JP7514719B2 - Reactor loss calculation method, reactor loss measurement device, and waveform measurement device - Google Patents

Description

The present invention relates to a reactor loss calculation method, a reactor loss measurement device, and a waveform measurement device for a switching power supply device having a filter reactor.

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, so it is essential to measure losses in magnetic components in order to further reduce losses.

Patent Document 1 discloses an iron loss measurement device for magnetic materials that measures iron loss by adding a secondary measurement winding in a dedicated excitation circuit. Patent Document 2 discloses a reactor loss measurement device and measurement method that adds a secondary measurement winding to a filter reactor in a single-phase inverter and measures reactor loss in a real circuit environment. Furthermore, Non-Patent Document 1 discloses a reactor loss measurement method that adds a secondary measurement winding to a filter reactor in a three-phase inverter and measures reactor loss with a dedicated measuring device.

Japanese Patent Application Laid-Open No. 01-285881 JP 2008-122210 A

IEEE TRANSACTIONS ON POWER ELECTRONICS, 31[4] (2016-4) (US) p. 3080-3095

The magnetic body iron loss measurement device disclosed in Patent Document 1 adds a secondary measurement winding to measure iron loss, so a dedicated circuit is required. The reactor loss measurement device and measurement method disclosed in Patent Document 2 measure reactor loss in an actual circuit environment, but it requires the addition of a secondary measurement winding and measures reactor loss using the intersection of the reactor current signal and the current fundamental wave signal, so it cannot be applied to three-phase inverters, which have complex current waveforms. In addition, the reactor loss measurement method disclosed in Non-Patent Document 1 requires a dedicated measurement device and an inverter control circuit synchronized with the signal from this dedicated measurement device, so it cannot be used to measure when installed in an actual device.

The reactor loss calculation method of the present invention is a reactor loss calculation method for calculating reactor high frequency iron loss of a filter reactor provided on the output side or the input side of a switching circuit that performs power conversion by switching in response to a high frequency switching signal, the method comprising the steps of: calculating a switching frequency by performing fast Fourier transform analysis on a reactor current flowing through the reactor; calculating a switching period from the switching frequency; extracting a switching component signal by removing low frequency components from a measurement signal obtained by measuring a reactor voltage and a reactor current of the reactor based on the switching period ; and calculating the reactor high frequency iron loss by performing power calculation on the switching component signal.

The reactor loss measuring device of the present invention is a reactor loss measuring device that measures high frequency iron loss in a reactor for a filter provided on the output side or input side of a switching circuit that performs power conversion by switching with a high frequency switching signal , and calculates a switching frequency by performing fast Fourier transform analysis on a reactor current flowing through the reactor, calculates a switching period from the switching frequency, and calculates a switching loss based on the switching period.
The method is characterized in that a low-frequency component of a measurement signal obtained by measuring a reactor voltage and a reactor current of the reactor is removed to extract a switching component signal, and the reactor high-frequency iron loss is calculated by performing a power calculation on the switching component signal.
Another reactor loss measurement device of the present invention is a reactor loss measurement device that measures high frequency iron loss in a reactor for a filter provided on the output side or input side of a switching circuit that performs power conversion by switching using a high frequency switching signal, and is characterized in that the device measures a reactor voltage and a reactor current of the reactor to obtain a measurement signal, calculates an average value of 1/2 switching cycles before and after the switching signal or an integer multiple of the 1/2 switching cycles before and after the switching signal centered on the time of the measurement signal, subtracts the average value from the measurement signal to calculate a switching component signal, and measures the high frequency iron loss of the reactor by performing power calculation of the switching component signal.

The waveform measuring device of the present invention is a device for measuring waveforms, such as an oscilloscope, that has the calculation function of the reactor loss measuring device.

According to the present invention, the low-frequency components of the measurement signal that measures the reactor voltage and reactor current are removed, and the reactor high-frequency iron loss is calculated by power calculation of the switching component signal, so there is no need to add a secondary measurement winding and high-frequency iron loss can be measured with high accuracy. Moreover, since the low-frequency components are removed when extracting the switching component signal, the effects of copper loss can be eliminated and it is also effective in preventing measurement error fluctuations. Furthermore, since no dedicated circuit is required and measurements can be made while the actual equipment is operating, it can be applied to reactor loss measurements in three-phase inverters, single-phase inverters, DC/DC converters, PFC circuits, etc.

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 functional block diagram showing a configuration example of a switching frequency high-frequency component extraction unit 45 in FIG. 1 . FIG. 2 is a functional block diagram showing a configuration example of an iron loss power calculation unit 47 in FIG. 1 . FIG. 2 is a waveform diagram showing a switching frequency calculation method in the switching frequency calculation unit 43 in FIG. 1. FIG. 3 is a waveform diagram for explaining the switching frequency high frequency component extraction function of FIG. 2. Enlarged view of the waveform in FIG. FIG. 11 is a functional block diagram showing a configuration example of a switching frequency high-frequency component extraction unit 45 according to a second embodiment of the present invention. FIG. 11 is a functional block diagram showing a configuration example of a switching frequency high frequency component extraction unit 45 according to a third embodiment of the present invention. A circuit diagram showing a configuration example of a single-phase inverter 2A. A circuit diagram showing a configuration example of a three-phase PFC circuit 2B. A circuit diagram showing a configuration example of a single-phase PFC circuit 2C. Circuit diagram showing an example of the configuration of a single reactor as the circuit to be measured

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).

In FIG. 1(a), a three-phase inverter 2 that performs three-phase DC/AC conversion is connected to a DC power source 1, and the 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 switching 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 reactor loss measuring device 30 is connected to the reactor 21.

The reactor loss measuring device 30 is a device that measures the reactor high-frequency iron loss of the reactor 21, 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 meter 31 that measures the reactor voltage vl applied to both ends of the reactor 21, and a current meter 32 that measures the reactor current il flowing through the reactor 21. The voltage meter 31 is composed of, for example, a voltage probe for an oscilloscope. The current meter 32 is composed of, for example, a current probe for an oscilloscope, a shunt resistance measuring circuit, etc. The measurement signal (e.g., voltage measurement signal) S31 of the reactor voltage vl measured by the voltage meter 31 and the measurement signal (e.g., current measurement signal) S32 of the reactor current il measured by the current meter 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 determines the reactor high-frequency iron loss by calculation, and is composed of, for example, the calculation function in an 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 recorder 33 and the arithmetic unit 34 of FIG.
The measuring device main body 40 removes low-frequency components from the voltage measurement signal S31 to extract a switching component signal (e.g., a switching component voltage signal) S45, and removes low-frequency components from the current measurement signal S32 to extract a switching component signal (e.g., a switching component current signal) S46, and measures reactor high-frequency iron losses S47, S48 by performing power calculation (=S45×S46) on the switching component voltage signal S45 and the switching component current signal S46. The measuring device main body 40 has a signal phase-shift processing section 41 that inputs the voltage measurement signal S31 measured by the voltage meter 31, and a signal phase-shift processing section 42 and a switching frequency calculation section 43 that input the current measurement signal S32 measured by the current meter 32.

The signal phase-shifting processing unit 41 changes the phase of the input voltage measurement signal S31 based on the phase-shifting parameter ps1, performs processing to make it coincide with the phase of the current measurement signal S32, and outputs the voltage signal S41. The signal phase-shifting processing unit 42 changes the phase of the input current measurement signal S32 based on the phase-shifting parameter ps2, performs processing to make it coincide with the phase of the voltage measurement signal S31, and outputs the current signal S42. In order to make the phases of the voltage signal S41 and the current signal S42 coincide with each other, for example, the two signal phase-shifting processing units 41 and 42 set the phase of one of the voltage signal S41 and the current signal S42 to zero. 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 of this unit. The switching period calculation unit 44 calculates the switching period Tsw from 1/fsw.

The signal phase shifting processing units 41 and 42 are connected to switching frequency high frequency component extraction units 45 and 46, respectively. The switching frequency high frequency component extraction unit 45 removes low frequency components from the voltage signal S41 output from the signal phase shifting processing unit 41 based on the switching period Tsw, extracts switching frequency high frequency components, and outputs a switching component signal (e.g., switching component voltage signal) S45, and the iron loss power calculation units 47 and 48 are connected to the output side. The other switching frequency high frequency component extraction unit 46 removes low frequency components from the current signal S42 output from the signal phase shifting processing unit 42 based on the switching period Tsw, extracts switching frequency high frequency components, and outputs a switching component signal (e.g., switching component current signal) S46, and the iron loss power calculation units 47 and 48 are connected to the output side.

One of the iron loss power calculation units 47 calculates the reactor high frequency iron loss S47 by power calculation (= S45 x S46) between the switching component voltage signal S45 and the switching component current signal S46 based on the switching period Tsw, and the calculation result recording unit 49 is connected to the output side. The other iron loss power calculation unit 48 calculates the reactor high frequency iron loss S48 by power calculation (= S45 x S46) between the switching component voltage signal S45 and the switching component current signal S46 based on the AC period Tac, and the calculation result recording unit 49 is connected to the output side. The calculation result recording unit 49 is composed of a memory, a register, etc. that records the calculated reactor high frequency iron losses S47, S48.

FIG. 2 is a functional block diagram showing an example of the configuration of the switching frequency high frequency component extraction unit 45 shown in FIG.
The switching frequency high frequency component extraction unit 45 has a delay processing unit 45a, a low pass filter 45b, and a subtractor 45c. The input voltage signal S41 is subjected to a delay processing corresponding to a low pass filter time constant by the delay processing unit 45a, and the low frequency component is extracted by the low pass filter 45b. The low frequency component is subtracted from the delay processing result by the subtractor 45c, and the switching component voltage signal S45 is output.

The other switching frequency high frequency component extraction unit 46 in FIG. 1 is configured in a manner similar to the switching frequency high frequency component extraction unit 45, in that the input current signal S42 is subjected to a delay processing unit that is equivalent to a low pass filter time constant, and low frequency components are extracted by a low pass filter, and the low frequency components are subtracted from the delay processing result by a subtractor, and a switching component current signal S46 is output.

FIG. 3 is a functional block diagram showing an example of the configuration of the iron loss power calculation unit 47 in FIG.
The iron loss power calculation unit 47 has a multiplier 47a and an average calculation unit 47b for a specified period T. The multiplier 47a multiplies a voltage signal V(t) which is the input switching component voltage signal S45 by a current signal i(t) which is the input switching component current signal S46, and the average calculation unit 47b for the specified period T calculates the following equation (1) on the result of this multiplication to calculate a power value P which is the reactor high frequency iron loss S47.
Here, in the average calculation section 47b of the designated period T, T is the calculation period (that is, the switching period Tsw or a multiple thereof).

Another iron loss power calculation unit 48 in FIG. 1 is configured in a manner similar to the iron loss power calculation unit 47 in that a voltage signal V(t), which is an input switching component voltage signal S45, is multiplied by a multiplier by a current signal i(t), which is an input switching component current signal S46, and an average calculation unit for a specified period T performs the calculation of the above formula (1) on the result of this multiplication, thereby calculating a power value P, which is a reactor high frequency iron loss S48.
Here, in the average calculation unit for the specified period T, T is the calculation period (i.e., the AC period Tac 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 22 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, the high-frequency iron loss of the reactor 21 is measured by the reactor loss measuring device 30 as follows.

(Reactor Loss Calculation Method in First Embodiment)
4(a) and (b) are waveform diagrams showing a switching frequency calculation method in the switching frequency calculation unit 43 in Fig. 1, where Fig. 4(a) is a waveform diagram showing an FFT analysis of a current measurement signal S32 at a reactor current il, and Fig. 4(b) is a waveform diagram showing an FFT analysis of a voltage measurement signal S31 at a reactor voltage vl. Figs. 5(a) and (b) are waveform diagrams for explaining the switching frequency high frequency component extraction function in Fig. 2. Furthermore, Fig. 6 is an enlarged view of the waveform in Fig. 5.

When the three-phase inverter 2 operates, a reactor voltage vl is applied to both ends of the reactor 21, and a reactor current il flows through the reactor 21. The reactor voltage vl is measured by the voltage meter 31 shown in FIG. 1, and the reactor current il is measured by the current meter 32. The voltage measurement signal S31 measured by the voltage meter 31 is input to the signal phase shift processing unit 41 in the measurement device main body 40, and further, the current measurement signal S32 measured by the current meter 32 is input to the signal phase shift processing unit 42 and the switching frequency calculation unit 43.

The signal phase shift processing unit 41 performs phase processing on the input voltage measurement signal S31 based on the phase parameter ps1 to match the phase of the current measurement signal S32, and outputs the resultant voltage signal S41, which is input to the switching frequency high frequency component extraction unit 45. The other signal phase shift processing unit 42 performs phase processing on the input current measurement signal S32 based on the phase parameter ps2 to match the phase of the voltage measurement signal S31, and outputs the resultant current signal S42, which is input to the other switching frequency high frequency component extraction unit 46. At the same time, the switching frequency calculation unit 43 performs FFT analysis on the input current measurement signal S32 to calculate the switching frequency fsw, and inputs the switching frequency fsw to the switching period calculation unit 44. The switching period calculation unit 44 calculates the switching period Tsw (=1/fsw) from the reciprocal of the switching frequency fsw.

Figure 4(a) shows the result of FFT analysis of the current measurement signal S32 at the reactor current il. It can be seen that the current measurement signal S32 of the reactor current il is maximum at two frequencies f1 and f2. In the result of FFT analysis of the voltage measurement signal S31 at the reactor voltage vl shown in Figure 4(b), the voltage measurement signal S31 of the reactor voltage vl is maximum at two frequencies f1 and f2, and its shape is almost the same as the current measurement signal S32 of the reactor current il. Therefore, in Figure 1(b), the switching frequency calculation unit 43 and the switching period calculation unit 44 may be changed to a circuit configuration that inputs the voltage measurement signal S31.

The switching frequency high frequency component extraction unit 45 removes the switching frequency low frequency components of the input voltage signal S41 based on the switching period Tsw, extracts the switching frequency high frequency components to calculate the switching component voltage signal S45, and inputs the switching component voltage signal S45 to the two iron loss power calculation units 47, 48. For example, as shown in FIG. 2, the switching frequency high frequency component extraction unit 45 performs delay processing equivalent to the low pass filter time constant on the voltage signal S41 by the delay processing unit 45a, and the low pass filter 45b extracts the low frequency components of the voltage signal S41. Then, the subtractor 45c subtracts the extracted low frequency components from the processing result of the delay processing unit 45a to calculate the switching component voltage signal S45. The operating waveforms of this switching frequency high frequency component extraction unit 45 are shown in FIG. 5 and FIG. 6.

At the same time, the other switching frequency high frequency component extraction unit 46 also removes the switching frequency low frequency components from the input current signal S42 based on the switching period Tsw, extracts the switching frequency high frequency components, calculates the switching component current signal S46, and inputs the switching component current signal S46 to the two iron loss power calculation units 47, 48.

On the other hand, the iron loss power calculation unit 47 performs a power calculation (= S45 x S46) on the input switching component voltage signal S45 and switching component current signal S46 based on the switching period Tsw, calculates the reactor high frequency iron loss S47, and inputs the reactor high frequency iron loss S47 to the calculation result recording unit 49. For example, as shown in FIG. 3, the iron loss power calculation unit 47 multiplies the input switching component voltage signal S45, which is the voltage signal V(t), by the switching component current signal S46, which is the current signal i(t), by the multiplier 47a, and performs an average calculation for the specified period T as shown in formula (1) on the multiplication result by the specified period T average calculation unit 47b, and calculates the power value P, which is the reactor high frequency iron loss S47.

At the same time, the other iron loss power calculation unit 48 also performs a power calculation (=S45×S46) on the input switching component voltage signal S45 and switching component current signal S46 based on the AC period Tac to calculate the reactor high frequency iron loss S48, and inputs the reactor high frequency iron loss S48 to the calculation result recording unit 49. In the iron loss power calculation unit 48, similar to the iron loss power calculation unit 47 in Fig. 3, for example, a multiplier is used to multiply the voltage signal V(t) which is the input switching component voltage signal S45 by the current signal i(t) which is the switching component current signal S46, and an average calculation unit for the specified period T performs an average calculation for the multiplication result as shown in Equation (1) for the specified period T, and a power value P which is the reactor high frequency iron loss S48 is calculated.
The calculation result recording unit 49 records the two input reactor high frequency iron losses S47, S48, and ends the reactor loss measurement process.

(Effects of Example 1)
According to the first embodiment, the following effects (1) to (4) are obtained.
(1) After low frequency components are removed from a voltage measurement signal S31 of the reactor voltage vl measured by the voltage meter 31 and a current measurement signal S32 of the reactor current il measured by the current meter 32 by switching frequency high frequency component extraction units 45, 46, the reactor high frequency iron losses S47, S48 are calculated by power calculation of the switching component voltage signal S45 and the switching component current signal S46 by iron loss power calculation units 47, 48. Therefore, there is no need to add a secondary measurement winding, and high frequency iron losses can be measured with high accuracy.

(2) When extracting the switching component signal, low-frequency components are removed, so the effects of copper loss can be eliminated.
That is, the copper loss of the reactors 21 to 23 is classified into a portion due to low frequency components and a portion due to high frequency components. The copper loss due to the high frequency component current flowing through the reactors 21 to 23 is small, for example, about 1% or less of the iron loss, and can be ignored as an error. In contrast, the copper loss due to the low frequency component current is large, but the low frequency components are removed by filtering in the switching frequency high frequency component extractors 45 and 46, so the influence of the copper loss can be eliminated. Therefore, there is no need to add a secondary measurement winding, and high frequency iron loss can be measured with high accuracy.

(3) When the switching component signal is extracted, low-frequency components are removed, which is also effective in reducing measurement error fluctuations.
That is, when the measurement circuit of the reactor loss measurement device 30 is configured with, for example, an oscilloscope, a voltage probe, and a current probe, the error fluctuation of the measurement circuit is classified into frequency components lower than the switching frequency fsw, the switching frequency fsw and related harmonic components, and frequency components higher than the switching frequency fsw. Among these, the high frequency components can be removed by the integration process of the power calculation in the iron loss power calculation units 47, 48. The switching frequency components depend on the characteristics of the voltage probe and the current probe. Therefore, by removing the low frequency components, the influence of copper loss can be removed and it is also effective in dealing with errors in the measurement circuit.

(4) Since no dedicated circuit is required and measurements can be made while the actual equipment is in operation, it can be applied to measuring reactor losses in switching power supplies such as three-phase inverters, single-phase inverters, DC/DC converters, and PFC circuits.

FIG. 7 is a functional block diagram showing a configuration example of the switching frequency high frequency component extracting unit 45 in the second embodiment of the present invention.
The switching frequency high frequency component extraction unit 45 of the second embodiment is composed of an average calculation unit 45d that performs an average calculation of an integer multiple period of a switching cycle on the input voltage signal S41, and a subtractor 45c. In this switching frequency high frequency component extraction unit 45, the average calculation unit 45d performs an average calculation of an integer multiple period of a switching cycle on the input voltage signal S41, as shown in the following equation (2).
t-Tsw/2*N to t+Tsw/2*N (2)
Where, Tsw is the switching period.
N=1, 2, ...
Then, the subtractor 45c subtracts the calculation result of the equation (2) from the input voltage signal S41, and outputs a switching component voltage signal S45.

The other switching frequency high frequency component extraction unit 46 is similarly configured with an average calculation unit that performs an average calculation for an integer multiple period of the switching cycle on the input current signal S42, and a subtractor. In this switching frequency high frequency component extraction unit 46, the average calculation unit performs an average calculation for an integer multiple period of the switching cycle on the input current signal S42, and the subtractor subtracts the calculation result of the average calculation unit from the input current signal S42, and outputs a switching component current signal S46.

Even with a measurement device main body 40 having such switching frequency high frequency component extraction units 45, 46, it is possible to achieve substantially the same effect as in Example 1.

FIG. 8 is a functional block diagram showing a configuration example of the switching frequency high frequency component extracting unit 45 in the third embodiment of the present invention.
The switching frequency high frequency component extraction unit 45 of the third embodiment is composed of a delay processing unit 45e that performs delay processing on the input voltage signal S41, an average calculation unit 45f that performs average calculation on the input voltage signal S41 over an integer multiple period of the switching cycle, and a subtractor 45c. In this switching frequency high frequency component extraction unit 45, the delay processing unit 45e performs delay processing on the input voltage signal S41 according to the following equation (3).
Tsw/2*N (3)
Where, Tsw is the switching period.
N=1, 2, ...

At the same time, the average calculation unit 45f performs an average calculation of the input voltage signal S41 over an integral multiple period of the switching cycle, as shown in the following equation (4).
t - Tsw / 2 * N to t (4)
Where, Tsw is the switching period.
N=1, 2, ...
Then, the subtractor 45c subtracts the calculation result of the average calculation section 45f from the processing result of the delay processing section 45e, and outputs a switching component voltage signal S45.

The other switching frequency high frequency component extraction unit 46 is similarly composed of a delay processing unit that performs delay processing on the input current signal S42, an average calculation unit that performs an average calculation for an integer multiple period of the switching cycle on the input current signal S42, and a subtractor. In this switching frequency high frequency component extraction unit 46, the delay processing unit performs delay processing on the input current signal S42. At the same time, the average calculation unit performs an average calculation for an integer multiple period of the switching cycle on the input current signal S42. Then, the subtractor subtracts the calculation result of the average calculation unit from the processing result of the delay processing unit, and outputs the switching component current signal S46.

Even with a measurement device main body 40 having such switching frequency high frequency component extraction units 45, 46, it is possible to achieve substantially the same effect as in Example 1.

In the above embodiments 1 to 3, a three-phase inverter was described as the circuit to be measured, but the reactor loss measurement device 30 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. 9 is a circuit diagram showing an example of the configuration of a single-phase inverter 2A. In this single-phase inverter 2A, the DC power of the DC power source 1 is converted to AC power by switching using a switching circuit 10A having multiple 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, the reactor voltage vl applied to 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 FIG. 1, and the reactor high-frequency iron loss can be calculated.

Figure 10 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 1B is input via an input filter 20B consisting of inductors 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, and the reactor high-frequency iron loss can be calculated.

Figure 11 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 1C is input via an input filter 20C consisting of an inductor 21 and a capacitor 24, and is converted to DC power by a switching circuit 10C consisting of multiple switches 11-14. 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, and the reactor high-frequency iron loss can be calculated.

Figure 12 is a circuit diagram showing an example of the configuration of a single reactor as the circuit to be measured. If a secondary measurement winding is added to the reactor 21, and a high-frequency power source 1E is connected to the reactor 21, the output voltage vl of the secondary measurement winding and the reactor current il flowing through the reactor 21 are measured using the reactor loss measurement device 30 in Figure 1, this is an effective measure against measurement instrument error fluctuations.

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 Switches 11a-16a Diodes 20, 20A Output filter 20B, 20C Input filter 21-23 Reactors 24-26 Capacitors 30 Reactor loss measuring device 31 Voltage measuring instrument 32 Current measuring instrument 33 Measurement and recording device 34 Calculation device 40 Measurement device main body 41, 42 Signal phase shift processing unit 43 Switching frequency calculation unit 44 Switching period calculation unit 45, 46 Switching frequency high frequency component extraction unit 47, 48 Iron loss power calculation unit 49 Calculation result recording unit

Claims (8)

A reactor loss calculation method for calculating high frequency iron loss of a reactor for a filter provided on an output side or an input side of a switching circuit that performs power conversion by switching using a high frequency switching signal, comprising:
A switching frequency is calculated by performing a fast Fourier transform analysis on a reactor current flowing through the reactor, and a switching period is calculated from the switching frequency.
a low-frequency component of a measurement signal obtained by measuring a reactor voltage and a reactor current of the reactor based on the switching period is removed to extract a switching component signal, and the reactor high-frequency iron loss is calculated by performing a power calculation on the switching component signal. A reactor loss measuring device for measuring high frequency iron loss of a reactor for a filter provided on an output side or an input side of a switching circuit for performing power conversion by switching with a high frequency switching signal,
A switching frequency is calculated by performing a fast Fourier transform analysis on a reactor current flowing through the reactor, and a switching period is calculated from the switching frequency.
extracting a switching component signal by removing a low frequency component of a measurement signal obtained by measuring a reactor voltage and a reactor current of the reactor based on the switching period ;
A reactor loss measuring device, comprising: a reactor loss measuring device for measuring the reactor high frequency iron loss by performing a power calculation on the switching component signal. A reactor loss measuring device for measuring high frequency iron loss of a reactor for a filter provided on an output side or an input side of a switching circuit for performing power conversion by switching with a high frequency switching signal,
Measure a reactor voltage and a reactor current of the reactor to obtain a measurement signal;
a reactor loss measuring device which calculates an average value of 1/2 switching cycles before and after the switching signal or an integer multiple of the 1/2 switching cycles before and after the switching signal, centered on a time of the measurement signal, subtracts the average value from the measurement signal to calculate a switching component signal , and measures the reactor high frequency iron loss by performing power calculation on the switching component signal . 4. The reactor loss measuring device according to claim 3 , wherein the reactor high frequency iron loss is calculated and recorded for each switching period of the switching signal or for each multiple of the switching period. 4. The reactor loss measuring device according to claim 3 , wherein the reactor high frequency iron loss is calculated in an AC period or a multiple of the AC period. 6. The reactor loss measuring device according to claim 3 , wherein a switching frequency and a switching period of the switching signal are calculated by performing a fast Fourier transform on a measurement signal of the reactor current. 7. The reactor loss measuring device according to claim 3 , further comprising a phase shift process for the measurement signal. A waveform measuring device having a calculation function of the reactor loss measuring device according to any one of claims 3 to 7.

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