to the detected edge and the time from the most recently stored time. By determining whether or not to memorize the time and the direction of the edge, it is possible to accurately detect the zero-cross point of the AC power supply even if the binary signal as shown in FIG. Can be maintained.

  In the second invention, in particular, each time the rising edge or the falling edge of the binary signal is detected, the determination unit of the first invention is stored in the edge opposite to the detected edge and most recently. When the time from the time is smaller than the first predetermined value, the input unit is switched to a state waiting for an edge in the direction opposite to the detected edge, which is larger than the first predetermined value and binary. When the signal is smaller than a second predetermined value set in advance for each rising edge or falling edge of the signal, the input unit is kept waiting for an edge in the same direction as the detected edge. When larger than a predetermined value, after the detected time and edge direction are stored in the storage unit, the input unit is switched to a state waiting for an edge opposite to the detected edge. Yes, it is possible to accurately determine the zero crossing point of the AC power supply by determining whether or not to store the detected time and edge direction by providing two threshold values of the first predetermined value and the second predetermined value. It can be realized.

  The third aspect of the invention is a power supply apparatus that is obtained by calculating the detection cycle of the rising edge or the falling edge, in particular using the period of the AC power supply according to the first to second aspects of the invention for the calculation unit. By setting the edge detection cycle used for the calculation of the calculation unit as the cycle of the AC power supply, the zero cross point of the AC power supply can be detected with higher accuracy.

  The fourth aspect of the invention relates to a rising edge or a falling edge that uses the AC power supply cycle of the first to third aspects of the invention for calculation, and a rising edge or a falling edge that is used to calculate the zero-cross point one cycle before. A power supply device that is obtained by setting a time difference between edges, and the AC power supply cycle is the time difference between the most recently stored rising edge or falling edge and the rising edge or falling edge stored one cycle ago. By doing so, the zero cross point can be accurately detected even if the cycle of the AC power supply fluctuates.

  According to a fifth aspect of the present invention, in particular, when the detection cycle of the rising edge or the falling edge used for the calculation of the calculation units of the first to fourth aspects is equal to or greater than a preset upper limit value or less than a lower limit value, the determination unit Is a power supply device that is determined to be abnormal and the short-circuiting means is stopped. If the determination unit determines that the abnormality is abnormal according to the detection period, the short-circuiting means is assumed if the AC power supply cycle becomes an unexpected value. System safety can be improved.

  In the sixth aspect of the invention, in particular, the calculation unit of the first to fifth aspects of the invention adds the following time from the zero cross point calculated one cycle before the time corresponding to approximately 3/4 of the cycle of the AC power supply. It is a power supply device that calculates the zero-cross point. By calculating the next zero-cross point near the peak time of the AC power supply, it is calculated using an incorrect time that is too close to the edge of the regular binary signal. Therefore, it is possible to cope with frequency fluctuations most.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram showing a power supply device according to a first embodiment of the present invention. In FIG. 1, an AC power source 1 is input to a bridge circuit including four diodes 4 a, 4 b, 4 c, and 4 d via a reactor 2. A smoothing capacitor 5 and a load 6 are connected to the output of the bridge rectifier circuit. Further, the power factor of the power supply device is improved by connecting the short-circuit means 3 for short-circuiting the AC power supply 1 from the output end of the AC power supply 1 via the reactor 2.

  Further, a binary signal output means 7 is connected to both ends of the AC power supply 1 for outputting the phase of the power supply voltage of the AC power supply 1 as a binary signal and supplying the binary signal to the input unit 8.

  As shown in FIG. 2, this binary signal output means 7 is configured to output an ON-OFF signal according to the power supply voltage. For example, when the power supply voltage exceeds a certain reference value, the ON signal is output. However, it becomes OFF when the value is below the reference value. For example, there is a configuration assembled with a photocoupler or the like, and the predetermined reference voltage in the first embodiment includes a value very close to 0V or 0V. Further, FIG. 2 shows a waveform in which a binary signal is output in the positive cycle of the AC power supply 1, but the first embodiment can also be used in a waveform in which a binary signal is output in the negative cycle.

Next, as shown in FIG. 2, when the chattering of the binary signal occurs, the binary signal is repeatedly turned on and off at a cycle shorter than normal. If the binary signal is used for calculation of the zero cross point as it is, a point different from the original zero cross point of the AC power source 1 is calculated. Therefore, every time a rising edge or falling edge of a binary signal is detected, the edge of the detected edge is determined by the time from the most recently stored time at the edge opposite to the detected edge. It is determined whether or not to store, and only the most recently stored time is used for the calculation of the zero cross point.

  Assuming that there is a problem in the input of the AC power supply 1 and the binary signal periodically shifts, a thin pulse tz1 (for example, about 1 μs) at a certain distance tz2 from the regular pulse tz3 as shown in FIG. ) Occurs in general, and the present invention is effective in accurately detecting the zero cross point of the AC power supply 1 in the case of a binary signal as shown in FIG.

  Next, operation | movement of the judgment part 9 is demonstrated using the flowchart shown in FIG. First, every time a rising edge or falling edge of a binary signal is detected, the time from the most recently stored time at the edge opposite to the detected edge is the second in step (a). If it is larger than the predetermined value, it is determined that the normal pulse width has been achieved, and the time and edge direction detected by proceeding to step (e) and step (e) are stored in the storage unit 10, and the input unit 8 is switched to a state of waiting for an edge opposite to the detected edge. On the other hand, if it is smaller than the second predetermined value in step (a), the process proceeds to step (yes). If it is smaller than the first predetermined value, the input unit 8 is detected in the direction opposite to the edge detected in step (e). Switch to the state of waiting for the edge. Note that if it is greater than the first predetermined value in step (i), nothing is processed and the process proceeds to the end flag.

  Next, in the case of the binary signal shown in FIG. 3, which time the input unit 8 waits for and which edge the time is stored in the storage unit 10 will be described in order. It is assumed that the second predetermined value is set to be larger than tz2 so that the first predetermined value in FIG. 3 is larger than tz1 and smaller than tz2.

  First, the rising edge time T1 is stored in the storage unit 10 at time (1), and the input unit 8 is switched from waiting for a rising edge to waiting for a falling edge.

  Next, since the time until the latest rising edge time T1 at time (2) is smaller than the first predetermined value, the falling edge time at time (2) is not stored in the storage unit 10, The input unit 8 is switched from waiting for the falling edge to waiting for the rising edge.

  Next, the most recent falling edge at time (3) is the last falling edge from time (1) because the time at time (2) is not stored, and at time (3). The time until the latest falling edge time is greater than tz3. That is, since it becomes larger than the second predetermined value, the time T3 of the rising edge at time (3) is stored in the storage unit 10, and the input unit 8 is switched from waiting for the rising edge to waiting for the falling edge.

  Next, the time until the latest rising edge time T3 at time (4) becomes larger than the second predetermined value, and the rising edge time T4 at time (4) is stored in the storage unit 10 and is input to the input unit. 8 is switched from waiting for the falling edge to waiting for the rising edge.

  Next, the time until the latest falling edge time T4 at time (5) is smaller than the second predetermined value, but is larger than the first predetermined value, and the rising edge at time (5). The time is not stored in the storage unit 10, and the input unit 8 is kept waiting for the current rising edge. Subsequently, even if a falling edge is output at time (6), the rising edge is waited at time (5), so no processing is performed at time (6) and the rising edge is continuously waited.

By processing as described above, the time stored in the storage unit 10 from the point A to the point C becomes the rising edge time T1, the rising edge time T3, and the falling edge time T4.

  Next, the operation of the calculation unit 11 will be described. The calculation unit 11 calculates the zero cross point C from the time stored in the storage unit 10 between the points B and C in FIG. 3, and the next rising edge time T3 and the falling edge of the next zero cross point C The intermediate time tp of time T4 is the peak time of the power supply voltage. Therefore, a time that is delayed by 270 degrees (3 · tac / 4) from the peak time tp becomes the rising zero-cross point C. Here, tac is the period of the AC power supply 1, and is a predetermined value such as 20 ms for a 50 Hz power supply and 16.667 ms for a 60 Hz power supply. In FIG. 3, the rising zero-cross point is calculated, but the falling zero-cross point that is 450 degrees (5 · tac / 4) later than the peak time tp, and the zero-cross points after the second period are also included. It can also be calculated similarly.

  This time, both the rising edge time T1 and the rising edge time T3 are stored, but the calculation unit 11 uses the latest rising edge time T3 of the next zero cross point C to calculate the zero cross point C. At the time of 3), the information of the falling edge time T3 may be overwritten on the rising edge time T1.

  Further, the time when the calculation unit 11 calculates the next zero-cross point C may be performed before the next zero-cross point C, but if it is too close to the edge of the regular binary signal, the calculation is performed using an incorrect time. there is a possibility. For example, as shown in FIG. 5, the calculation is performed using an incorrect time by calculating a time (point P) obtained by adding about 3/4 tac from the zero cross point A one cycle before, that is, near the peak time of the AC power supply 1. Therefore, it is possible to cope with frequency fluctuations most.

(Embodiment 2)
FIG. 6 is a waveform diagram showing the power supply device according to the second embodiment of the present invention. The zero cross point C is calculated with the period of the AC power supply 1 as the detection period tac (n) of the falling edges tb and tc. For example, if a predetermined value such as 20 ms for a 50 Hz power supply or 16.667 ms for a 60 Hz power supply is set in advance, the zero crossing point calculated from the peak time tp will fluctuate if the period of the AC power supply 1 fluctuates. End up. However, by using the detection cycle tac (n) of the falling edges tb and tc, if the cycle changes, the falling edge time naturally changes, so that it is possible to cope with the cycle change.

  Furthermore, a period obtained by averaging the detection periods tac (n) of the falling edges tb and tc, the detection period tac (n−1), and the previous detection period is used for calculating the zero cross point C. By doing so, it is possible to cope with variations in the period, and therefore the zero cross point of the AC power supply 1 can be calculated with higher accuracy.

  Further, when the detection cycle tac (n) of the falling edges tb and tc is equal to or greater than the preset upper limit value or less than the lower limit value, the determination unit 9 causes the input unit 8 to wait for which edge direction and the storage unit Rather than determining whether or not to store the time in 10, the abnormal signal is preferentially output to the control unit 12 via the storage unit 10 and the calculation unit 11 or directly to the control unit 12, and the short-circuit unit 3 is stopped. To do. If the cycle of the AC power supply becomes an unexpected value, the operation is not continued and the operation is continued, but the determination unit 9 determines that there is an abnormality and stops the short-circuit means 3 to improve the safety of the system. To do.

  In FIG. 6, the detection cycle between falling edges has been described. However, the detection cycle between rising edges can also be used in the second embodiment.

  As described above, the power supply apparatus according to the present invention can accurately detect the zero-cross point of the AC power supply even if the detection position of the binary signal is shifted due to distortion of the power supply voltage or chattering of the binary signal. The present invention can be applied as a power supply device for appliances such as a harmony machine and refrigerator, and a washing machine, and a detection device for detecting the phase of the input voltage of an AC power supply.

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Reactor 3 Short circuit means 4a, 4b, 4c, 4d Diode 5a, 5b Electrolytic capacitor 6 Load 7 Binary signal output means 8 Input part 9 Judgment part 10 Storage part 11 Calculation part 12 Control part

Claims (6)

Short-circuit means for short-circuiting the AC power supply through the reactor, means for outputting a binary signal corresponding to the magnitude relationship between the AC voltage of the AC power supply and a predetermined reference voltage, and the short-circuit means based on the binary signal In the power supply apparatus having a control means for driving the input signal, an input unit that waits for only one of the rising edge and the falling edge of the binary signal and the time detected according to the pulse width of the binary signal A determination unit that determines whether or not to store the edge direction and whether to switch the direction of the edge that the input unit waits, and the time of the rising edge or falling edge of the binary signal based on the determination unit And a storage unit for storing the edge direction, the midpoint of each time corresponding to the rising edge and the falling edge most recently stored in the storage unit, and the frequency of the AC power supply Power supply, characterized in that it comprises a calculation unit for calculating a next zero-crossing point with. Whenever the rising edge or falling edge of the binary signal is detected, the determination unit is the edge opposite to the detected edge and the time from the most recently stored time is the first time When the value is smaller than a predetermined value, the input unit is switched to a state of waiting for an edge in a direction opposite to the detected edge, which is larger than the first predetermined value and the rising edge or the rising edge of the binary signal. When the value is smaller than a second predetermined value set in advance for each falling edge, the input unit is kept waiting for an edge in the same direction as the detected edge. If larger, the detected time and edge direction are stored in the storage unit, and then the input unit is switched to a state waiting for an edge opposite to the detected edge. The power supply device according to claim 1. 3. The power supply device according to claim 1, wherein the cycle of the AC power supply is obtained by calculating a detection cycle of a rising edge or a falling edge used for calculation by a calculation unit. The cycle of the AC power supply is a time difference between a rising edge or a falling edge used for calculation of a calculation unit and a rising edge or a falling edge used for calculation of a zero cross point one cycle before. The power supply device according to any one of 1 to 3. When the detection period of the rising edge or the falling edge used for the calculation of the calculation unit is equal to or higher than a preset upper limit value or less than the lower limit value, the determination unit determines that the abnormality is present and stops the short-circuiting unit. The power supply device according to any one of claims 1 to 4. The calculation unit calculates a next zero cross point at a time obtained by adding a time corresponding to approximately 3/4 of the cycle of the AC power supply from the zero cross point calculated one cycle before. The power supply device according to any one of?