JP2017118646A - Hot water supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water supply device which can continue operation if an instantaneous blackout or an instantaneous voltage drop occurs.SOLUTION: A hot water supply device includes a control device 51, load equipment controlled by the control device 51, and a power supply 6. The power supply 6 includes: a smoothing capacitor C1 which smooths a voltage whose supply source is an external power supply, to generate a DC voltage V1; two switching devices, each connected to the smoothing capacitor C1; a load power supply unit 63 which controls to alternately make the conduction of the two switching devices, so as to intermittently take in the DC voltage V1 to generate a step-down voltage from the DC voltage V1, to supply to the load equipment; and a control power supply unit 64 which generates a step-down voltage from the DC voltage V1 to supply to the control device 51. The load power supply unit 63 is configured not to make the conduction of one of the two switching devices, if the deterioration of the supply voltage of the external power supply is detected when performing the control to alternately make the conduction of the two switching devices.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a hot water supply device including a power supply device.

  2. Description of the Related Art Conventionally, in a hot water supply apparatus, a power supply device provided therein rectifies and smoothes an AC voltage supplied from an AC power source such as a commercial power source by a diode bridge and a smoothing capacitor, and is further connected to a smoothing capacitor. The voltage smoothed by the smoothing capacitor is stepped down and supplied as the power supply voltage of the control device that controls the load device in the hot water supply device. Further, a load power supply unit is connected to the smoothing capacitor, and the voltage smoothed by the smoothing capacitor in the load power supply unit is stepped down and supplied as a drive voltage for the load device in the hot water supply apparatus. That is, the terminal voltage of the smoothing capacitor is supplied to both the control power supply unit and the load power supply unit, and each functions as a DC-DC converter.

  On the other hand, Patent Documents 1 and 2 describe a power supply apparatus for which an AC input voltage is shared between a 100V system and a 200V system. The power supply apparatus includes a converter transformer and two switching elements that intermittently output a DC input voltage obtained by rectifying and smoothing an AC input voltage and output the intermittent input voltage to the primary winding of the converter transformer. The push-pull operation for operating two switching elements and the single-end operation for operating only one switching element can be switched according to the magnitude of the AC input voltage.

JP 2000-184708 A JP 2001-136744 A

  By the way, in the above-described hot water supply apparatus, when an instantaneous power failure or instantaneous voltage drop occurs in the main power source such as a commercial power source, the energy stored in the smoothing capacitor is consumed in both the control power source unit and the load power source unit, The voltage of the smoothing capacitor decreases. In particular, when a push-pull type DC-DC converter using two switching elements is employed in the power supply unit for load, compared to a case where a single type using one switching element is employed. Therefore, the consumption speed of the stored energy of the smoothing capacitor is large, and the voltage drop speed of the smoothing capacitor is fast. Further, in the case of the push-pull method, the operation is performed until the voltage of the smoothing capacitor becomes a considerably low voltage, so that the rate of decrease in the voltage of the smoothing capacitor is further increased.

  Thus, when an instantaneous power failure or instantaneous voltage drop occurs and the voltage of the smoothing capacitor decreases, the voltage generated in the load power supply unit and the control power supply unit also decreases. And if the fall of the voltage supplied to a control apparatus from a control power supply part becomes remarkable, a driving | operation of a hot water supply apparatus will be stopped by a control apparatus stopping. Once the hot water supply device stops its operation during the hot water supply operation, there is a problem that the operation cannot be resumed immediately even if the instantaneous power failure or instantaneous voltage drop ends. For example, if the combustion of the combustion device provided in the hot water supply device is stopped during the hot water supply operation, it takes time to restart the combustion.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a hot water supply device that can continue operation even when an instantaneous power failure or instantaneous voltage drop occurs.

  To achieve the above object, a hot water supply apparatus according to an embodiment of the present invention includes a control device, a load device controlled by the control device, a power supply device that supplies DC power to the control device and the load device, The power supply device includes a smoothing capacitor that smoothes a voltage applied using an external power supply as a supply source to generate a DC voltage, and two switching elements each connected to the smoothing capacitor. And a load power supply unit that intermittently takes in the DC voltage by performing control to alternately conduct the two switching elements, generates a voltage obtained by stepping down the DC voltage, and supplies the voltage to the load device. A control power supply unit that is connected to the smoothing capacitor and generates a voltage obtained by stepping down the DC voltage and supplies the voltage to the control device. When switching of the switching elements is alternately conducted and when a decrease in the supply voltage of the external power supply is detected, one of the two switching elements is not conducted. Yes.

  According to this configuration, in the load power supply unit, when the two switching elements are controlled to be turned on alternately, when a decrease in the supply voltage of the external power source due to an instantaneous power failure or the like is detected, Any one of the switching elements is configured not to conduct. Therefore, consumption of the energy stored in the smoothing capacitor can be suppressed, and the rate of voltage decrease of the smoothing capacitor can be reduced. As a result, the holding time of the output voltage applied from the control power supply unit to the control device can be extended, and the operable time of the control device can be extended. Therefore, it is possible to continue the operation of the hot water supply device even if there is an instantaneous power failure or the like.

  The power supply device is supplied with an AC voltage from the external power supply, rectifies the AC voltage and supplies the AC voltage to the smoothing capacitor, and zero-cross detection that detects passage of a zero point of the AC voltage supplied to the rectifying unit. And the control device determines the presence or absence of a voltage drop of the AC voltage based on an output signal of the zero cross detection circuit, and the load power supply unit when the voltage drop of the AC voltage occurs. The load power supply unit is configured not to conduct any one of the two switching elements while the voltage drop detection signal is input. May be.

  According to this configuration, it is possible to continue the operation of the hot water supply device even when an instantaneous power failure occurs in the external power source.

  The control power supply unit includes a primary winding to which the DC voltage is intermittently applied, a secondary winding to which a voltage supplied to the control device is output, and a voltage applied to the primary winding. A switching transformer having an auxiliary winding for generating a voltage, and the load power supply unit when a voltage generated in the auxiliary winding in response to the DC voltage applied to the primary winding is less than a predetermined voltage. And a voltage drop detection circuit for outputting a voltage drop detection signal to the load power supply unit, while the voltage drop detection signal is being input, the load power supply unit conducts either one of the two switching elements. You may be comprised so that it may not be made.

  According to this configuration, it is possible to continue the operation of the hot water supply device even when an instantaneous power failure or instantaneous voltage drop occurs in the external power source.

  The present invention has the configuration described above, and provides an effect that it is possible to provide a hot water supply device that can continue operation even when an instantaneous power failure or instantaneous voltage drop occurs.

FIG. 1 is a diagram illustrating an example of a schematic configuration of a hot water supply apparatus according to the first and second embodiments. FIG. 2 is a block diagram illustrating a configuration example of the controller unit in the first embodiment. FIG. 3A is a diagram illustrating an example of an input voltage of the zero-cross detection circuit, FIG. 3B is a diagram illustrating an example of an output signal of the zero-cross detection circuit, and FIG. It is a figure which shows the other example of the output signal of a detection circuit. FIG. 4 is a diagram illustrating an example of a schematic configuration of the load power supply unit according to the first embodiment. FIG. 5 is a diagram illustrating an example of an on / off operation of two switching elements and a change over time of a terminal voltage of the smoothing capacitor in the load power supply unit. FIG. 6 is a block diagram illustrating a configuration example of a controller unit in the second embodiment. FIG. 7 is a diagram illustrating an example of a schematic configuration of a load power supply unit according to the second embodiment. FIG. 8 is a diagram illustrating an example of a schematic configuration of a control power supply unit according to the second embodiment.

  Hereinafter, preferred embodiments will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference symbols throughout all the drawings, and redundant description thereof is omitted. Further, the present invention is not limited to the following embodiment.

[First Embodiment]
(Configuration of hot water supply system)
First, with reference to FIG. 1, the principal part structure of the hot water supply apparatus which concerns on embodiment of this invention is demonstrated. FIG. 1 is a diagram illustrating an example of a schematic configuration of a hot water supply apparatus according to an embodiment of the present invention. The hot water supply device 1 is a multifunction hot water supply device having a hot water supply function for supplying hot water to a kitchen, a bathtub, or the like and a bath replenishment function. The hot water supply apparatus 1 may have a hot water heating function such as floor heating, or may have only a hot water supply function.

  As shown in FIG. 1, the hot water supply device 1 includes a combustion device 2 that burns fuel gas, a fuel gas supply path 21 that supplies fuel gas to the combustion device 2, a blower 22 that supplies air to the combustion device 2, A hot water supply channel 3, a reheating channel 4, a bath water pump 41 provided in the reheating channel 4, and a controller unit 5 are provided. The blower 22 and the bath water pump 41 are each provided with a DC motor as a drive unit.

  The combustion device 2 is provided with a burner portion 24, and fuel gas is supplied to the burner portion 24 from the fuel gas supply path 21. The fuel gas supply path 21 is provided with a source gas solenoid valve 25 that switches between supply and cutoff of the fuel gas, and a gas proportional valve 26 that adjusts the supply amount of the fuel gas. Further, the burner unit 24 is provided with a bath gas electromagnetic valve 30, a plurality of hot water supply capacity switching gas electromagnetic valves 28, and a hot water supply gas electromagnetic valve 29.

  The hot water supply flow path 3 exchanges heat between the water supplied from the water supply or the like from the water supply inlet 31 to the hot water supply side heat exchanging section 33 described later, and the combustion gas generated by the combustion device 2. It consists of piping that forms a hot water supply side heat exchange section 33 that heats and a return path section 35 that sends hot water from the hot water supply side heat exchange section 33 to the hot water supply outlet 34. The return path section 35 is provided with a hot water supply amount adjustment valve 36 for adjusting the hot water supply amount and a mixing valve 37 for adjusting the mixing ratio of water and hot water in order to adjust the amount and temperature of the hot water supply. As shown in FIG. 1, the forward path section 32 is provided with a bypass path that branches in the middle of the hot water supply side heat exchange section 33 and is connected to the mixing valve 37. It is configured so that a part of the water flowing in from the water can be guided to the mixing valve 37.

The reheating channel 4 is a reheating unit 43 that sends bath water from a return port 42 to a reheating side heat exchanging unit 44 to be described later, and a reheating unit that heats the bath water by exchanging heat with the combustion gas generated in the combustion device 2. It is comprised from the piping which forms the burning side heat exchange part 44 and the going part 46 which sends the heated bath water from the reheating side heat exchange part 44 to the going mouth 45. The bath water pump 41 is provided in the return portion 43 of the reheating channel 4.
In FIG. 1, various sensors such as an incoming water temperature sensor and a hot water temperature sensor in the hot water supply passage 3 are not shown. Further, in FIG. 1, illustration of a bathtub pouring path branched from the hot water supply flow path 3 and connected to the reheating flow path 4, and a pouring on / off valve provided in the bathtub pouring path is omitted. Yes.

  The controller unit 5 includes a control device 51 and a power supply device 6. The control device 51 includes a CPU, a ROM, a RAM, and the like, and can be realized by an integrated circuit such as a microcontroller. A signal path for controlling each electrical component such as the blower 22 and the bath water pump 41 is connected to the control device 51. In the control device 51, for example, the CPU can execute various controls of the hot water supply device 1 by reading the control program stored in the ROM into the RAM and executing it. The control program includes, for example, various programs related to operation control of each electrical component.

  The controller unit 5 is supplied with electric power from an AC power supply 11 (FIG. 2, FIG. 6) such as a commercial power supply, and the power supply device 6 generates electric power used in the hot water supply device 1. It is converted into a voltage as required by the power supply device 6 and supplied to each electrical component such as the control device 51, the combustion device 2, the blower 22, the bath water pump 41, various electromagnetic valves, and various sensors.

(Configuration of controller unit)
Next, the structure of the controller unit with which the hot water supply apparatus according to the first embodiment is provided will be described. FIG. 2 is a block diagram illustrating a configuration example of the controller unit 5 in the first embodiment.

  The controller unit 5 shown in FIG. 2 includes the control device 51 and the power supply device 6 as described above. The power supply device 6 includes a noise filter 61, a rectifying unit 62 including a diode bridge, a smoothing capacitor C1, a load power supply unit 63, a control power supply unit 64, and a zero cross detection circuit 65.

  An input terminal of the noise filter 61 is connected to, for example, an AC 100V AC power supply 11, and an AC voltage from which noise has been removed by the noise filter 61 is input to the rectifier 62 and rectified. The rectifier 62 is a full-wave rectifier circuit configured by, for example, a diode bridge. The output voltage of the rectifier 62 is smoothed by the smoothing capacitor C1 and output as the DC voltage V1. This DC voltage V <b> 1 is input to the load power supply unit 63 and the control power supply unit 64. The noise filter 61 also prevents the noise generated in the power supply device 6 from flowing out to the AC power supply 11 side.

  In the load power supply unit 63, the DC voltage V <b> 1 (for example, 140 V) is stepped down to generate a load driving DC voltage (for example, 47 V) and supplied to the motor 22 </ b> M of the blower 22.

  In the control power supply unit 64, the DC voltage V <b> 1 is stepped down to generate a voltage (for example, 15 V) that serves as a DC power supply for the control device, and supplies it to the control device 51.

  The zero-cross detection circuit 65 is a circuit that receives the AC voltage output from the noise filter 61 and detects the passage of the zero point of the AC voltage (crossing of the zero point), and includes a known circuit using a comparator or the like. can do. The zero cross detection circuit 65 outputs, for example, an L level (low level) immediately before and immediately after the input AC voltage (Vin) passes through the zero point, and outputs an H level (high level) otherwise. It is configured as follows. In this case, the AC voltage (Vin) input to the zero-crossing detection circuit 65 outputs an L level when −Vt ≦ Vin ≦ Vt, for example, when Vt is a predetermined positive threshold voltage, Other than that, it is configured to output H level.

  FIG. 3A is a diagram illustrating an example of the input voltage Vin of the zero-cross detection circuit 65, and FIG. 3B is a diagram illustrating an example of the output signal S1 of the zero-cross detection circuit 65, and FIG. ) Is a diagram showing another example of the output signal S1 of the zero-cross detection circuit 65. FIG. FIG. 3 shows a case where a power failure occurs in the AC power supply 11 at time t1.

  In the case of the output signal S1 in FIG. 3B, the zero-cross detection circuit 65 is configured to output the L level at the time when the input voltage Vin passes the zero point and immediately before and after that as described above. In this case, the passage of the zero point of the input voltage Vin is detected by the output signal S1 changing from the H level to the L level and further to the H level.

  On the other hand, the zero cross detection circuit 65 may be configured so as to be the output signal S1 of FIG. In this case, the zero cross detection circuit 65 is configured to output an L level when the input voltage Vin is a positive voltage and to output an H level when the input voltage Vin is a negative voltage. In this case, the passage of the zero point of the input voltage Vin is detected by changing the output signal S1 from the H level to the L level and from the L level to the H level.

  The output signal S1 of the zero cross detection circuit 65 is input to the control device 51. In the control device 51, based on the output signal S1 of the zero cross detection circuit 65, it is determined whether or not an AC voltage is input from the AC power source 11 (whether or not a power failure has occurred), and when it is determined that no power failure has occurred. An H level switching signal S2 is output to the load power source 63, and when it is determined that a power failure has occurred, the switching signal S2 is set to the L level. This L level switching signal S2 is a voltage drop detection signal. Note that the L level of the switching signal S2 includes the case of no signal state.

  In the case of the output signal S1 in FIG. 3B, when an AC voltage is normally input from the AC power supply 11 without a power failure, the output signal S1 of the zero cross detection circuit 65 is at the H level and the L level. Each of the repetition periods is ½ of the period T of the input voltage Vin. In this case, the control device 51 determines that a power failure has occurred when the level of the output signal S1 of the zero-cross detection circuit 65 is fixed for a predetermined time (for example, time T / 2). The switching signal S2 to the load power supply unit 63 is switched from the H level to the L level.

  On the other hand, in the case of the output signal S1 in FIG. 3C, when the AC voltage is normally input from the AC power supply 11 without a power failure, the H level of the output signal S1 of the zero cross detection circuit 65 is Each period of the L level is ½ of the period T of the input voltage Vin. In this case, the control device 51 performs a power failure when the level of the output signal S1 is fixed for a predetermined time longer than T / 2 (for example, longer than T / 2 and shorter than T). And the switching signal S2 to the load power supply unit 63 is switched from the H level to the L level.

FIG. 4 is a diagram illustrating an example of a schematic configuration of the load power supply unit 63 according to the first embodiment.
The load power supply unit 63 is connected to the terminal TV1 to which the smoothing capacitor C1 is connected, the drains of the two switching elements Q1 and Q2 are connected, and one end of the coil L1 is connected to the sources of the two switching elements Q1 and Q2. The other end of L1 is connected to the output terminal TV21 of the load power supply unit 63. One end of the coil L1 is connected to the cathode of the diode D1, and the anode of the diode D1 is connected to the ground GND and to the negative electrode of the capacitor C2. The positive electrode of the capacitor C2 is connected to the other end of the coil L1 and the output terminal TV21. These switching elements Q1, Q2, coil L1 (inductor), diode D1 (freewheeling diode) and capacitor C2 constitute a step-down chopper circuit. Further, here, a push-pull method is used in which the two switching elements Q1 and Q2 are alternately turned on (conductive), and the terminal voltage V1 of the smoothing capacitor C1 is obtained by alternately turning on the two switching elements Q1 and Q2. Is taken in intermittently.

  Here, the switching elements Q1 and Q2 are constituted by n-channel MOSFETs, and the ON / OFF operation thereof is controlled by the control circuit 71. Here, the switching elements Q1 and Q2 are configured to be turned on when the control signals S11 and S12 of the control circuit 71 are at the L level via the isolation transformers IT1 and IT2, and turned off when the control signals S11 and S12 are at the H level (however, , When a switching element Q3 described later is in an ON state).

  For this purpose, the source of the switching element Q1 is connected to one end of the secondary winding P12 of the insulating transformer IT1, the gate of the switching element Q1 is connected to the other end of the secondary winding P12 via the resistor r2, and the switching element Q1. A resistor r1 is connected between the gate and the source. Similarly, the source of the switching element Q2 is connected to one end of the secondary winding P22 of the insulation transformer IT2, and the gate of the switching element Q2 is connected to the other end of the secondary winding P22 via the resistor r4. A resistor r3 is connected between the gate and the source.

  One end of the primary winding P21 of the insulation transformer IT2 is connected to the output terminal of the control signal S12 of the control circuit 71, and the other end of the primary winding P21 is connected to the ground via the diode D3. A capacitor C4 is connected between the intermediate point of the primary winding P21 and the anode of the diode D3, and a power supply terminal TV22 is connected to the electrode of the capacitor C4 connected to the intermediate point of the primary winding P21.

  When the control signal S12 is at the H level, the capacitor C4 is charged by the DC voltage V22 (for example, 12V) applied to the power supply terminal TV22. When the control signal S12 is at the L level, the current discharged from the capacitor C4 is the primary winding. It flows from the intermediate point of P21 toward one end, and further flows into the control circuit 71 through the wiring of the control signal S12. At this time, when a current flows through the primary winding P21, an H level voltage is applied to the gate of the switching element Q2 connected to the secondary winding P22, and the switching element Q2 is turned on. On the other hand, when the control signal S12 is at the H level, no current flows through the primary winding P21, so that the switching element Q2 is turned off.

  One end of the primary winding P11 of the insulation transformer IT1 is connected to the output terminal of the control signal S11 of the control circuit 71, and the other end of the primary winding P11 is connected to the ground via the diode D2. Further, a switching element Q3 and a capacitor C3 are connected in series between the intermediate point of the primary winding P11 and the anode of the diode D2, and the power supply terminal TV22 is connected to the electrode of the capacitor C3 connected to the source of the switching element Q3. Is connected.

  The switching element Q3 is composed of a p-channel MOSFET, and its source and gate are connected via a resistor r6, and its gate is connected to a phototransistor of the photocoupler PC1 via a resistor r5. Both ends of the light emitting diode of the photocoupler PC1 are connected via a resistor r7, the cathode of the light emitting diode is connected to the ground, and the switching signal S2 from the control device 51 is input to the anode. The ground to which the resistor r7 is connected is a circuit ground on the low voltage side.

  Here, when the switching signal S2 is at the H level, the phototransistor of the photocoupler PC1 is turned on and the switching element Q3 is turned on. When the switching element Q3 is on, when the control signal S11 is at the H level, the capacitor C3 is charged by the DC voltage V22 applied to the power supply terminal TV22, and when the control signal S11 becomes the L level, the capacitor C3 The discharged current path flows from the intermediate point of the primary winding P11 toward one end, and further flows into the control circuit 71 through the wiring of the control signal S11. At this time, when a current flows through the primary winding P11, an H level voltage is applied to the gate of the switching element Q1 connected to the secondary winding P12, and the switching element Q1 is turned on. On the other hand, when the control signal S11 is at the H level, no current flows through the primary winding P11, so that the switching element Q1 is turned off.

  When the switching signal S2 is at the L level, the phototransistor of the photocoupler PC1 is off and the switching element Q3 is also off. In this case, the capacitor C3 is charged by the DC voltage V22, but even if the control signal S11 becomes L level, the current path discharged from the capacitor C3 is interrupted by the switching element Q3 in the off state, so that the primary winding The current does not flow through the line P11, and the switching element Q1 is kept off. That is, when the switching signal S2 from the control device 51 is at the L level, the switching element Q1 is turned off regardless of the control of the control circuit 71.

  The power supply terminal TV22 is connected to the power supply input terminal of the control circuit 71, and is connected to the ground together with the ground terminal of the control circuit 71 via the capacitor C5. The DC voltage V22 applied to the power supply terminal TV22 is generated by a circuit (not shown) in the control power supply unit 64, for example.

  The voltage V21 of the output terminal TV21 of the load power supply unit 63 is supplied to the motor 22M of the blower 22.

  Although not shown, a rotation speed detection sensor that detects the rotation speed of the motor 22M is attached to the motor 22M of the blower, and a detection signal of the rotation speed detection sensor is input to the control device 51. The control device 51 outputs a control signal for maintaining the rotational speed of the motor 22M to a predetermined value based on the detection signal of the rotational speed detection sensor to the control circuit 71. The control circuit 71 outputs based on the control signal. The on / off control of the switching elements Q1 and Q2 is performed so that the voltage V21 of the terminal TV21 becomes a desired DC voltage (for example, 47V).

  FIG. 5 is a diagram illustrating an example of the on / off operation of the two switching elements Q1 and Q2 in the load power supply unit 63 and the temporal change of the terminal voltage V1 of the smoothing capacitor C1. FIG. 5 shows a case where a power failure occurs in the AC power supply 11 at time t11.

  When the power failure before time t11 has not occurred, the switching signal S2 is at the H level and the switching element Q3 is maintained in the on state, and the two switching elements Q1, Q2 are controlled by the control signals S11, S12 of the control circuit 71. An operation by a push-pull method for alternately turning on (conducting) is performed.

  For example, when a power failure occurs at time t11 and the control device 51 determines that a power failure has occurred based on the output signal S1 of the zero-cross detection circuit 65, the switching signal S2 is switched from the H level to the L level. When the switching signal S2 becomes L level, the switching element Q3 is turned off and the switching element Q1 is turned off. That is, the control circuit 71 outputs the control signals S11 and S12 for performing the operation by the push-pull method, but the switching element Q1 is maintained in the off state, and the single method in which only one switching element Q2 operates. It becomes the operation state.

  After the power failure occurs, the energy stored in the smoothing capacitor C1 is consumed. As shown in FIG. 5, the voltage V1 of the smoothing capacitor C1 (the voltage at the terminal TV1) decreases and the energy stored in the smoothing capacitor C1 is reduced. 0 when no longer exists.

  On the other hand, when the switching element Q1 is not turned off by the switching signal S2, the operation by the push-pull method in which the two switching elements Q1 and Q2 are alternately turned on is continued, so that the switching method is switched to the single method as in this embodiment. Compared to the case, the consumption speed of the stored energy of the smoothing capacitor C1 is large, and the decreasing speed of the voltage V1 of the smoothing capacitor C1 is large.

  In the present embodiment, when the power failure occurs, the rate of decrease of the voltage V1 of the smoothing capacitor C1 can be reduced by switching from the push-pull method to the single method. As a result, it is possible to extend the holding time of the output voltage supplied from the control power supply unit 64 to the control device 51 by consuming the energy stored in the smoothing capacitor C1, and to extend the operable time of the control device 51.

  For example, when a hot-power supply operation is performed and there is an instantaneous power failure of 100 ms, and the operation by the push-pull method is continued, the holding time (control of the output voltage of the control power supply unit 64 from the time of the power failure occurs) The time until the operation of the device 51 stops was 90 ms. When the hold time of the output voltage of the control power supply unit 64 is increased to 110 ms by switching from the push-pull method to the single method, an instantaneous power failure of 100 ms The control device 51 is operating even at the end of. Thus, even if there is an instantaneous power failure, the control device 51 such as a microcomputer can continue to operate, and the operation of the hot water supply device 1 can be continued.

  Further, as described above, a detection signal of a rotation number detection sensor (not shown) of the motor 22M of the blower 22 is input to the control device 51. When the driving voltage of the motor 22M supplied from the load power supply unit 63 is remarkably lowered during the hot water supply operation, and the rotational speed of the motor 22M becomes less than a predetermined value, the control device 51 performs an abnormal process (for example, combustion) When the instantaneous power failure occurs as described above in the case where the operation of the hot water supply device is stopped by stopping the combustion of the device 2, smoothing is performed by switching from the push-pull method to the single method. Since the decrease rate of the voltage V1 of the capacitor C1 can be reduced and the decrease rate of the output voltage of the load power supply 63 (the drive voltage of the motor 22M) can be reduced, the control device 51 performs an abnormal process to perform the hot water supply device 1 The operation of the hot water supply device 1 can be continued without stopping the operation.

[Second Embodiment]
The configuration example of the hot water supply apparatus according to the second embodiment is the same as that of the first embodiment, and is shown as in FIG. 1, for example. The present embodiment is different from the first embodiment in the internal configuration of the controller unit 5.

(Configuration of controller unit)
Next, the structure of the controller unit with which the hot water supply apparatus which concerns on 2nd Embodiment is provided is demonstrated. FIG. 6 is a block diagram illustrating a configuration example of the controller unit 5 in the second embodiment.

  The controller unit 5 includes the control device 51 and the power supply device 6 as described above. The power supply device 6 includes a noise filter 61, a rectifying unit 62 including a diode bridge, a smoothing capacitor C1, a load power supply unit 63, and a control power supply unit 64, and does not include the zero cross detection circuit 65 in the first embodiment. .

  FIG. 7 is a diagram illustrating an example of a schematic configuration of the load power supply unit 63 according to the second embodiment. 7 is provided with a transistor Tr1 instead of the photocoupler PC1 in FIG. Other configurations are the same as those in FIG. A switching signal S3 is input from the control power supply unit 64 to the base of the transistor Tr1.

  FIG. 8 is a diagram illustrating an example of a schematic configuration of the control power supply unit 64 according to the second embodiment. The control power supply unit 64 in the second embodiment is provided with a switching signal generation circuit (voltage drop detection circuit) 73. In the case of the control power supply unit 64 in the first embodiment described above, the switching signal generation circuit 73 can be eliminated from the control power supply unit 64 shown in FIG.

  8 is a circuit that steps down the DC voltage V1 rectified and smoothed by the rectifier 62 and the smoothing capacitor C1 to a predetermined DC voltage V23 (for example, 15 V) that serves as the power supply voltage of the control device 51. And a DC-DC converter using the switching transformer ST1. In the control power supply unit 64, the switching transformer ST1 electrically insulates and separates the primary side high voltage V1 from the secondary side voltage V23 supplied to the control device 51. The switching transformer ST1 has a primary winding P1, a secondary winding P2, and an auxiliary winding S.

  The primary winding P1 has one end connected to the smoothing capacitor C1, the other end connected to the switching element Q11 and the capacitor C11 connected in parallel, and further connected to the ground GND via the resistor r11. The switching element Q11 has a gate connected to the control circuit 72 via the coil L11, resistors r13 and r14, and a diode D11, and is on / off controlled by a control pulse from the control circuit 72. That is, the control circuit 72 sets the duty ratio of the control pulse for turning on or off the switching element Q11. Here, the switching element Q11 is composed of an n-channel MOSFET.

  Then, the control circuit 72 changes the duty ratio of the control pulse based on a feedback voltage (this feedback circuit is not shown) given from the output side of the switching transformer ST1, thereby causing a voltage on the output side of the switching transformer ST1. Feedback control is performed so that (the voltage of the secondary winding P2 and the auxiliary winding S) becomes a desired voltage. Although not shown, the control circuit 72 is connected to one output line of the noise filter 61 via a resistor and a diode. When the output potential of one output of the noise filter 61 rises, the control circuit 72 receives power from the AC power supply 11. It is started at the time of power-on when supply is started.

  The secondary winding P2 has one end connected to the output terminal TV23 via the diode D14 and the smoothing reactor L12, and the other end connected to the ground. Further, smoothing capacitors C15 and C16 are connected between both ends of the smoothing reactor L12 and the ground. The ground to which the capacitors C15 and C16 are connected is a circuit ground on the low voltage side.

  In the control power supply unit 64, the DC voltage V23 obtained by stepping down the input voltage V1 to a predetermined voltage (for example, 15V) through the primary winding P1 and the secondary winding P2 of the switching transformer ST1 is output to the output terminal TV23. Then, the data is input from the output terminal TV 23 to the control device 51.

  One end of the auxiliary winding S is connected to the control power supply terminal TVcc via the resistor r15 and the diode D12. The control power supply terminal TVcc is connected to the power supply input terminal of the control circuit 72, and is connected to the ground GND together with the ground terminal of the control circuit 72 via capacitors C12 and C13 connected in parallel. A predetermined DC voltage Vcc (for example, 20 V) obtained by stepping down the input voltage V1 is applied to the control power supply terminal TVcc through the primary winding P1 and the auxiliary winding S. The voltage Vcc is the power supply voltage of the control circuit 72. It becomes.

  Further, a switching signal generation circuit 73 is connected to the auxiliary winding S. Here, one end of the auxiliary winding S is connected to the voltage dividing resistors r16 and r17 via the diode D13, and the capacitor C14 is connected in parallel with the voltage dividing resistors r16 and r17 between one end and the other end of the auxiliary winding S. And the other end of the auxiliary winding S is connected to the ground.

  A resistor r18 and a Zener diode 75 are connected in series between the control power supply terminal TVcc and the other end of the auxiliary winding S, and the cathode of the Zener diode 75 is connected to the inverting input terminal of the operational amplifier 74. The connection point of the resistors r16 and r17 is connected to the non-inverting input terminal of the operational amplifier 74. The output terminal of the operational amplifier 74 is connected to the base of the transistor Tr1 of the load power supply unit 63 via the resistor r19.

  In the switching signal generation circuit 73, when the voltage Vr divided by the voltage dividing resistors r16 and r17 is higher than the reference voltage (input voltage of the inverting input terminal of the operational amplifier 74) Vs, the switching signal generation circuit 73 is at the H level for turning on the transistor Tr1. When the switching signal S3 is output and the divided voltage Vr is smaller than the reference voltage Vs, an L level switching signal S3 for turning off the transistor Tr1 is output. This L level switching signal S3 is a voltage drop detection signal.

  Since the voltage of the auxiliary winding S varies according to the variation of the input voltage V1 applied to the primary winding P1, the voltage Vr obtained by dividing the voltage of the auxiliary winding S also varies according to the variation of the input voltage V1. To do. Therefore, when a normal AC voltage is supplied from the AC power supply 11 and the input voltage V1 is within the normal range, the divided voltage Vr becomes higher than the reference voltage Vs, and the AC power supply 11 is interrupted, When the AC voltage supplied from the power supply 11 is abnormally lowered and the input voltage V1 becomes an abnormally low voltage below the lower limit (predetermined voltage) of the normal range, the divided voltage Vr is higher than the reference voltage Vs. The resistance values of the voltage dividing resistors r16 and r17 are set to be low.

  When a power failure or instantaneous voltage drop occurs in the AC power supply 11, the switching signal S3 is switched from the H level to the L level, and the transistor Tr1 of the load power supply unit 63 is turned off.

  In the load power supply unit 63 shown in FIG. 7, when the transistor Tr1 is turned off, the switching element Q3 is turned off, and the push-pull operation is switched to the single operation as described in the first embodiment.

  In the second embodiment, the same effect as in the first embodiment can be obtained. In the case of the second embodiment, not only in the case of an instantaneous power failure, but also in the case of an instantaneous voltage drop, the operation of the water heater 1 can be continued by switching from the push-pull method operation to the single method operation. It becomes possible.

  In the second embodiment, instead of the AC power supply 11, a DC voltage may be supplied from the DC power supply using a solar power generation system or the like to the smoothing capacitor C1. In this case, the noise filter 61 and the rectifying unit 62 are unnecessary.

  In the first and second embodiments, instead of the switching element Q3 (FIGS. 4 and 7) of the load power supply unit 63, an element that can be switched on (conductive) and off (cut off) such as a relay is used. May be.

  As the hot water supply apparatus to which the present invention can be applied, in addition to a gas combustion heating type hot water supply apparatus, an oil combustion heating type, a heat pump heating type, a type using solar heat, a type using an electric heater, and a power generation device There are various types of hot water supply devices such as those of a cogeneration system that uses exhaust heat of a fuel cell or a gas engine.

  From the foregoing description, many modifications and other embodiments of the present invention are obvious to one skilled in the art. Accordingly, the foregoing description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and / or function may be substantially changed without departing from the spirit of the invention. For example, the circuit configuration and control method for switching between the push-pull method and the single method are not limited to those of the above-described embodiment.

  INDUSTRIAL APPLICABILITY The present invention is useful as a hot water supply device that can continue operation even when an instantaneous power failure or instantaneous voltage drop occurs.

C1 Smoothing capacitor Q1, Q2 Switching element ST1 Switching transformer P1 Primary winding P2 Secondary winding S Auxiliary winding 6 Power supply 11 AC power supply 22 Blower (an example of load equipment)
51 Control Device 63 Power Supply Unit for Load 64 Power Supply Unit for Control 65 Zero Cross Detection Circuit 73 Switching Signal Generation Circuit (Voltage Drop Detection Circuit)

Claims (3)

A hot water supply apparatus comprising: a control device; a load device controlled by the control device; and a power supply device that supplies direct current power to the control device and the load device,
The power supply device
A smoothing capacitor that generates a DC voltage by smoothing a voltage applied using an external power supply as a supply source;
Each of the two switching elements connected to the smoothing capacitor has a voltage obtained by stepping down the DC voltage by intermittently taking in the DC voltage by controlling the two switching elements alternately. A load power supply unit that generates and supplies the load device;
A control power supply unit connected to the smoothing capacitor and generating a voltage obtained by stepping down the DC voltage and supplying the voltage to the control device;
The load power supply unit
When performing a control for alternately turning on the two switching elements, if any drop in the supply voltage of the external power supply is detected, do not turn on one of the two switching elements. Configured,
Hot water supply device. The power supply device
An AC voltage is supplied from the external power source, a rectifying unit that rectifies the AC voltage and supplies the AC voltage to the smoothing capacitor;
A zero-cross detection circuit that detects passage of a zero point of the AC voltage supplied to the rectifying unit;
The controller is
Based on the output signal of the zero cross detection circuit, the presence or absence of a voltage drop of the AC voltage is determined, and when there is a voltage drop of the AC voltage, a voltage drop detection signal is output to the load power supply unit,
The load power supply unit
While the voltage drop detection signal is input, it is configured not to conduct any one of the two switching elements,
The hot water supply apparatus according to claim 1. The control power supply unit
A primary winding to which the DC voltage is intermittently applied; a secondary winding to which a voltage to be supplied to the control device is output; and an auxiliary winding for generating a voltage corresponding to the voltage applied to the primary winding. A switching transformer having a line;
A voltage drop detection circuit for outputting a voltage drop detection signal to the load power supply unit when a voltage generated in the auxiliary winding in response to the DC voltage applied to the primary winding is less than a predetermined voltage. And
The load power supply unit
While the voltage drop detection signal is input, it is configured not to conduct any one of the two switching elements,
The hot water supply apparatus according to claim 1.

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