JP2010279103A - Power supply device and power consumption measurement system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device and a power consumption measurement system wherein a configuration for measuring power consumption is insusceptible to a voltage of an external power source and an increase in size is less prone to be incurred. <P>SOLUTION: The power supply device includes: a direct-current power supply unit 1 that converts power inputted from an external alternating-current power source AC into direct-current power of a predetermined voltage and outputs it; a power conversion unit 2 that converts direct-current power inputted from the direct-current power supply unit 1 and supplies it to a discharge lamp FL; a first resistor R1 that generates higher detection voltage V1 with an increase in the current passed through a switching element Q2 of the power conversion unit 2; and a computation unit 41 that computes power consumption using the detection voltage V1. The detection voltage V1 generated at the first resistor R1 that is located in the stage subsequent to the direct-current power supply unit 1 and is insusceptible to a difference in the power of the alternating-current power source AC is used for the computation of power consumption. Therefore, an error caused by a difference in the power of the alternating-current power source AC is suppressed. In addition, an increase in size is less prone to be incurred as compared with cases where a current transformer is used. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply device and a power consumption measurement system.

  Conventionally, there has been provided a power supply device that appropriately converts power supplied from an external power source and supplies the power to a load, and detects power consumption and notifies the outside (see, for example, Patent Document 1 and Patent Document 2). ).

  Further, in this type of power supply device, there is provided a device that measures and notifies power consumption. The measurement result of the power consumption obtained from such a power supply device can be used by the user for power saving. As a method for measuring power consumption, for example, there is a method using a current transformer.

Japanese Utility Model Publication No. 64-13695 Japanese Patent No. 3947139

  However, using a current transformer leads to an increase in size.

  In recent years, a power supply device that can use a plurality of types of power supplies such as a 100 V power supply and a 200 V power supply as an external power supply has been provided. However, in a method of detecting power consumption, there is a change in actual power consumption. Even if the voltage of the external power source changes as described above, the power consumption as a detection result may change.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described reasons, and an object of the present invention is to provide a power supply device and a power consumption measurement system in which a configuration for measuring power consumption is not easily affected by the voltage of an external power supply and does not easily increase in size. Is to provide.

  The invention of claim 1 includes a DC power supply unit that converts electric power input from an external power source into DC power of a predetermined voltage and outputs the DC power, and at least one switching element, and the DC power input from the DC power supply unit A power conversion unit that appropriately converts the current to supply to the load, a current detection unit that generates an output that shows a higher value as the current flowing through the switching element of the power conversion unit increases, an output value Vs of the current detection unit, and a constant A calculation unit that calculates power consumption Win by the expression Win = α × Vs + β using α and β, and a notification unit that notifies the power consumption Win calculated by the calculation unit to the outside are provided.

  According to the present invention, since the power input from the external power source is once converted into DC power of a predetermined voltage by the DC power source unit, the output of the current detection unit at the subsequent stage of the DC power source unit is input from the external power source. In the power consumption obtained by the calculation using the output of the current detection unit, an error due to the difference in power input from an external power source can be suppressed. In addition, since the current detection unit can be configured by a resistor connected in series to the switching element, it is less likely to increase in size compared to the case where a current transformer is used.

  The invention according to claim 2 includes at least one switching element, a power converter that appropriately converts DC power input from an external DC power source and supplies the power to the load, and a current flowing through the switching element of the power converter. A current detection unit that generates an output that indicates a higher value as the number increases, a power supply voltage detection unit that detects an input voltage from an external DC power supply to the power conversion unit, and a plurality of constants α and β used for calculating power consumption Win A storage unit that is stored in association with the range of the input voltage detected by the power supply voltage detection unit, and outputs the value Vs of the output of the current detection unit and the input voltage detected by the power supply voltage detection unit. In response, the constants α and β read from the storage unit are used to calculate the power consumption Win by the equation Win = α × Vs + β, and the power consumption Win calculated by the calculation unit is externally output. Characterized in that it comprises a notification unit that knowledge.

  According to the present invention, the constants α and β corresponding to the input voltage detected by the power supply voltage detection unit are used for the calculation of power consumption, so that the difference in input voltage, that is, the difference in power input from an external power supply is obtained. The resulting error is suppressed.

  According to a third aspect of the present invention, in the first aspect of the present invention, the DC power supply unit is one in which any of a plurality of types of power is selectively input, and the type of power input to the DC power supply unit is determined. A plurality of constants α and β used for calculating the power consumption Win, each of which is stored in association with the type of power determined by the input determining unit. When calculating the power consumption Win, constants α and β corresponding to the type of power determined by the input determining unit are read from the storage unit and used for the calculation.

  According to the present invention, it is possible to suppress errors caused by differences in the types of power input to the DC power supply unit.

  According to a fourth aspect of the present invention, in the first aspect of the invention, an instruction input unit to which an instruction for output power is input is provided, and the power conversion unit increases or decreases the output power in accordance with the instruction input to the instruction input unit. A plurality of constants α and β used for calculation of power consumption Win, each of which is stored in association with the range of output power of the power conversion unit, and the calculation unit calculates the power consumption Win When performing the calculation, constants α and β corresponding to the output power of the power conversion unit are read from the storage unit and used for the calculation.

  According to the present invention, errors caused by fluctuations in output power of the power conversion unit can be suppressed.

  According to a fifth aspect of the present invention, in the first aspect of the invention, the power conversion unit can execute a plurality of types of operations in which the relationship between the output value Vs of the current detection unit and the power consumption Win is different. A plurality of types of constants α and β used for the calculation of Win are provided, each of which is stored in association with the type of operation of the power conversion unit, and when the calculation unit calculates the power consumption Win, the power conversion unit The constants α and β corresponding to the type of operation performed by the are read from the storage unit and used for the calculation.

  According to the present invention, it is possible to suppress errors due to differences in the types of operations of the power conversion unit.

  A sixth aspect of the present invention is the first aspect of the present invention, wherein, in the first aspect of the present invention, a temperature detector that detects the temperature, and a plurality of constants α and β used for calculating the power consumption Win, each of the temperatures detected by the temperature detector. And a storage unit stored in association with the range. When calculating the power consumption Win, the calculation unit reads constants α and β corresponding to the temperature detected by the temperature detection unit from the storage unit and uses them in the calculation. It is characterized by that.

  According to the present invention, errors due to temperature differences can be suppressed.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the current detector includes an analog current detector that outputs a higher analog voltage as the current flowing through the switching element of the power converter increases, and a voltage value A / D-converts and outputs a periodic signal generator that generates a periodic signal that is an analog voltage that periodically changes across both the positive and negative sides, and a voltage in which the periodic signal is superimposed on the output voltage of the analog current detector A plurality of measurement timings selected so that the sum of contributions of the output voltage of the periodic signal generation unit to the input voltage to the A / D conversion unit and the A / D conversion unit is 0 for each predetermined measurement period. And a cumulative addition unit that obtains the value Vs of the output to the arithmetic unit as a value obtained by summing the values of the outputs of the A / D conversion unit obtained respectively. To do.

  According to the present invention, the difference occurring in the result of A / D conversion due to the superimposition of the periodic signal before A / D conversion as a whole cancels the quantization error caused by the A / D conversion. As a result, the quantization error is suppressed as a result.

  The invention of claim 8 is that in the invention of claim 7, the measurement period extends over a plurality of periods of the periodic signal, and the relationship between the phase of the periodic signal and the measurement timing is shifted for each period of the periodic signal. Features.

  The invention of claim 9 is the invention of claim 8, wherein the length of the measurement period is (p + 1 / q) using the length T of one period of the periodic signal, the natural number p of 2 or more, and the natural number q. The number of measurement timings in one measurement period is expressed as p × q, and for each i where 1 ≦ i ≦ p × q, an integer m = (i−1) / q The time from the start of the measurement period to the i-th measurement timing is expressed as (T / q) × (i−1) + m × T / (p × q) using (rounded down). And

  According to the present invention, the interval between the measurement timings is T / (p × q) when the relationship between the measurement timing and the phase of the periodic signal is taken as a whole while the interval between the actual measurement timings is set to T / q or more. It becomes the same as that.

  The invention of claim 10 includes a DC power source that converts power input from an external power source into DC power having a predetermined voltage and outputs the DC power, and at least one switching element, and that receives DC power input from the DC power source. A power converter that converts the current appropriately and supplies it to the load, an analog current detector that outputs a higher analog voltage as the current flowing through the switching element of the power converter increases, and the voltage value periodically changes across both positive and negative sides A periodic signal generation unit that generates a periodic signal that is an analog voltage to be output, an A / D conversion unit that performs A / D conversion and outputs a voltage in which the periodic signal is superimposed on the output voltage of the analog current detection unit, and predetermined measurement For each period, each A / D is measured at n (n ≧ 2) measurement timings selected so that the total contribution of the output voltage of the periodic signal generator to the input voltage to the A / D converter is zero. Strange Together give D a (i) output parts, the following equation using the sum and constants alpha, and β output D obtained by the entire measurement period (i)

And a cumulative calculation unit that calculates the power consumption Win, and a notification unit that notifies the power consumption Win calculated by the calculation unit to the outside.

  According to the present invention, since the power input from the external power source is once converted into DC power of a predetermined voltage by the DC power source unit, the output voltage of the current detection unit at the subsequent stage of the DC power source unit is input from the external power source. Since the power consumption obtained by the calculation using the output voltage of the current detection unit is less susceptible to the difference in power that is input, errors due to the difference in power input from an external power source can be suppressed. In addition, since the current detection unit can be configured by a resistor connected in series to the switching element, it is less likely to increase in size compared to the case where a current transformer is used. Furthermore, the difference that occurs in the result of A / D conversion due to the superimposition of the periodic signal before A / D conversion as a whole cancels the quantization error that occurs with A / D conversion. As a result, the quantization error is suppressed.

  An eleventh aspect of the invention is characterized in that, in any one of the first to tenth aspects of the invention, the DC power supply unit converts the input AC power into DC power.

  According to a twelfth aspect of the present invention, in the invention according to the first aspect or the third to sixth aspects, the DC power supply unit includes a diode bridge that full-wave rectifies AC power input from an external AC power supply, and a switching power supply. And a DC-DC converter that converts the output power of the diode bridge into DC power of a predetermined voltage and outputs it, and the current detection unit outputs an analog voltage that increases as the current flowing through the switching element of the power conversion unit increases. A current detector, an A / D converter for A / D converting and outputting a voltage in which a periodic signal is superimposed on the output voltage of the analog current detector, and an output voltage of the analog current detector for each predetermined measurement period A / D at each of n (n ≧ 2) measurement timings selected so that the total contribution of ripple components of the output of the DC-DC converter to 0 is zero It comprises an accumulating unit that obtains an output D (i) of the conversion unit and uses a value obtained by summing up the obtained output values of the A / D conversion unit as a value Vs of an output to the arithmetic unit. .

  According to the present invention, the error caused by the ripple component of the output of the DC-DC converter and the quantization error due to the A / D conversion in the A / D conversion unit are canceled each other, thereby being suppressed.

  A thirteenth aspect of the invention is characterized in that, in any one of the first to twelfth aspects of the invention, the load connected to the power converter is a light source.

  The invention according to claim 14 is provided with the power supply device according to any one of claims 1 to 13 and the power consumption transmitted from the power supply device, comprising a communication unit as a notification unit for transmitting data indicating power consumption. And a display device having a display unit for displaying the power consumption indicated in the data received by the communication unit.

  According to a fifteenth aspect of the present invention, in the fourteenth aspect of the present invention, the communication unit of the power supply device transmits the number obtained by dividing the power consumption calculated by the calculation unit by a predetermined unit power and rounded down as data indicating the power consumption. The display unit of the display device displays power consumption obtained by multiplying the number obtained from the data received by the communication unit by unit power.

  According to the present invention, the data load can be reduced and the communication load can be reduced as compared with the case where the power consumption value is directly transmitted as digital data as the data indicating the power consumption.

  According to the first and tenth aspects of the present invention, since the power input from the external power source is once converted into DC power of a predetermined voltage by the DC power source unit, the output of the current detection unit at the subsequent stage of the DC power source unit Is less susceptible to the difference in power input from the external power supply, so the power consumption obtained by the calculation using the output of the current detection unit suppresses errors due to the difference in power input from the external power supply. It is done. In addition, since the current detection unit can be configured by a resistor connected in series to the switching element, it is less likely to increase in size compared to the case where a current transformer is used. According to the invention of claim 10, the difference that occurs in the result of the A / D conversion due to the superimposition of the periodic signal before the A / D conversion is, as a whole, a quantization error that occurs due to the A / D conversion. As a result, the quantization error is suppressed.

  According to the second aspect of the present invention, the constants α and β corresponding to the input voltage detected by the power supply voltage detector are used for calculating the power consumption, so that the difference between the input voltages, that is, the power input from the external power supply. Errors due to the difference between the two are suppressed.

It is a circuit block diagram which shows Embodiment 1 of this invention. It is explanatory drawing which shows the relationship between detection voltage V1 and power consumption Win in the same as the above. It is a circuit block diagram which shows the example of a change same as the above. It is a circuit block diagram which shows another example of a change same as the above. It is a circuit block diagram which shows Embodiment 2 of this invention. It is a circuit block diagram which shows Embodiment 3 of this invention. It is explanatory drawing which shows operation | movement same as the above. It is explanatory drawing which shows operation | movement of the comparative example same as the above. It is explanatory drawing which shows operation | movement of the example of a change same as the above. It is explanatory drawing which shows operation | movement of another modified example same as the above. It is a circuit block diagram which shows Embodiment 4 of this invention. It is a block diagram which shows an example of a power consumption measuring system.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
In the present embodiment, as shown in FIG. 1, AC power is supplied to a hot cathode discharge lamp FL as a load for lighting, and the AC power input from an external AC power supply AC is fully waved. A diode bridge DB that rectifies, a DC-DC converter 10 that converts output power of the diode bridge DB into DC power of a predetermined voltage Vdc, and two switching elements Q1, connected between output terminals of the DC-DC converter 10. Connected between the switching unit 21 composed of a series circuit of Q2 and the first resistor R1, and the connection point between the two switching elements Q1, Q2 of the switching unit 21 and the output terminal on the low voltage side of the DC-DC converter 10 Then, the resonance unit 22 that forms a resonance circuit together with the discharge lamp FL and the two switching elements Q1 and Q2 of the switching unit 21 are alternately turned on and off. And a section 20. The DC-DC converter 10 and the diode bridge DB constitute a DC power supply unit 1 that converts AC power input from the AC power supply AC into DC power of a predetermined voltage Vdc. In addition, the switching unit 21 and the resonance unit 22 constitute a power conversion unit that is formed of a so-called half-bridge type inverter circuit and converts DC power output from the DC power supply unit 1 into AC power. Furthermore, the potential at the connection point between the first resistor R1 and the switching element Q2 is proportional to the current flowing through the switching unit Q2.

  The DC-DC converter 10 includes, for example, a well-known boost converter (step-up chopper circuit) having an output capacitor C10 and using the voltage Vdc across the output capacitor C10 as an output voltage so that the output voltage Vdc is a predetermined target voltage. Is feedback controlled. In general, when a switching power supply such as the above-described boost converter is used, the power factor is improved as compared with the case where the output capacitor C10 is directly connected between the output terminals of the diode bridge DB.

  Moreover, this embodiment has the instruction | indication input part 31 which receives the input which instruct | indicates the light output of the discharge lamp FL. The input to the instruction input unit 31 may be, for example, an electrical signal transmitted via a transmission line, or may be transmitted / received by a wireless signal using radio waves or infrared light as a medium, for example. An operation input may be used. In any case, since the instruction input unit 31 can be realized by a well-known technique, detailed illustration and description thereof are omitted.

  The controller 20 performs a preheating operation for preheating each filament of the discharge lamp FL at the time of starting, and then performs a starting operation for starting the lighting of the discharge lamp FL, and then maintains the lighting of the discharge lamp FL. Transition to steady operation. In addition, during the steady operation, the control unit 20 resonates the resonance unit 22 based on the potential at the connection point between the first resistor R1 and the switching element Q2 and the power corresponding to the instruction input to the instruction input unit 31. Is set to at least one of a frequency for turning on / off the switching elements Q1 and Q2 of the switching unit 21 and an on-duty so that the power output to the discharge lamp FL is the power corresponding to the instruction input to the instruction input unit 31. Feedback control.

  In addition, a detection capacitor C1 having one end connected to the ground and the other end connected to a connection point between the first resistor R1 and the switching element Q2 via the second resistor R2 is provided. That is, the voltage V1 across the detection capacitor C1 is a voltage corresponding to the current flowing through the switching element Q2 on the low side (low voltage side) of the switching unit 21, and the first resistor R1, the second resistor R2, and the detection The capacitor C1 constitutes the current detection unit in the claims. Since the average value of the current flowing through one switching element Q1 of the switching unit 21 and the average value of the current flowing through the other switching element Q2 are substantially equal to each other, the voltage V1 across the detection capacitor C1 is the high side (high voltage side). ) Reflecting the current flowing through the switching element Q1, that is, the power input to the power converter 2.

  Furthermore, the present embodiment includes a calculation unit 41 that calculates power consumption based on the voltage across the detection capacitor C1, and a notification unit 42 that notifies the power consumption calculated by the calculation unit 41 to the outside. Since the calculation unit 41 can be realized by a known technique using an electronic circuit, detailed illustration and description thereof are omitted.

  For example, the notification unit 42 may be a display unit that displays power consumption, or may be a communication unit that notifies power consumption to an external device that displays power consumption. As the display means, a known display device such as a 7-segment light emitting diode or a liquid crystal display can be used. Moreover, as a communication means, what transmits an electrical signal via a transmission line and what transmits a wireless signal can be used. Further, the notification unit 42 has a known writable storage means such as a RAM, and once holds power consumption and outputs it at an appropriate timing (for example, in response to an external request). Also good. In any case, since the notification unit 42 can be realized by a well-known technique, detailed illustration and description thereof are omitted.

  Here, FIG. 2 shows the relationship between the voltage across the detection capacitor C1 (hereinafter referred to as “detection voltage”) V1 and the measured power consumption Win. A black mark indicates a case where the amplitude (hereinafter simply referred to as “input voltage”) Vin of the input voltage to the diode bridge DB is 100V, and a white mark indicates a case where the input voltage Vin is 200V. As can be seen from FIG. 2, the relationship between the detection voltage V1 and the power consumption Win is substantially the same linear shape even when the input voltage Vin is different.

  This embodiment pays attention to the above points, and the calculation unit 41 calculates the power consumption Win by the expression Win = α × V1 + β using the detection voltage V1 and the constants α and β. Here, the constant β indicates power consumed by a circuit (not shown) that uses the DC power supply unit 1 as a power supply (for example, a circuit that generates power for the arithmetic unit 41 and the control unit 20). The output voltage Vdc is approximately the number Vdc / (η × R1) obtained by dividing the circuit efficiency η of the DC power supply unit 1 by the product of the resistance value R1 of the first resistor R1. It is desirable to determine by actual measurement. Since such a calculation unit 41 can be realized by a known electronic circuit, detailed illustration and description thereof will be omitted.

  According to the above configuration, the electric power input from the external AC power source AC is once converted into DC power of the predetermined voltage Vdc by the DC power source unit 1, so that the detection voltage V1 obtained from the subsequent stage of the DC power source unit 1 is external. Since it is difficult to receive a difference in power input from the AC power supply AC, an error due to a difference in power input from the outside hardly occurs in power consumption obtained by calculation using the detection voltage V1. Further, it is difficult to increase the size as compared with the case where a current transformer is used.

  Instead of making constants α and β used for calculation of power consumption Win constant, as shown in FIG. 3, for example, a memory comprising a ROM and storing a plurality of sets of constants α and β corresponding to a plurality of situations. If the unit 43 is provided, and the calculation unit 41 reads constants α and β corresponding to the situation from the storage unit 43 and uses them in the calculation of the power consumption Win, a more accurate power consumption Win can be obtained.

  In the example of FIG. 3, an input voltage determination unit 32 that determines which of the three voltages of 100 V, 200 V, and 242 V is provided based on the output voltage of the diode bridge DB is provided. The unit 43 stores three sets of constants α and β associated with the three input voltages Vin determined by the input voltage determination unit 32 in a one-to-one manner. The constants α and β corresponding to the determination result by 32 are read from the storage unit 43 and used for calculating the power consumption Win. According to this configuration, it is possible to further reduce the error of the power consumption Win due to the difference in the input voltage Vin. In this case, since the input voltage Vin does not change during the period in which the power supply is on, the calculation unit 41 refers to the determination result of the input voltage determination unit 32 only immediately after the power supply is turned on. And reading the constants α and β from the storage unit 43.

  As conditions for making the constants α and β different, in addition to the input voltage Vin as in the example of FIG. Specifically, constants α and β that are different for the preheating operation, the starting operation, and the steady operation are used. In general, the power supply device may perform a warm-up operation that makes the output different from the normal steady-state operation. In such a case, constants α and β that are different from those during the normal operation are also set during the warm-up operation. You may make it use.

  Alternatively, different constants α and β may be used depending on the ratio of the target value of the output power to the discharge lamp FL with respect to the rated power of the discharge lamp FL (hereinafter referred to as “dimming ratio”). Specifically, for example, the first set of constants α and β is used at a dimming ratio of 100% to 90%, and the second set of constants α and β is used at a dimming ratio of 90% to 80%. Different constants α and β are used for each light ratio of 10%.

  Further, since the relationship between the detection voltage V1 and the actual power consumption varies depending on the ambient temperature, a temperature detection unit 33 for detecting the temperature is provided as shown in FIG. 4, and temperature detection is performed from among a plurality of constants α and β. Constants α and β selected according to the temperature detected by the unit 33 may be used. As the temperature detection unit 44, for example, a thermistor can be mounted on a printed wiring board (not shown) on which the DC power supply unit 1 and the power conversion unit 2 are mounted. Alternatively, the temperature detection unit 44 may be connected to a network and acquire temperature data from an external device via the network.

  Further, as a method of changing the light output of the discharge lamp FL in accordance with the input to the instruction input unit 31, a method of changing the frequency and on-duty of turning on / off the switching elements Q1 and Q2 of the switching unit 21 as described above. In addition, there is a method of changing the output voltage Vdc of the DC power supply unit 1. In any case, the control according to the input to the instruction input unit 31 is performed according to the input to the instruction input unit 31 and the parameter to be changed according to the input (for example, the target value of the output voltage of the DC-DC converter 10). The data table indicating the relationship with () may be realized by using a data table stored in advance in a storage means such as a well-known ROM, for example, or by calculation. Even when the output voltage Vdc of the DC power supply unit 1 is changed as described above, it is selected according to the light output (dimming ratio) from among a plurality of α and β stored in the storage unit 43. By adopting the above-described configuration in which the arithmetic unit 41 uses the appropriate constants α and β for calculating the power consumption Win, an error in the power consumption Win due to the change in the output voltage Vdc of the DC power supply unit 1 can be suppressed.

(Embodiment 2)
In the present embodiment, as shown in FIG. 5, the power conversion unit 2 is not a half-bridge type inverter circuit, but a series circuit of a primary winding of the transformer T1 and a switching element Q3 that is on / off controlled by the control unit 20. , A known flyback converter including a series circuit of a diode and a capacitor connected between both ends of the secondary winding of the transformer T1, and a direct current for lighting the light emitting diode LED using the output power of the flyback converter. It is comprised with the lighting part 23 converted into electric power. Such appropriate changes to the load and the power conversion unit 2 are possible in other embodiments.

  In the present embodiment, the first resistor R1 connected in series to the switching element Q3 of the power converter 2 and one end connected to the connection point of the switching element Q3 and the first resistor R1 via the second resistor R2. A current detection unit including a detection capacitor C1 having the other end connected to the ground, an instruction input unit 31 that receives an input for instructing the light output of the light-emitting diode LED, and an instruction input to the instruction input unit 31 A control unit 20 that periodically drives the switching element Q3 on and off with an on-duty such that power corresponding to the light-emitting diode LED is supplied, and a calculation unit 41 that calculates power consumption based on the voltage across the detection capacitor C1. And a notification unit 42 that notifies the power consumption calculated by the calculation unit 41 to the outside, and a plurality of constants α and β used for the calculation of the calculation unit 41 are stored. The storage unit 43 is provided in the same manner as in the first embodiment. A description of parts common to the first embodiment will be omitted.

  Furthermore, unlike the first embodiment, the present embodiment does not include the DC power supply unit 1 that outputs DC power of a predetermined voltage, and the output voltage Vdc varies as an external power supply, not the AC power supply AC. A DC power source E such as a possible battery is used.

  In this embodiment, a power supply voltage detection unit (not shown) for detecting the input voltage Vdc from the DC power supply E is provided, and the storage unit 43 has a stage (range) of the input voltage Vdc from the DC power supply E. The constants α and β for each are stored, and the calculation unit 41 reads the constants α and β corresponding to the input voltage Vdc detected by the power supply voltage detection unit from the storage unit 43 and uses them for calculation of the power consumption Win. Since the power supply voltage detection unit and calculation unit 41 as described above can be realized by a well-known technique, a detailed description thereof will be omitted.

  According to the above configuration, it is possible to suppress an error in the power consumption Win due to the difference in the input power Vdc from the external DC power supply E. Further, it is difficult to increase the size as compared with the case where a current transformer is used.

(Embodiment 3)
Since the basic configuration of the present embodiment is common to the example of FIG. 1 of the first embodiment, the description of the common parts is omitted.

  In the present embodiment, as shown in FIG. 6, the A / D converter 44 that A / D converts the detection voltage V1 and the output of the A / D converter 44 are obtained a plurality of times for each predetermined measurement period. A cumulative addition unit 45 that periodically repeats the operation of outputting the total value of the output (hereinafter referred to as “cumulative voltage Vs”) to the calculation unit 41. In FIG. 6, the control unit 20 and the instruction input unit 31 are not shown.

  Furthermore, in the present embodiment, an output (hereinafter referred to as “periodic signal”) is generated such that the voltage value periodically changes over both positive and negative sides and the average value of the voltage value in one cycle becomes zero. The periodic signal generator 46 that outputs to the detection capacitor C1 via the third resistor R3 is provided. That is, the detection voltage V <b> 1 in the present embodiment is a voltage in which a voltage corresponding to a periodic signal is superimposed on a voltage corresponding to a current flowing through the switching unit 21. The periodic signal is, for example, a sine wave.

  Then, the cumulative addition unit 45 selects the total of the contribution of the periodic signal to the input voltage (that is, the detection voltage) V1 to the A / D conversion unit 44 over the entire measurement period for every predetermined measurement period. The output of the A / D conversion unit 44 is obtained at each of the plurality of timings (hereinafter referred to as “measurement timing”), and the value obtained by summing the obtained outputs of the A / D conversion unit 44 is calculated. Output to. For example, the measurement timing is as shown by t1 to t8 and t10 to t13 in FIG. In the example of FIG. 7, the voltage obtained by removing the contribution of the periodic signal from the detection voltage V1 is constant as shown by the broken line in the upper graph of FIG. 7, the periodic signal is a sine wave, and the measurement period is 1 of the periodic signal. The measurement period is started at the timing indicated by t1 and t10 in FIG. 7, and there are eight measurement timings in each measurement period. The intervals between the measurement timings t1 to t8 and t10 to t13 are as follows. They are equally spaced (1/8 times the period T of the periodic signal).

  Further, the cumulative voltage Vs is newly calculated for each measurement period, and the cumulative adder 45 calculates the cumulative voltage Vs after all the measurement timings t1 to t8 of one measurement period have been completed as shown in the lower part of FIG. After being output to the unit 41, the stored total value is returned to 0 at an appropriate timing t9 until t10 when the next measurement period starts.

  The calculation unit 41 calculates the power consumption Win by the equation Win = α × Vs + β using the cumulative voltage Vs output from the cumulative addition unit 45 and constants α and β every measurement period. That is, the total number of measurement timings in one measurement period (hereinafter referred to as “measurement count”) is set to n, and the output of the i-th A / D conversion unit 44 in n times is D (i). Then, the finally obtained power consumption Win is expressed as the following equation.

  Here, the A / D conversion unit 44 performs A / D conversion of the detection voltage V1 in units of a predetermined voltage (hereinafter referred to as “unit voltage”) k, and the detection voltage V1 is the unit voltage k. Assume that the output of the A / D converter 44 is an integer D when V1≈k × D using the integer D. That is, when the voltage value width that V1 can take is 5V, and this is expressed by the 10-bit integer D by the A / D converter 44, k = 5/1024 (V). The constant α in this embodiment is the constant α in Embodiment 1, that is, the output voltage Vdc of the DC power supply unit 1 is divided by the product of the circuit efficiency η of the DC power supply unit 1 and the resistance value R1 of the first resistor R1. It is about a number k × Vdc / (n × η × R1) obtained by multiplying a numerical value of about the number Vdc / (η × R1) by a number (k / n) obtained by dividing the unit voltage k by the number n of measurements. In addition, the constant β is the power consumed by a circuit (not shown) that uses the DC power supply unit 1 as a power supply (for example, a circuit that generates the power supply for the calculation unit 41 and the control unit 20), similarly to the constant β in the first embodiment. Indicates. However, like the constants α and β in the first embodiment, it is desirable to determine the constants α and β in the present embodiment by actual measurement.

  Further, consider a case where the output is an integer D when the detection voltage V1 is in the range of k × (D−0.5) ≦ V1 <k × (D + 0.5) for the integer D. In this case, if the detection voltage V1 is slightly smaller than k × (D−0.5), the output of the A / D converter 44 is D−1, and the detection voltage V1 is k × (D + 0.5) or more. If it is slightly larger, the output of the A / D converter 44 is D + 1. That is, with the A / D conversion described above, a maximum k × 0.5 quantization error occurs.

  When the periodic signal is not superimposed on the detection voltage V1, it is conceivable that the detection voltage V1 continues and becomes a voltage Vo slightly lower than the center k × D of the above range as shown in the upper part of FIG. In such a case, as shown in the middle part of FIG. 8, the output (AD value) of the A / D converter 44 continues to be D, and positive quantization errors continue to occur, so that the A / D converter 44 The above quantization error is accumulated in a value obtained by summing the output for a plurality of times. Thereby, as shown in the lower part of FIG. 8, the total of D (i) is 8D at the end of the measurement period t9. On the other hand, as shown in the upper part of FIG. 7, the detection voltage V <b> 1 that was originally a constant value Vo slightly lower than k × D, as indicated by the broken line, is superimposed on the output of the periodic signal generation unit 46 by a solid line. As shown in FIG. 7, the number of times corresponding to the degree to which the original detected voltage V1 (broken line in FIG. 7) falls below the center k × D of the above range is shown (3 in the figure). The output (AD value) of the A / D conversion unit 44 becomes D−1, and the total of D (i) at the end of the measurement period t9 (that is, the output of the cumulative addition unit 45) as shown in the lower part of FIG. Is 8D-3. As described above, when the original detection voltage V1 is shifted to the negative side with respect to the voltage k × D after A / D conversion and a positive quantization error occurs, the output of the A / D conversion unit 44 is output. Is likely to be D-1. On the contrary, when the original detection voltage V1 is shifted to the positive side with respect to the voltage k × D after A / D conversion and a negative quantization error occurs, the output of the A / D conversion unit 44 is The probability of becoming D + 1 increases. That is, in the output of the cumulative adder 45 that is the result of summing the output of the A / D converter 44 a plurality of times, the above-described quantization error is offset to some extent, so that the resolution of the A / D converter 44 is improved. As with, improvement in measurement accuracy can be expected. The more values that can be taken by the contribution of the periodic signal in the detection voltage V1 at the measurement timing, the more the relationship between the expected value of the output of the A / D converter 44 and the original detection voltage V1 (ie, switching). The above-described effect is enhanced when the relationship between the current flowing through the element Q2 and the current value approaches a straight line.

  The measurement timing at which the cumulative addition unit 45 obtains the output of the A / D conversion unit 44 is such that the periodic signal with respect to the detection voltage V1 at the measurement timing is measured for each measurement period in order to avoid occurrence of systematic errors due to the contribution of the periodic signal. It is only necessary that the total contribution is selected to be zero. If the waveform of the periodic signal is a sine wave, the above condition can be achieved relatively easily if the length of the measurement period is set to a natural number multiple of the period of the periodic signal and the measurement timings are equally spaced. It becomes.

  Here, although the effect can be obtained even if the amplitude (maximum absolute value) of the voltage superimposed by the periodic signal exceeds half k / 2 of the unit voltage, the effect is obtained, but it should be less than half k / 2 of the unit voltage. Is desirable.

  Note that the length of one cycle of the periodic signal is T, p is a natural number of 2 or more, q is a natural number, the length of the measurement period is (p + 1 / q) T, and the number of measurements is p × q. In this case, the relationship between the measurement timing and the phase of the periodic signal is made different for each period of the periodic signal within the measurement period, and the i-th measurement timing is set as the integer m = (i−1) / q (rounded down) to the measurement period. If (T / q) × (i−1) + m × T / (p × q) has elapsed from the start of the measurement, the phase of the periodic signal is maintained while the actual interval between measurement timings is equal to or greater than T / q. As a whole, the interval between measurement timings is the same as T / (p × q). Therefore, compared to the case where the interval of the measurement timing is always constant as in the example of FIG. 7, the value that can be taken by the contribution of the periodic signal in the detection voltage V1 at the measurement timing varies, so the A / D converter The relationship between the expected value of the output 44 and the current flowing through the switching element Q2 becomes closer to a straight line, that is, the quantization error is further suppressed.

  For example, when p = 3 and q = 8, the number of measurements is p × q = 3 × 8 = 24 times, and the interval between measurement timings is usually 1/8 of the periodic signal as shown in FIG. It becomes a period T / 8, and is between the last measurement timing t8 of the first period and the first measurement timing t9 of the second period, and the last measurement timing t16 of the second period and the first measurement timing of the third period. Between t17, each is longer than the normal interval T / 8 by T / (p × q) = T / 24, which is T / 6 corresponding to 1/6 period of the periodic signal. The measurement timing ti in the first period when 1 ≦ i ≦ 8 and the integer m is 0 is the time when (T / 8) × (i−1) has elapsed from the start of the measurement period, and 9 ≦ i ≦ 16 and the measurement timing ti in the second period when the integer m is 1 is the time when (T / 8) × (i−1) + (T / 24) has elapsed since the start of the measurement period, and 17 ≦ The measurement timing ti in the third period when i ≦ 24 and the above-mentioned integer m is 2 is the time when (T / 8) × (i−1) + (2 × T / 24) has elapsed since the start of the measurement period. Become. Accordingly, when the relationship between the measurement timing ti and the phase of the periodic signal is taken as a whole, it is the same as taking the measurement timing ti every 1/24 period (T / 24) of the periodic signal.

  Here, when q = 1, one measurement timing is provided for each period of the periodic signal, but one measurement timing may be provided for a plurality of periods of the periodic signal. In this case, if the time obtained by multiplying the actual length of one period signal by the number of period signals per measurement timing is regarded as one period, one measurement timing is set for each period signal period. Can be thought of as the same. In either case, the relationship between the measurement timing and the phase of the periodic signal is the same as when the measurement timing interval is shortened.

  Further, the periodic signal is not limited to a sine wave, and a so-called sawtooth waveform in which the voltage value is gradually increased linearly and then suddenly decreased as shown in the upper part of FIG. 10 is periodically repeated. Good. Since the periodic signal generator 46 that realizes such a periodic signal can also be realized by the periodic technique, detailed illustration and description thereof will be omitted. In the example of FIG. 10, in a state where the periodic signal is not superimposed, the detection voltage V1, which is a constant value Vo that is slightly lower than k × D, is superimposed on the periodic signal as indicated by a broken line in the upper part of FIG. Thus, the sawtooth waveform shown by the solid line is obtained. As a result, as shown in the middle stage of FIG. 10, the A / D conversion is performed by the number of times (four times in the figure) corresponding to the extent that the constant value Vo, which is the original detection voltage V1, falls below the center k × D of the range. The output (AD value) of the unit 44 becomes D-1, and the total of D (i) at the end of the measurement period t9 (that is, the cumulative voltage Vs output by the cumulative addition unit 45) is 8D− as shown in the lower part of FIG. 4 and the quantization error is suppressed.

  In the present embodiment, as in the first embodiment, it is possible to adopt a configuration in which the constants α and β used for calculating the power consumption Win are changed according to the situation. Further, the configuration using the cumulative voltage Vs for the calculation of the power consumption Win as in the present embodiment is also applicable to the configuration in which the DC power supply unit 1 is not provided as in the second embodiment.

(Embodiment 4)
Since the basic configuration of this embodiment is the same as that of the third embodiment, the description of the common parts is omitted.

  The output voltage Vdc of the DC-DC converter 10 comprising a switching power supply that converts pulsating power obtained by full-wave rectifying the AC power of the AC power supply AC by the diode bridge DB into DC power includes a ripple component of the output frequency of the diode bridge DB. That is, a ripple component having a frequency twice the frequency of the AC power is included, and a ripple component is also generated in the detection voltage V1 due to the ripple component. In this embodiment, paying attention to this point, the above-described ripple component in the detection voltage V1 is used as a periodic signal, thereby omitting the periodic signal generator 46 and the third resistor R3 as shown in FIG. .

  More specifically, for each measurement period, the measurement timing at which the cumulative addition unit 45 obtains the output of the A / D conversion unit 44 is such that the total contribution of the ripple components in the detection voltage V1 is zero. Is selected. If the length of the measurement period is an integer multiple of 50 ms, the length of the measurement period is an integral multiple of the period of the ripple component, regardless of whether the frequency of the AC power of the AC power supply AC is 50 Hz or 60 Hz. It can be.

  According to the above configuration, an error due to the ripple component of the output of the DC-DC converter 10 being reflected as the ripple component of the detection voltage V <b> 1 and a quantization error due to A / D conversion in the A / D conversion unit 44. , They can be suppressed by canceling each other.

  The amplitude of the ripple component changes according to the feedback gain in the feedback control of the DC-DC converter 10 and the capacitance value of the output capacitor C10.

  Among the various power supply devices described in the first to fourth embodiments, the power supply device PS including the communication unit 42a serving as a notification unit that transmits the power consumption Win calculated by the calculation unit 41 to the external device as illustrated in FIG. The power consumption measurement system can be configured together with the display device DP that displays the power consumption transmitted from the communication unit 42a of the power supply device PS.

  When specifically explaining the example of FIG. 12, the display device DP is connected to the communication unit 42a of each power supply device PS via the transmission line SL, and the power consumption transmitted from the communication unit 42a of each power supply device PS, respectively. The communication unit 51 to receive, the display unit 52 to display power consumption, the control unit 53 to control the display unit 52 to display the power consumption received to the communication unit 51, and the consumption received to the communication unit 51 And a storage unit 54 used as appropriate for storing data such as electric power.

  Here, the power consumption Win obtained as a result of calculation in the calculation unit 41 of the power supply apparatus PS and the power consumption transmitted / received via the transmission line SL are digital data expressed in binary numbers, respectively. The number of bits used for these expressions is not necessarily equal to each other, and the number of bits used for expressing the power consumption transmitted and received via the transmission line SL is used as the expression for the power consumption Win of the calculation result in the calculation unit 41. It may be less than the number of bits used. Specifically, for example, a predetermined number of lower bits of the power consumption Win of the calculation result in the calculation unit 41 are rounded down, and this is used as a representation of power consumption transmitted / received via the transmission line SL. If the power consumption resolution (unit power in the claims) transmitted / received via the transmission line SL is 5 mW, that is, when the power consumption is expressed as an integer multiple of 5 mW, the maximum of about 327 W in 2 bytes (16 bits). The power consumption of the width can be expressed, which is practically sufficient as the resolution and the width of the power consumption that can be expressed. By adopting this configuration, the communication load and the processing load on the display device DP are reduced as compared with the case where the power consumption Win obtained as a result of the calculation is directly transmitted and received in the calculation unit 41 of the power supply apparatus PS.

DESCRIPTION OF SYMBOLS 1 DC power supply part 2 Power conversion part 10 DC-DC converter 31 Instruction input part 32 Input voltage discrimination | determination part (input discrimination | determination part in a claim)
33 Temperature Detection Unit 41 Calculation Unit 42 Notification Unit 42a Communication Unit 43 Storage Unit 44 A / D Conversion Unit 45 Cumulative Addition Unit 46 Periodic Signal Generation Unit 51 Communication Unit 52 Display Unit AC AC Power Supply C1 Detection Capacitor (Current Detection in Claims) Part, analog current detection part)
DB Diode bridge DP Display device E DC power supply FL Discharge lamp (Load in claims)
LED light emitting diode (load in claims)
PS power supply device Q2, Q3 switching element R1 first resistor (current detection unit, analog current detection unit in claims)
R2 second resistance (current detection unit, analog current detection unit in claims)

Claims (15)

A DC power supply unit that converts electric power input from an external power source into DC power of a predetermined voltage and outputs it;
A power conversion unit including at least one switching element, appropriately converting DC power input from the DC power supply unit and supplying the converted power to a load;
A current detection unit that generates an output indicating a higher value as the current flowing through the switching element of the power conversion unit increases;
A calculation unit that calculates the power consumption Win by the expression Win = α × Vs + β using the output value Vs of the current detection unit and constants α and β,
A power supply device comprising: a notification unit that notifies the power consumption Win calculated by the calculation unit to the outside. A power conversion unit including at least one switching element, appropriately converting DC power input from an external DC power supply and supplying the converted power to a load;
A current detection unit that generates an output indicating a higher value as the current flowing through the switching element of the power conversion unit increases;
A power supply voltage detection unit for detecting an input voltage from an external DC power supply to the power conversion unit;
A plurality of types of constants α and β used for the calculation of the power consumption Win, each having a storage unit stored in association with the range of the input voltage detected by the power supply voltage detection unit,
Using the output value Vs of the current detection unit and the constants α and β read from the storage unit according to the input voltage detected by the power supply voltage detection unit, the power consumption Win is expressed by the equation Win = α × Vs + β. A computing unit for computing,
A power supply device comprising: a notification unit that notifies the power consumption Win calculated by the calculation unit to the outside. The DC power supply unit is one in which any of a plurality of types of power is alternatively input,
An input discriminating unit for discriminating the type of power input to the DC power source unit;
A plurality of types of constants α and β used for calculating power consumption Win, each of which includes a storage unit stored in association with the type of power determined by the input determination unit;
2. The power supply according to claim 1, wherein when calculating the power consumption Win, the calculation unit reads constants α and β corresponding to the type of power determined by the input determination unit from the storage unit and uses them in the calculation. apparatus. An instruction input unit for inputting an instruction of output power is provided,
The power conversion unit increases or decreases the output power according to the instruction input to the instruction input unit,
A plurality of types of constants α and β used for calculating power consumption Win are provided, each having a storage unit stored in association with the range of output power of the power conversion unit,
The power supply device according to claim 1, wherein when calculating the power consumption Win, the calculation unit reads constants α and β corresponding to the output power of the power conversion unit from the storage unit and uses them in the calculation. Each of the power conversion units can execute a plurality of types of operations having different relationships between the output value Vs of the current detection unit and the power consumption Win,
A plurality of types of constants α and β used for calculating the power consumption Win are provided, each of which includes a storage unit stored in association with the type of operation of the power conversion unit,
2. The power supply device according to claim 1, wherein when calculating the power consumption Win, the calculation unit reads constants α and β corresponding to the type of operation performed by the power conversion unit from the storage unit and uses them in the calculation. . A temperature detector for detecting the temperature;
A plurality of types of constants α and β used for calculating the power consumption Win, each having a storage unit stored in association with a temperature range detected by the temperature detection unit;
2. The power supply device according to claim 1, wherein when calculating the power consumption Win, the calculation unit reads constants α and β corresponding to the temperature detected by the temperature detection unit from the storage unit and uses them in the calculation. The current detector is
An analog current detector that outputs a higher analog voltage as the current flowing through the switching element of the power converter increases,
A periodic signal generating unit that generates a periodic signal that is an analog voltage whose voltage value periodically changes across both positive and negative sides;
An A / D converter for A / D converting and outputting a voltage in which a periodic signal is superimposed on an output voltage of the analog current detector;
Each A / D converter at a plurality of measurement timings selected so that the total of the contribution of the output voltage of the periodic signal generator to the input voltage to the A / D converter is 0 for each predetermined measurement period. And an accumulative addition unit that uses a value obtained by summing the obtained output values of the A / D conversion unit as a value Vs of an output to the calculation unit. The power supply device according to any one of the above.   8. The power supply device according to claim 7, wherein the measurement period extends over a plurality of periods of the periodic signal, and the relationship between the phase of the periodic signal and the measurement timing is shifted for each period of the periodic signal. Using the length T of one period of the periodic signal, the natural number p of 2 or more, and the natural number q, the length of the measurement period is expressed as (p + 1 / q) T, and the measurement timing during one measurement period Is expressed as p × q,
For each i satisfying 1 ≦ i ≦ p × q, the time from the start of the measurement period to the i-th measurement timing is calculated using the integer m = (i−1) / q (rounded down) (T The power supply device according to claim 8, wherein the power supply device is represented by: / q) × (i−1) + m × T / (p × q). A DC power supply unit that converts electric power input from an external power source into DC power of a predetermined voltage and outputs it;
A power conversion unit including at least one switching element, appropriately converting DC power input from the DC power supply unit and supplying the converted power to a load;
An analog current detector that outputs a higher analog voltage as the current flowing through the switching element of the power converter increases,
A periodic signal generating unit that generates a periodic signal that is an analog voltage whose voltage value periodically changes across both positive and negative sides;
An A / D converter for A / D converting and outputting a voltage in which a periodic signal is superimposed on an output voltage of the analog current detector;
Every n (n ≧ 2) measurement timings selected so that the total contribution of the output voltage of the periodic signal generation unit to the input voltage to the A / D conversion unit becomes 0 for each predetermined measurement period. The output D (i) of the A / D converter is obtained, and the following equation is used by using the sum of the outputs D (i) obtained over the entire measurement period and the constants α and β.

A cumulative calculation unit for calculating the power consumption Win by
A power supply device comprising: a notification unit that notifies the power consumption Win calculated by the calculation unit to the outside.   The power supply apparatus according to any one of claims 1 to 10, wherein the DC power supply unit converts input AC power into DC power. The DC power supply unit includes a diode bridge that performs full-wave rectification of AC power input from an external AC power supply, a DC-DC converter that includes a switching power supply, converts the output power of the diode bridge to DC power of a predetermined voltage, and outputs the DC power Consists of
The current detector is
An analog current detector that outputs a higher analog voltage as the current flowing through the switching element of the power converter increases,
An A / D converter for A / D converting and outputting a voltage in which a periodic signal is superimposed on an output voltage of the analog current detector;
Every n (n ≧ 2) measurement timings selected so that the total contribution of ripple components of the output of the DC-DC converter to the output voltage of the analog current detection unit becomes 0 for each predetermined measurement period. The output D (i) of the A / D conversion unit is obtained, and a cumulative addition unit that uses a value obtained by summing the obtained output values of the A / D conversion unit as a value Vs of an output to the calculation unit. The power supply device according to claim 1, wherein the power supply device is any one of claims 1 to 6.   The power supply apparatus according to any one of claims 1 to 12, wherein a load connected to the power conversion unit is a light source. The power supply device according to any one of claims 1 to 13, further comprising a communication unit as a notification unit that transmits data indicating power consumption.
A power consumption measurement system comprising: a communication unit that receives power consumption transmitted from a power supply device; and a display device that displays a power consumption indicated in data received by the communication unit. The communication unit of the power supply device transmits, as data indicating the power consumption, the number obtained by dividing the power consumption calculated by the calculation unit by a predetermined unit power and rounded down.
15. The power consumption measuring system according to claim 14, wherein the display unit of the display device displays power consumption obtained by multiplying the number obtained from the data received by the communication unit by unit power.

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