JP7572204B2 - Reactor loss measuring device and waveform measuring device - Google Patents

Description

The present invention relates to a reactor loss measuring device and a waveform measuring device in a switching power supply device having a reactor for a filter.

In switching power supplies such as inverters, power factor correction circuits (hereinafter referred to as "PFC circuits"), and DC/DC converters that perform direct current/alternating current (DC/AC conversion) conversion using next-generation devices (semiconductor elements) such as SiC devices and GaN devices, device losses have been improved, but on the other hand, the proportion of losses in magnetic components such as AC reactors for filters has increased, making it essential to measure losses in magnetic components in order to further reduce losses. The measurement of the effective power, which is the loss, compared to the high-frequency apparent power of the reactors used in high-frequency inverters is a power measurement under low power factor conditions (e.g., 0.05 or less), and even a slight measurement circuit phase error has a significant impact on the measurement results.

Patent Document 1 discloses a calibration system that adjusts the results of power measurement in a power measurement device. Patent Document 2 discloses an iron loss measurement device for magnetic materials that quantitatively grasps the amount of error (absolute value error amount, phase error amount) during iron loss measurement, corrects the amount of error when calculating iron loss, and measures accurate iron loss measurements. Furthermore, Non-Patent Document 1 discloses a shunt resistor circuit that aims to reduce phase errors.

JP 2010-216997 A Japanese Patent Application Publication No. 1-285881

IEEJ Journal 1A, 8[4] (2019) p. 669-676

Figure 17 is a waveform diagram of high-frequency ringing caused by reactor stray capacitance to explain the conventional problem. The horizontal axis of the upper and lower waveform diagrams in Figure 17 is time (s), the vertical axis of the upper waveform diagram is reactor voltage, and the vertical axis of the lower waveform diagram is reactor current.

In Patent Document 1, a resistive load with a power factor of 1 is used to calibrate (adjust) the phase error of the measuring device, but because the resistive load contains inductance, errors in the phase calibration occur. In Patent Document 2, in order to measure accurate iron loss measurements, phase shift processing is performed on the measurement signal for iron loss calculation, but the amount of phase shift must be measured by a separate device. In Non-Patent Document 1, a special shunt resistor circuit is proposed to reduce phase errors, but this requires the insertion of a shunt resistor circuit into the actual equipment circuit, which affects circuit operation and may not be usable when the actual equipment is installed and operating.

In addition, as shown in Figure 17, high-frequency ringing (e.g., 10 MHz) occurs in the reactor voltage and reactor current during high-speed switching operations in a real machine environment due to the influence of the reactor stray capacitance (capacitor component), and as a result, it has been confirmed that even a small phase error can have a significant effect on the calculation results.

The reactor loss measurement device of the present invention is configured to measure a reactor voltage and a reactor current of a filter reactor provided on the output side or the input side of a switching circuit that performs power conversion by switching using a high-frequency drive signal to obtain a measurement signal on a time axis , calculate a phase error on the time axis of the measurement circuit using the measurement signal, perform a phase adjustment of the phase error, and calculate a reactor loss by power calculation of the reactor signal, and is characterized in that when signal phase shift processing is performed by shifting the phase of the reactor voltage or the reactor current within a predetermined range, and calculating the phase error on the time axis of the measurement circuit based on the relationship between the amount of phase shift on the time axis in the signal phase shift processing and a power value calculation result, a power amount change rate corresponding to each of the phase shift amounts is calculated using a plurality of the phase shift amounts on the time axis and the power value calculation result, and the phase shift amount on the time axis corresponding to the minimum value of the power amount change rate is calculated as the phase error. Another reactor loss measurement device of the present invention is configured to measure the reactor voltage and reactor current of a filter reactor provided on the output side or input side of a switching circuit that performs power conversion by switching using a high-frequency drive signal to obtain a measurement signal, calculate a phase error of the measurement circuit using the measurement signal, perform phase adjustment of the phase error, and calculate the reactor loss by power calculation of the reactor signal. The phase of the reactor voltage or the reactor current is shifted within a predetermined range to perform signal phase shift processing, and when calculating the phase error of the measurement circuit based on the relationship between the phase shift amount and the power value calculation result in the signal phase shift processing, a power amount change rate corresponding to each of the phase shift amounts is calculated using a plurality of the phase shift amounts and the power value calculation result, and the phase shift amount corresponding to the minimum value of the power amount change rate is calculated by using the calculated phase error value as the center, and a second-order polynomial approximation function P(t) of the power amount change rate is calculated by the following formula using the values of the plurality of phase shift amounts and the power amount change rate, and the phase error is calculated as -p2/p1/2. The quadratic polynomial approximation function P(t) of the following formula is found, and the phase error is converted into time as tmin = -p2/p1/2: P(t) = p1 * t^2 + p2 * t + p3 , where t is the time converted value t (ns) of the phase shift, and p1, p2, and p3 are coefficients of the quadratic polynomial approximation function P(t).

The waveform measuring device of the present invention is characterized by having the functions of the reactor loss measuring device.

According to the present invention, the phase error calibration of the measurement circuit and reactor loss calculation are performed using the measurement signals of the reactor voltage and reactor current, so that a reactor loss measurement device can be provided that can measure reactor loss with high accuracy without being affected by the phase error of the measurement circuit, and a dedicated excitation power supply circuit or phase error measurement device is not required, and measurements can be made while the actual device is operating. Therefore, it can be applied to reactor loss measurement of three-phase inverters, single-phase inverters, DC/DC converters, PFC circuits, etc. Specifically, it has the following effects.

(a) Phase error calibration can be performed by utilizing magnetic hysteresis characteristics and reactor stray capacitance characteristics.
(b) Automatic calibration is performed based on the reactor voltage and reactor current being measured, resulting in high accuracy and simple operation.
(c) Measurements can be performed while the device is installed on the actual equipment.

FIG. 1 is a circuit diagram showing a configuration example of a switching power supply device (e.g., a three-phase inverter) according to a first embodiment of the present invention. FIG. 2 is a circuit diagram showing a configuration example of an iron loss power calculation unit 45 in FIG. FIG. 2 is a circuit diagram showing a configuration example of an iron loss power calculation unit 46 in FIG. Functional block diagram of a phase error calibration power calculation device A flowchart showing the iron loss phase characteristic calculation process in FIG. A flowchart showing the phase error calibration calculation process in FIG. Waveform diagram showing an example of iron loss phase characteristic calculation results when high-frequency ringing due to stray capacitance does not occur FIG. 18 is a waveform diagram showing an example of the iron loss phase characteristic calculation result when the high-frequency ringing shown in FIG. 17 occurs. 5 is a flowchart showing the overall phase error calibration process of FIG. A flowchart showing the reactor loss calculation process including FIG. FIG. 1 is a circuit diagram showing a configuration example of a switching power supply device (e.g., a three-phase inverter) according to a second embodiment of the present invention. Functional block diagram of a phase error calibration power calculation device Input filter diagram Circuit diagram showing an example of a single-phase inverter configuration A circuit diagram showing a configuration example of a three-phase PFC circuit. Circuit diagram showing a configuration example of a single-phase PFC circuit High-frequency ringing waveform caused by reactor stray capacitance

The mode for carrying out the present invention will become clear from the following description of the preferred embodiment when read in conjunction with the accompanying drawings. However, the drawings are for illustrative purposes only and are not intended to limit the scope of the present invention.

(Configuration of the First Embodiment)
1(a) and (b) are circuit diagrams showing an example of the configuration of a switching power supply device (e.g., a three-phase inverter) in a first embodiment of the present invention, where (a) is an overall diagram of the three-phase inverter, and (b) is a diagram of a reactor loss measuring device in (a).
1(a), a three-phase inverter 2 that performs three-phase DC/AC conversion is connected to a DC power source 1, and three-phase AC power output from the three-phase inverter 2 is supplied to a load 3. Note that a system power supply may be connected to the output side of the three-phase inverter 2 instead of the load 3.

The three-phase inverter 2 has a switching circuit 10 that converts DC power supplied from a DC power source 1 into three-phase AC power, and a load 3 is connected to the output side of the switching circuit 10 via an output filter 20. The switching circuit 10 has a plurality of switches 11 to 16 that are turned on/off by high-frequency drive signals (e.g., a plurality of drive pulses) S1 to S6 supplied from a control unit (not shown), and these switches are bridge-connected. Each switch 11 to 16 is composed of a next-generation device such as a SiC device or a GaN device (e.g., a semiconductor element such as an insulated gate bipolar transistor (IGBT)). Feedback diodes 11a to 16a are connected in inverse parallel to each switch 11 to 16. The output filter 20 is composed of an LC filter consisting of three-phase reactors 21 to 23 and three-phase capacitors 24 to 26 branched and connected to the reactor 21. A secondary winding 27 for measurement is added to the reactor 21, and a reactor loss measurement device 30 is connected to the secondary winding 27. The reactor 21 and the secondary winding 27 have a predetermined voltage conversion ratio (for example, 1:1).

The reactor loss measuring device 30 is a device that measures the reactor iron loss of the reactor 21 through the secondary winding 27, and is composed of a waveform measuring device such as an oscilloscope having a calculation function. This reactor loss measuring device 30 has a voltage measuring device 31 that measures the reactor voltage vl applied to both ends of the reactor 21 through the secondary winding 27, and a current measuring device 32 that measures the reactor current il flowing through the reactor 21. The voltage measuring device 31 is composed of, for example, a voltage probe for an oscilloscope. The current measuring device 32 is composed of, for example, a current probe for an oscilloscope, a shunt resistance measuring circuit, etc. A measurement signal (e.g., a voltage measurement signal) S31 of the reactor voltage vl measured by the voltage measuring device 31 and a measurement signal (e.g., a current measurement signal) S32 of the reactor current il measured by the current measuring device 32 are provided to the measurement recording device 33. The measurement and recording device 33 is a device that records the input voltage measurement signal S31 and current measurement signal S32, and is composed of an oscilloscope or the like, and the output side is connected to the calculation device 34. The calculation device 34 is a device that calculates the reactor iron loss by calculation, and is composed of, for example, the calculation function in the oscilloscope, a personal computer, etc.

FIG. 1B shows a functional block diagram of a measurement device main body 40 that is composed of the measurement and recording device 33 and the calculation device 34 of FIG.
The measurement device main body 40 calculates the phase error of the measurement circuit composed of the voltage meter 31 and the current meter 32 using the voltage measurement signal S31 and the current measurement signal S32, performs phase adjustment (calibration), and measures the reactor iron losses S45, S46 by power calculation (=S41×S42) of the reactor voltage signal S41 and the reactor current signal S42. This measurement device main body 40 has a signal phase shift processing unit 41 that inputs the voltage measurement signal S31 measured by the voltage meter 31, a signal phase shift processing unit 42 that inputs the current measurement signal S32 measured by the current meter 32, and a switching frequency calculation unit 43.

The signal phase-shift processing unit 41 changes (shifts) the phase of the input voltage measurement signal S31 based on the phase-shift parameter ps1, performs processing to make it coincide with the phase of the current measurement signal S32, and outputs the reactor voltage signal S41. The signal phase-shift processing unit 42 changes (shifts) the phase of the input current measurement signal S32 based on the phase-shift parameter ps2, performs processing to make it coincide with the phase of the voltage measurement signal S31, and outputs the reactor current signal S42. The switching frequency calculation unit 43 performs fast Fourier transform (hereinafter referred to as "FFT") analysis of the input current measurement signal S32 to calculate the switching frequency fsw, and the switching period calculation unit 44 is connected to the output side. The switching period calculation unit 44 calculates the switching period Tsw from 1/fsw.

Two iron loss power calculation units 45, 46 are connected to each signal phase shift processing unit 41, 42. One iron loss power calculation unit 45 calculates the reactor iron loss S45 by power calculation (= S41 x S42) of the reactor voltage signal S41 and the reactor current signal S42 based on the AC period Tac, and the calculation result recording unit 47 is connected to the output side. The other iron loss power calculation unit 46 calculates the reactor high-frequency iron loss S46 by power calculation (= S41 x S42) of the reactor voltage signal S41 and the reactor current signal S42 based on the switching period Tsw, and the calculation result recording unit 47 is connected to the output side. The calculation result recording unit 47 is composed of a memory, a register, etc. that records the calculated reactor iron losses S45, S46.

但し、Ｔ；計算期間であって、交流周期Ｔａｃ又はその倍数。 FIG. 2 is a circuit diagram showing an example of the configuration of the iron loss power calculation unit 45 in FIG.
The iron loss power calculation unit 45 is composed of a multiplier 45a that multiplies the voltage signal V(t) which is the reactor voltage signal S41 by the current signal i(t) which is the reactor current signal S42, and an average calculation unit 45b connected to the output side of the multiplier 45a. The average calculation unit 45b is a circuit that receives the multiplication result of the multiplier 45a, calculates the average of a specified period T according to the following equation (1), and obtains a power value P which is the reactor iron loss S45.

where T is a calculation period, which is an AC period Tac or a multiple thereof.

但し、Ｔ；計算期間であって、スイッチング周期Ｔｓｗ又はその倍数。 FIG. 3 is a circuit diagram showing an example of the configuration of the iron loss power calculation unit 46 in FIG.
The iron loss power calculation unit 46 is composed of a multiplier 46a that multiplies the voltage signal V(t) which is the reactor voltage signal S41 by the current signal i(t) which is the reactor current signal S42, and an average calculation unit 46b connected to the output side of the multiplier 46a. The average calculation unit 46b is a circuit that receives the multiplication result of the multiplier 46a, calculates the average of a specified period T according to the following equation (2), and finds a power value P which is the reactor iron loss S46.

where T is a calculation period, which is a switching period Tsw or a multiple thereof.

(Operation of the Three-Phase Inverter of the First Embodiment)
In Fig. 1(a), a control unit (not shown) generates three-phase driving pulses S1 to S6 for constant voltage control, for example, by pulse width modulation (hereinafter referred to as "PWM"), and a plurality of switches 11 to 16 in a switching circuit 10 are alternately turned on and off. Then, a DC voltage supplied from a DC power source 1 is switched and converted into a three-phase AC voltage. The converted three-phase AC voltage has its harmonic components removed by reactors 21 to 23 and capacitors 24 to 26 in an output filter 20, and is supplied to a load 3. When the three-phase output voltage supplied to the load 3 fluctuates, the control unit changes the pulse width of the driving pulses S1 to S6 so as to suppress the fluctuation, and the three-phase output voltage is maintained at a target voltage.
In an actual circuit environment, a phase error calibration method and a reactor loss measurement method using the reactor loss measurement device 30 are performed as follows.

(Phase Error Calibration Method of the First Embodiment)
FIG. 4 is a functional block diagram of a phase error calibration power calculation device for performing a phase error calibration method using the measurement device main body 40 of FIG. 1(b).
The phase error calibration power calculation device 40A has a signal phase shift processing unit 41 that inputs a voltage measurement signal S31, and a signal phase shift processing unit 42 that inputs a current measurement signal S32. The signal phase shift processing unit 41 shifts the voltage measurement signal S31 based on a phase shift parameter ps1 supplied from the iron loss phase characteristic calculation unit 48 to synchronize the voltage measurement signal S31 with the current measurement signal S32 (i.e., shifts the phase of the voltage measurement signal S31 to match the phase of the current measurement signal S32) to obtain a reactor voltage signal S41, and the iron loss power calculation unit 45 is connected to the output side of the signal phase shift processing unit 41. The signal phase shift processing unit 42 shifts the current measurement signal S32 based on a phase shift parameter ps2 supplied from the iron loss phase characteristic calculation unit 48 to synchronize the current measurement signal S32 with the voltage measurement signal S31 to obtain a reactor current signal S42, and the iron loss power calculation unit 45 is connected to the output side of the signal phase shift processing unit 41. The iron loss phase characteristic calculation section 48 repeatedly calculates the iron loss by changing the phase, obtains two phase shift parameters ps1 and ps2, and provides them to the two signal phase shift processing sections 41 and 42, respectively.

The two signal phase shift processing units 41, 42 are equivalent to the deskew function used in power analyzers and the like, and shift the phase of either the voltage measurement signal S31 or the current measurement signal S32 in the lead or lag direction in order to synchronize the phases of the voltage measurement signal S31 and the current measurement signal S32. Also, the frequency is constant and the angle parameter can be converted to time, and there are cases where two switching frequency components exist due to the influence of the modulation method, so it may not be possible to express it as an angle. Therefore, in the phase shift processing of this embodiment 1, the phase error is converted into time units.

The iron loss power calculation unit 45 calculates the reactor iron loss S45 by multiplying the input reactor voltage signal S41 and reactor current signal S42 based on the AC period Tac, and the calculation result recording unit 47 and phase error calibration calculation unit 49 are connected to the output side. The calculation result recording unit 47 records the calculated reactor iron loss S45, etc., in order to record data necessary for the phase error calibration calculation in the subsequent stage. The phase error calibration calculation unit 49 performs a phase error calibration calculation using the recorded reactor iron loss S45, etc., and outputs the phase error calibration result S49.

FIG. 5 is a flowchart showing the iron loss phase characteristic calculation process in the iron loss phase characteristic calculation unit 48 in FIG.
In the iron loss phase characteristic calculation process in the iron loss phase characteristic calculation unit 48, the phase is changed (shifted) to repeatedly calculate the iron loss, and the phase shift parameters ps1, ps2 for performing the final iron loss calculation are obtained. In this iron loss phase characteristic calculation process, the voltage measurement signal S31 and the current measurement signal S32 are changed in a predetermined phase range (i.e., the phase (time converted value) is changed in the range of t1 to t2) at constant (change step ΔT) intervals, and the iron loss corresponding to each phase value is calculated.

For example, when the iron loss phase characteristic calculation process is started, in step ST1, the phase shift amount (Tshift) is set to an initial value (t1) (Tshift = t1). Here, the initial value (t1) is a negative value, and is the direction in which the current measurement signal S32 advances relative to the voltage measurement signal S31. After the initial value is set, in step ST2, a high-frequency iron loss calculation is performed, and in the next step ST3, the calculation result (i.e., the high-frequency iron loss calculation result for the phase shift amount) is recorded.

After recording, in step ST4, the phase shift amount (Tshift) is changed (Tshift = previous value of Tshift + ΔT, where ΔT is the change step), and the process proceeds to step ST5. In step ST5, it is determined whether the calculation of the change range of the phase shift amount (Tshift) is complete (Tshift > t2?), and if the calculation is incomplete (No), the process returns to step ST2, and if the calculation is complete (Yes), the iron loss phase characteristic calculation process ends.

FIG. 6 is a flowchart showing the phase error calibration calculation process in the phase error calibration calculation unit 49 in FIG.
7(a) and (b) are waveform diagrams showing an example of the iron loss phase characteristic calculation result when high frequency ringing due to stray capacitance does not occur, where (a) is a waveform diagram showing an example of the iron loss calculation value graphed as the processing result of the flowchart of FIG. 5, and (b) is a waveform diagram showing an example of the change rate calculation value graphed as the processing result of the flowchart of FIG. 6. The horizontal axis of FIG. 7(a) and (b) is the time equivalent value t (ns) of the phase shift (where positive: delays the current signal; negative: delays the voltage signal). The vertical axis of FIG. 7(a) is the iron loss calculation result (loss Ploss of power P), and the vertical axis of FIG. 7(b) is the calculation result change rate (loss ΔPloss of power change ΔP corresponding to unit time (1 ns, 5 ns, etc.)).

Figures 8(a) and (b) are waveform diagrams showing an example of the iron loss phase characteristic calculation result when the high frequency ringing shown in Figure 17 occurs, where (a) is a waveform diagram showing an example of the calculation result of the flowchart in Figure 5, and (b) is a waveform diagram showing an example of the calculation result of the flowchart in Figure 6. The horizontal axis of Figures 8(a) and (b) is the time equivalent value t (ns) of the phase shift. The vertical axis of Figure 8(a) is the iron loss calculation result (loss Ploss of power P), and the vertical axis of Figure 8(b) is the calculation result change rate (loss ΔPloss of power change ΔP corresponding to unit time (1 ns, 5 ns, etc.)).

As shown in Figure 6, in the phase error calibration calculation process in the phase error calibration calculation unit 49, the rate of change of each phase value is calculated from the results of the iron loss phase characteristic calculation process in Figure 5, and the phase value corresponding to the minimum value of the rate of change is set as the phase error of the measurement circuit. Furthermore, in order to calculate highly accurate and stable calibration results, a second-order polynomial approximation function of the data in the vicinity of the minimum value in Figures 7 and 8 (parts shown by thick lines) is found, and the phase error is calculated using the coefficients of the approximation function.

Figures 8(a) and (b) show examples of iron loss phase characteristic calculation results under conditions where ringing occurs. These figures (a) and (b) are waveform diagrams showing the reactor loss calculation results and their rate of change when the phase difference between the reactor voltage and reactor current is changed artificially. Ideally, the reactor loss changes in proportion to the phase difference, but the hysteresis characteristics of the magnetic components and the ringing operation due to stray capacitance affect the change characteristics of the calculation results. In this embodiment 1, this physical phenomenon is utilized to find the time (phase) corresponding to the low value of the thick line in the figure, thereby finding the phase error of the measurement circuit.

For example, when the phase error calibration calculation process in FIG. 6 is started, in step ST11, the rate of change of the calculation result per unit time is calculated using the following formula.
Rate of change (n) = (iron loss (n-1) - iron loss (n+1))/2
Here, n is the index number of the data. Then, in step ST12, the phase shift amount corresponding to the minimum value of the rate of change is set as the initial value of the phase error.
In the process (A) of steps ST11 and ST12, a power amount change rate corresponding to each phase shift amount is calculated using a plurality of phase shift amounts and the power value calculation results, and the phase shift amount corresponding to the minimum of the power amount change rates is set as the phase error.

Next, in step ST13, x is the phase shift amount, y is the rate of change per unit time, and using data within the phase shift amount range tmin-T to tmin+T, a quadratic polynomial approximation function of the rate of change for the phase shift amount is calculated as follows:
P(t)=p1*t^2+p2*t+p3
Then, in step ST14, the phase error is updated (tmin=-p2/p1/2).
In the process (B) of steps ST13 and ST14, the phase error is calculated by finding a second-order polynomial approximation function of the rate of change in power using a plurality of phase shift amounts and values of the rate of change in power, centered on the calculated phase error value.

In step ST15 after step ST14, it is determined whether the repeated calculation has been performed a predetermined number of times or more, and if it has not been performed the predetermined number of times (No), the process returns to step ST13, and if it has been performed the predetermined number of times or more (Yes), the process proceeds to step ST16. The repeated calculation in step ST15 can improve the calculation accuracy.
In the process (C) of step ST15, the calculation for obtaining the quadratic polynomial approximation function is repeated a predetermined number of times.
Thereafter, in step ST16, the phase error calibration result is determined (tmin), and then the phase error calibration calculation process is terminated.

Figures 8(a) and (b) show examples of iron loss phase characteristic calculation results under conditions where ringing occurs. The high-frequency power fluctuations in the calculation results are due to the resonance between the wiring inductance and the reactor stray capacitance, and the phase error of the measurement circuit can be calculated by determining the zero crossing of the power fluctuations. The rate of change corresponding to the zero crossing also becomes a minimum value, so the flowchart in Figure 6 can handle both cases.

FIG. 9 is a flowchart showing the entire phase error calibration process in the phase error calibration power calculation device 40A of FIG.
9, in step ST21, the reactor voltage vl and the reactor current il are measured by the voltage measuring device 31 and the current measuring device 32, and a voltage measurement signal S31 and a current measurement signal S32 are obtained. Note that measurements may be performed by another waveform measuring device, and the voltage measurement signal and the current measurement signal may be obtained by communication or data copy.

Next, in step ST22, the iron loss phase characteristic calculation process of FIG. 5 is performed, and in the next step ST23, the phase error calibration calculation process of FIG. 6 is performed. After that, in step ST24, the phase error calibration result S49 is output, recorded, and displayed, and the phase error calibration process is terminated.

(Method of Measuring Reactor Loss in Example 1)
FIG. 10 is a flowchart showing the reactor loss calculation process including the phase error calibration process of FIG.
In this reactor loss calculation process, in step ST21, the reactor voltage vl and the reactor current il are measured by the voltage measuring device 31 and the current measuring device 32, and a voltage measurement signal S31 and a current measurement signal S32 are obtained. Note that measurements may be performed by another waveform measuring device, and the voltage measurement signal and the current measurement signal may be obtained by communication or data copy.

Next, in step ST22, the iron loss phase characteristic calculation process of FIG. 5 is performed, and in the next step ST23, the phase error calibration calculation process of FIG. 6 is performed. Furthermore, in step ST25, the phase error calibration calculation result is set as the phase shift parameters ps1 and ps2 of FIG. 1(b), and the reactor loss calculation process is performed. After that, in step ST26, the reactor loss calculation result is output, recorded, and displayed, and the reactor loss calculation process is terminated.

(Effects of Example 1)
The reactor loss measurement in this embodiment 1 is a power measurement under low power factor conditions (for example, 0.05 or less), and a slight measurement circuit phase error has a large effect on the measurement result. In an ideal reactor operation, a power calculation error proportional to the phase error (Δφ) occurs, but due to the influence of the AC reactor magnetic hysteresis characteristics and the high-frequency ringing waveform, the calculation error characteristics shown in Figures 7(a), (b) and 8(a), (b) have been confirmed. The horizontal axis of Figures 7(a), (b) and 8(a), (b) is a time conversion value equivalent to the phase error, and when it is positive, the reactor current is delayed by the phase shift processing of the signal, and when it is negative, the reactor current is advanced by the phase shift processing (the reactor voltage may be delayed). Figures 7(a), (b) and 8(a), (b) respectively show the reactor loss calculation results and their change rates when the signal phase is changed. 7(a) and (b) show an example of the calculation result when there is no ringing waveform, and Fig. 8(a) and (b) show an example of the calculation result when there is a ringing waveform. When there is no phase error in the measurement circuit, the shift amount of the phase shift processing is zero and the rate of change is minimum. Conversely, the phase shift amount at which the rate of change is minimum can be regarded as the phase error of the measurement circuit.

In other words, Figures 7(a) and (b) and Figures 8(a) and (b) are waveform diagrams showing the reactor loss calculation results and their rate of change when the phase difference between the reactor voltage vl and reactor current il is changed artificially. Ideally, the reactor loss changes in proportion to the phase difference, but the hysteresis characteristics of the magnetic parts and the ringing action due to stray capacitance affect the change characteristics of the calculation results. This embodiment 1 utilizes such a physical phenomenon to find the time (phase) corresponding to the low value of the thick line in the figure, thereby finding the phase error of the measurement circuit.

As described above, according to the first embodiment, the measurement signals of the reactor voltage vl and the reactor current il are used to perform phase error calibration of the measurement circuit and reactor loss calculation, so that a reactor loss measurement device capable of measuring reactor iron loss with high accuracy can be provided, and a dedicated excitation power supply circuit or phase error measurement device is not required, and measurements can be made while the actual device is operating. Therefore, the present invention can be applied to reactor loss measurement of three-phase inverters, single-phase inverters, DC/DC converters, PFC circuits, etc. Specifically, the following effects are achieved.

(a) Phase error calibration can be performed by utilizing magnetic hysteresis characteristics and reactor stray capacitance characteristics.
(b) Automatic calibration is performed based on the reactor voltage vl and reactor current il of the measurement object, resulting in high accuracy and simple operation.
(c) Measurements can be performed while the device is installed on the actual equipment.

(Configuration of Example 2)
11(a) and (b) are circuit diagrams showing a configuration example of a switching power supply device (e.g., a three-phase inverter) in Example 2 of the present invention, where (a) is an overall diagram of the three-phase inverter, and (b) is a diagram of a reactor loss measuring device in (a). In Figs. 11(a) and (b), elements common to elements in Figs. 1(a) and (b) showing Example 1 are given the same reference numerals.

As shown in FIG. 11( a ), in a reactor loss measuring device 30A of the second embodiment, the secondary winding 27 for measurement provided in the reactor 21 of the first embodiment is omitted, and a voltage measuring device 31 is used to measure a reactor voltage vl directly from both ends of the reactor 21.
11(b), the configuration of a measurement device main body 40B constituting a reactor loss measurement device 30A of the present embodiment 2 is slightly different from the configuration of the measurement device main body 40 of embodiment 1. In the measurement device main body 40B of the present embodiment 2, two switching frequency high frequency component extraction units 51 and 52, a total power loss calculation unit 53, and a subtraction unit 54 are added to the measurement device main body 40 of embodiment 1.

One switching frequency high frequency component extraction unit 51 extracts switching frequency high frequency components from the reactor voltage signal S41 output from the signal phase shift processing unit 41 based on the switching period Tsw, and provides the switching component voltage signal S51 from which the high frequency components have been extracted to the two iron loss power calculation units 45, 46. The other switching frequency high frequency component extraction unit 52 extracts switching frequency high frequency components from the reactor current signal S42 output from the signal phase shift processing unit 42 based on the switching period Tsw, and provides the switching component current signal S52 from which the high frequency components have been extracted to the two iron loss power calculation units 45, 46.

The total power loss calculation unit 53 multiplies the reactor voltage signal S41 output from the signal phase shift processing unit 41 and the reactor current signal S42 output from the signal phase shift processing unit 42 based on the AC period Tac to obtain the total loss S53, and a subtractor 54 is connected to its output side. The subtractor 54 inputs the total loss S53 and the reactor high frequency iron loss S45 output from the iron loss power calculation unit 45, subtracts the reactor high frequency iron loss S45 from the total loss S53 to obtain the copper loss S54, and provides it to the calculation result recording unit 47. The calculation result recording unit 47 is composed of a memory, a register, etc. that records the provided reactor high frequency iron losses S45, S46 and copper loss S54.

(Operation of the Three-Phase Inverter of the Second Embodiment)
The three-phase inverter 2 in FIG. 11A operates in the same manner as the three-phase inverter 2 in the first embodiment shown in FIG.
In an actual circuit environment, a phase error calibration method and a reactor loss measurement method using the reactor loss measurement device 30A are performed as follows.

(Phase error calibration method according to the second embodiment)
FIG. 12 is a functional block diagram of a phase error calibration power calculation device for executing the phase error calibration method using the measurement device main body 40B of FIG. 11(b).
In this phase error calibration power calculation device 40C, two switching frequency high frequency component extraction units 51 and 52 are added to the phase error calibration power calculation device 40A of the first embodiment shown in FIG.

In the phase error calibration process using the phase error calibration power calculation device 40C of this embodiment 2, the reactor voltage vl and reactor current il are measured by the voltage meter 31 and current meter 32, and a voltage measurement signal S31 and a current measurement signal S32 are obtained. Note that measurements may be made using another waveform measurement device, and the voltage measurement signal and current measurement signal may be obtained by communication or data copy.

Next, the iron loss phase characteristic calculation unit 48 performs the same iron loss phase characteristic calculation process as in Example 1 to obtain the phase parameters ps1 and ps2. The signal phase shift processing units 41 and 42 perform phase processing on the voltage measurement signal S31 and the current measurement signal S32 based on the phase parameters ps1 and ps2, and output the reactor voltage signal S41 and the reactor current signal S42. The switching frequency high frequency component extraction units 51 and 52 extract the switching frequency high frequency components from the reactor voltage signal S41 and the reactor current signal S42. The switching component voltage signal S51 and the switching component current signal S52 from which the high frequency components have been extracted are multiplied by the iron loss power calculation unit 45 to obtain the reactor high frequency iron loss S45, which is recorded in the calculation result recording unit 47. After that, the phase error calibration calculation unit 49 performs the phase error calibration calculation process, and the phase error calibration result S49 is output, recorded and displayed, and the phase error calibration process is completed.

(Method of Measuring Reactor Loss in Example 2)
In the reactor loss measuring method of the present embodiment 2, the above-mentioned phase error calibration process is performed, and then the reactor loss calculation process is performed. Then, the reactor loss calculation result is output, recorded and displayed, and the reactor loss calculation process is terminated.

(Input Filter of Second Embodiment)
FIG. 13 is an explanatory diagram of input filters 55 and 56 provided between the voltage measuring device 31 and the current measuring device 32 and the signal phase shift processing units 41 and 42.
A configuration may be adopted in which an input filter 55 removes high-frequency signals due to stray capacitance from a voltage measurement signal S31 measured by a voltage measuring device 31 before inputting the signal to a signal phase shift processing unit 41, and an input filter 56 removes high-frequency signals due to stray capacitance from a current measurement signal S32 measured by a current measuring device 32 before inputting the signal to a signal phase shift processing unit 42. This improves the accuracy of calculation.

(Effects of Example 2)
The second embodiment has substantially the same effects as the first embodiment.

(Modification of Examples 1 and 2)
(i) The measuring device main body 40B in FIG. 11(b) and the phase error calibration power calculation device 40C in FIG. 12 can also be applied to the three-phase inverter 2 in FIG. 1(a).
(ii) The measurement device main body 40 in FIG. 1B, the measurement device main body 40B in FIG. 11B, the phase error calibration power calculation device 40A in FIG. 4, and the phase error calibration power calculation device 40C in FIG. 12 may be changed to configurations other than those shown in the drawings.
(iii) The input filters 55 and 56 in FIG. 13 may be provided on the output side of the voltage measuring device 31 and the current measuring device 32 in FIG.

In the above first and second embodiments, the three-phase inverter 2 has been described as the circuit to be measured. However, the reactor loss measuring device of the present invention can be applied to various circuits as the circuit to be measured, such as a single-phase inverter, a three-phase PFC circuit, and a single-phase PFC circuit.
For example, Fig. 14 is a circuit diagram showing a configuration example of a single-phase inverter 2A. In this single-phase inverter 2A, DC power from a DC power source 1 is converted into AC power by switching using a switching circuit 10A having a plurality of switches 11 to 14. A load 3 or a system power source is connected to the output side of the switching circuit 10A via an output filter 20A consisting of a reactor 21 and a capacitor 24. In such a single-phase inverter 2A, a reactor voltage vl applied across both ends of the reactor 21 and a reactor current il flowing through the reactor 21 are measured by the reactor loss measuring device 30 in Fig. 1 or the reactor loss measuring device 30A in Fig. 11, and the reactor iron loss can be calculated.

Figure 15 is a circuit diagram showing an example of the configuration of a three-phase PFC circuit 2B. In this three-phase PFC circuit 2B, three-phase AC power from a three-phase AC power source 1A is input via an input filter 20B consisting of reactors 21-23 and capacitors 24-26, and is converted to DC power by a switching circuit 10B consisting of multiple switches 11-16. The DC power with an improved power factor is then supplied to a load 3. In such a three-phase PFC circuit 2B, the reactor voltage vl applied across the reactor 21 and the reactor current il flowing through the reactor 21 are measured by the reactor loss measuring device 30 in Figure 1 or the reactor loss measuring device 30A in Figure 11, and the reactor iron loss can be calculated.

Figure 16 is a circuit diagram showing an example of the configuration of a single-phase PFC circuit 2C. In this single-phase PFC circuit 2C, AC power from an AC power source 1B is input via an input filter 20C consisting of a reactor 21 and a capacitor 24, and is converted to DC power by a switching circuit 10C consisting of multiple switches 11 to 14. The DC power with an improved power factor is then supplied to a load 3. In such a single-phase PFC circuit 2C, the reactor voltage vl applied across both ends of the reactor 21 and the reactor current il flowing through the reactor 21 are measured by the reactor loss measuring device 30 in Figure 1 or the reactor loss measuring device 30A in Figure 11, and the reactor iron loss can be calculated.

2 Three-phase inverter 2A Single-phase inverter 2B Three-phase PFC circuit 2C Single-phase PFC circuit 10, 10A, 10B, 10C Switching circuit 11-16 Switch 20, 20A Output filter 20B, 20C, 55, 56 Input filter 21-23 Reactor 24-26 Capacitor 27 Secondary winding 30, 30A Reactor loss measuring device 31 Voltage measuring device 32 Current measuring device 33 Measurement recording device 34 Calculation device 40, 40B Measurement device main body 40A, 40C Phase error calibration power calculation device 41, 42 Signal phase shift processing unit 43 Switching frequency calculation unit 44 Switching period calculation unit 45, 46 Iron loss power calculation unit 47 Calculation result recording unit 48 Iron loss phase characteristic calculation unit 49 Phase error calibration calculation unit 51, 52 Switching frequency high frequency component extraction unit 53 Total power loss calculation unit

Claims (9)

a reactor loss measurement device configured to measure a reactor voltage and a reactor current of a filter reactor provided on the output side or the input side of a switching circuit that performs switching by a high-frequency drive signal to perform power conversion, to obtain a measurement signal on a time axis , to calculate a phase error on the time axis of the measurement circuit using the measurement signal, to perform a phase adjustment of the phase error, and to calculate a reactor loss by a power calculation of the reactor signal, wherein the reactor loss measurement device is configured to perform signal phase shift processing by shifting the phase of the reactor voltage or the reactor current within a predetermined range, and to calculate the phase error on the time axis of the measurement circuit based on the relationship between the amount of phase shift on the time axis in the signal phase shift processing and a power value calculation result, to calculate a power amount change rate corresponding to each of the phase shift amounts using a plurality of the phase shift amounts on the time axis and the power value calculation result, and to calculate the phase shift amount on the time axis corresponding to the minimum value of the power amount change rate as the phase error. a reactor loss measurement device configured to measure a reactor voltage and a reactor current of a filter reactor provided on an output side or an input side of a switching circuit that performs switching by a high-frequency drive signal to perform power conversion to obtain a measurement signal, calculate a phase error of the measurement circuit using the measurement signal, perform a phase adjustment of the phase error, and calculate a reactor loss by power calculation of the reactor signal, wherein the reactor loss measurement device is configured to perform signal phase shift processing by shifting the phase of the reactor voltage or the reactor current within a predetermined range, and calculate the phase error of the measurement circuit based on the relationship between the phase shift amount in the signal phase shift processing and a power value calculation result, calculate a power amount change rate corresponding to each of the phase shift amounts using a plurality of the phase shift amounts and the power value calculation result, and obtain a second-order polynomial approximation function P(t) of the power amount change rate by the following formula using the values of the plurality of phase shift amounts and the power amount change rate, with the phase error amount corresponding to the minimum value of the power amount change rate being centered on the calculated phase error value, and calculate the phase error as -p2/p1/2. The quadratic polynomial approximation function P(t) of the following formula is found, and the phase error is converted into time using tmin = -p2/p1/2: P(t) = p1 * t^2 + p2 * t + p3 , where t is the time converted value t (ns) of the phase shift, and p1, p2, and p3 are coefficients of the quadratic polynomial approximation function P(t). The reactor loss measuring device according to claim 1 or 2, characterized in that a secondary winding for measurement is provided in the reactor and the reactor voltage is measured. The reactor loss measurement device according to claim 2, characterized in that the calculation to obtain the quadratic polynomial approximation function is repeated a predetermined number of times. 3. The reactor loss measuring device according to claim 1, wherein the phase error is used as a parameter for signal phase shift processing, and a reactor high frequency iron loss is calculated for each switching period of the drive signal. 3. The reactor loss measuring device according to claim 1, wherein the phase error is used as a parameter for signal phase shift processing to calculate high frequency core loss of a reactor in an AC cycle. 3. The reactor loss measuring device according to claim 1, wherein the phase error is used as a parameter for signal phase shift processing, and a total reactor loss and copper loss in an AC cycle are calculated. A reactor loss measurement device as claimed in any one of claims 1 to 7, characterized in that the measurement signal is obtained by removing high-frequency signals from the measured reactor voltage and reactor current. A waveform measuring device having the functions of the reactor loss measuring device according to any one of claims 1 to 8.

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