JP2017192255A - Electric power conversion system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power conversion system capable of estimating a reactor current with high precision without need for addition of a reactor current sensor.SOLUTION: An electric power conversion system 100 includes: a reactor 12 connected with a DC power supply 10; a first switching element 14 and a second switching element 16 for controlling a current running through the reactor 12; and a capacitor 18 for smoothing an output voltage from the reactor 12 and further includes an observer for estimating a reactor current irunning through the reactor 12 on the basis of a power supply voltage vof the DC power supply 10 and a terminal voltage vand an output current iof the capacitor 18.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power converter that boosts or steps down a DC voltage.

  A technique for estimating an output current in a power converter that outputs a DC input voltage by stepping up or down to a predetermined DC voltage is disclosed.

For example, a power conversion device is disclosed in which an upper arm switch and a lower arm switch are complementarily turned on / off to release energy stored in a reactor, thereby boosting or lowering an input voltage and supplying the load to a load. (Patent Document 1). In this technique, the current flowing through the reactor has a triangular waveform that repeatedly reciprocates between the maximum value I _max and the minimum value I _min , and outputs in both a period in which the output current I _est gradually increases and a period in which it gradually decreases. A process for estimating the current I _est is shown.

In addition, in a DC / DC converter that converts and outputs a battery voltage by switching control of a current flowing through a reactor connected to the battery using a pair of switching elements, a battery current i _b flowing from the battery to the reactor is estimated. An observer is disclosed (Patent Document 2).

JP-A-2015-165762 JP 2006-42536 A

By the way, in the process of estimating the output current I _est in Patent Document 1, the dead time during which both switches are turned off between the on operation time T _mon of the upper arm switch and the on operation time T _ron of the lower arm switch is considered. It has not been. Therefore, it is impossible to grasp the influence of the dead time on the estimation of the output current I _est . The influence of the dead time on the estimation of the output current I _est is not small, and the output current I _est cannot be estimated with high accuracy by this processing. Further, the output current because there is no feedback of the estimation results in estimating the I _est, reactor, capacitance, the estimation accuracy of the output current I _est due to the influence of the detection error of the voltage tends to decrease.

Further, in the observer in Patent Document 2, when the reactor current flows to more than ½ amplitude of the current ripple, due to dead time, between the command duty and the actual duty that is the ratio of the actual switching element on-time in the state equation. An error occurs, and the estimation accuracy of the battery current i _b decreases.

One aspect of the present invention includes a reactor connected to a power supply, a first switching element and a second switching element that control a current flowing through the reactor, and a capacitor that smoothes an output voltage from the reactor. and a power converter for DC power conversion, comprising an observer for estimating the power supply voltage v _b, the terminal voltage of the capacitor v _c and reactor current i _L flowing through the reactor on the basis of the output current i _m of the power source It is the power converter device characterized by the above.

In this case, the observer has an on-time of the first switching element and the second switching with respect to a state equation when the first switching element is on and a state equation when the second switching element is on. It is preferable to estimate the reactor current i _L by applying an on-time of an element and a dead time when the first switching element and the second switching element are simultaneously turned off.

  The observer is configured to turn on the first switching element and turn on the second switching element based on the duty of the on / off state of the first switching element and the second switching element and the triangular wave comparison PWM. It is preferable to calculate the dead time.

  In the dead time, the observer applies a state equation when the first switching element is on when the estimated value of the reactor current is positive, and the estimated value of the reactor current is negative. In this case, it is preferable to apply a state equation when the second switching element is in an ON state.

  Further, it is preferable that the observer is a disturbance observer to which a duty error generated during the dead time is added as a disturbance.

In addition, the observer, the power supply voltage is sampled at a timing synchronized with the period of the carrier signal v _b, as an input the output current i _m and capacitor voltage v _c, is possible to estimate the reactor current i _L for each of the timing Is preferred.

Further, it is preferable to estimate the reactor current i _L based on a three-phase voltage command of the inverter and a detected three-phase current value.

  ADVANTAGE OF THE INVENTION According to this invention, the power converter device which can estimate a reactor current with high precision, without adding a reactor current sensor can be provided.

It is a figure which shows the basic composition of the power converter device in embodiment of this invention. It is a figure which shows the whole structure of the observer in embodiment of this invention. It is a figure which shows the example of the triangular wave comparison pulse width modulation in embodiment of this invention. It is a figure which shows the structure of the 1st-4th observer in embodiment of this invention. It is a figure which shows the structure of the 5th observer in embodiment of this invention. It is a figure which shows the structure of the 2nd and 4th observer in embodiment of this invention. It is a figure explaining the estimation process of the capacitor | condenser voltage and reactor current in embodiment of this invention. It is a figure which shows the estimation result of a capacitor voltage and a reactor current. It is a figure which shows the estimation result of the reactor current by a prior art. It is a figure which shows the frequency response of the reactor current by a prior art. It is a figure which shows the estimation result of the reactor current in 1st Embodiment. It is a figure which shows the frequency response of the reactor current in 1st Embodiment. It is a figure which shows the estimation result of the reactor current in 2nd Embodiment. It is a figure which shows the frequency response of the reactor current in 2nd Embodiment.

<First Embodiment>
FIG. 1 shows a basic configuration of a power conversion device 100 according to an embodiment of the present invention. The power conversion apparatus 100 includes a DC power supply 10, a reactor 12, a first switching element 14, a second switching element 16, and a capacitor 18.

  One end of the reactor 12 is connected to the positive electrode of the DC power supply 10, and the connection point C of the first switching element 14 and the second switching element 16 is connected to the other end of the reactor 12. The other end of the first switching element 14 is connected to the output terminal (OUT +) to the load 102, and the other end of the second switching element 16 is connected to the negative electrode (OUT−) of the DC power supply 10. A capacitor 18 is connected between the output terminal and the negative electrode of the DC power supply 10 in order to smooth the voltage.

  In the present embodiment, the first switching element 14 and the second switching element 16 are NPN transistors. The first switching element 14 has a collector on the output end side and an emitter on the reactor 12 side. The second switching element 16 has a reactor 12 side as a collector and a DC power supply 10 negative electrode side as an emitter. A free-wheeling diode is connected in parallel to each of the first switching element 14 and the second switching element 16.

In the power conversion device 100, the reactor current i _L flows from the positive electrode to the negative electrode of the DC power supply 10 through the reactor 12 by turning the first switching element 14 off and the second switching element 16 on. As a result, energy is accumulated in the reactor 12. Next, by turning off the second switching element 16, the reactor current i _L is cut off, and a voltage higher than the voltage of the DC power supply 10 (battery voltage v _b ) is generated at the end of the reactor 12. capacitor 18 in accordance with a current flowing toward the output end is the charging capacitor voltage v _c and rises. The capacitor voltage v _c is applied to the load 102. Further, when the first switching element 14 is turned on, the reactor current i _L flows from the capacitor 18 to the positive electrode of the DC power supply 10. Thus, the capacitor voltage v _c is reduced. Output voltage, i.e. the capacitor voltage v _c of the power converter 100 is determined by the duty ratio which is the ratio of the on period of the first switching element 14 and second switching element 16.

In the present embodiment, power conversion device 100 includes an observer 200 for estimating reactor current i _L. FIG. 2 shows the overall configuration of the observer 200. The observer 200 includes a switching time calculator 20, a first observer 22, a second observer 24, a third observer 26, a fourth observer 28, and a fifth observer 30. In the following, the estimated value in the figure is shown with a superscript wavy line (tilde).

  The inter-switching time calculator 20 calculates the switching time of the first switching element 14 and the second switching element 16 when receiving the setting value of the duty of the power conversion device 100 from the outside. With reference to FIG. 3, the calculation of the switching time in the inter-switching time calculator 20 will be described.

The inter-switching time calculator 20 includes a first switching element 14 and a second switching element 14 based on a triangular wave having a predetermined period (indicated by a thick solid line in FIG. 3) and a triangular wave delayed by a dead time (indicated by a dotted line in FIG. 3). A pulse width modulation signal (PWM signal) for controlling on / off of the switching element 16 is obtained. Here, the time ΔT ₁ is defined from the lower point of the triangular wave until the first switching element 14 is switched from the on state to the off state. Further, after the time ΔT _{1 has} elapsed, a period from when the first switching element 14 is turned off to when the second switching element 16 is turned on is defined as a dead time time ΔT ₂ . Further, after the dead time ΔT _{2 has} elapsed, the time during which the second switching element 16 is in the ON state is defined as time ΔT ₃ . Further, after the time ΔT _{3 has} elapsed, the time from when the second switching element 16 is turned off to when the first switching element 14 is turned on is defined as a dead time time ΔT ₄ . Further, after the dead time ΔT _{4 has} elapsed, the time from when the first switching element 14 is turned on to when the second switching element 16 is turned off is defined as time ΔT ₅ . The inter-switching time calculator 20 obtains a PWM signal so as to be the on-time of the first switching element 14 and the second switching element 16 according to the input duty, and the corresponding times ΔT ₁ , ΔT ₃ , ΔT _5. And dead time times ΔT ₂ and ΔT ₄ are set. The first switching element 14 and the second switching element 16 of the power conversion apparatus 100 are controlled by PWM signals determined by the set times ΔT ₁ , ΔT ₃ , ΔT ₅ and dead time times ΔT ₂ , ΔT ₄ . The inter-switching time calculator 20 outputs the set times ΔT ₁ , ΔT ₃ , ΔT ₅ and dead time times ΔT ₂ , ΔT ₄ to the first observer 22 to the fifth observer 30, respectively.

The first observer 22, the second observer 24, the third observer 26, the fourth observer 28, and the fifth observer 30 are the power supply voltage v _b and output current i of the power converter 100 sampled in synchronization with the period of the carrier signal. _m and capacitor voltage v _c (corresponding to the output voltage) are input, and time ΔT ₁ , dead time time ΔT ₂ , time ΔT ₃ , and dead time time ΔT set by switching time calculator 20 are input. ₄ and an estimated value of the reactor current i _L at time ΔT ₅ is obtained. In this embodiment, it receives input measurements sampled at the control timing synchronized supply voltage v _b, the output current i _m and capacitor voltage v _c (corresponding to the output voltage) under point of the triangular wave in Fig. 3 Then, an estimated value of the reactor current i _L is obtained for each control timing.

When the 1st switching element 14 is an ON state, the state equation of the power converter device 100 is represented by Numerical formula (1). Here, r _L represents the resistance component of the reactor 12. In the following description, the time differential value is indicated with a superscript point (dot).

Applying bilinear transformation to the mathematical formula (1) for discretization can be expressed as the mathematical formula (2).

Further, coefficients A, B, and C can be defined as in Expression (3) with respect to Expression (2).

On the other hand, when the 1st switching element 14 is an OFF state, the state equation of the power converter device 100 is represented by Numerical formula (4).

Applying bilinear transformation to the mathematical formula (4) for discretization can be expressed as the mathematical formula (5).

Further, the coefficients A, B, and C can be defined as in Expression (6) with respect to Expression (5).

  Since the state equations in the power conversion device 100 are expressed as Equations (1) to (6), the first observer 22, the second observer 24, the third observer 26, and the fourth observer 28 are as shown in FIG. It becomes the composition. The fifth observer 30 has a configuration as shown in FIG.

However, the second observer 24 for estimating the dead time time ΔT ₂ includes two observers 40 and 42 and a changeover switch 44 therein as shown in FIG. The observer 40 is an observer that estimates the reactor current i _L using the state equation when the first switching element 14 is in the on state, and the observer 42 represents the state equation when the first switching element 14 is in the off state. It is an observer that uses this to estimate the reactor current i _L. When the estimated value of the input reactor current i _L is a positive current (in the direction of flowing out from the positive electrode of the DC power supply 10), the first switching element 14 is equivalent to the on state, so the changeover switch 44 is switched to the observer 40 side. The reactor current i _L is estimated using the observer 40. When the estimated value of the input reactor current i _L is a negative current (in the direction of flowing into the positive electrode of the DC power supply 10), the first switching element 14 is equivalent to the off state, so the changeover switch 44 is switched to the observer 42 side. The reactor current i _L is estimated using the observer 42. The fourth observer 28 for estimating the dead time time ΔT ₄ may have the same configuration.

For example, the first observer 22 receives the time ΔT ₁ during which the first switching element 14 is in the on state from the lower point of the triangular wave until the first switching element 14 is switched from the on state to the off state. The first observer 22 receives an input of time [Delta] T _1, T the time [Delta] T ₁ state equation with the first switching element 14 is turned on (Equation (2) and Equation (3)), v _c (t ) the estimated value v _c of the previous capacitor voltage v _c in the fifth observer 30 (tilde) ([Delta] t _5), v _b (t) to the measured value of the supply voltage v _b, i _m (t) to the output current i Substituting the measured value of _m , the estimated value i _L (tilde) (ΔT ₁ ) of the reactor current i _L and the estimated value v _c (tilde) (ΔT ₁ ) of the capacitor voltage v _c are estimated and output.

The second observer 24 receives a dead time period ΔT ₂ from the time when the first switching element 14 is turned off to the time when the second switching element 16 is turned on after the time ΔT _{1 has} elapsed. When the second observer 24 receives the input of time ΔT ₂ , either of the observers 40 and 42 depends on the direction of the estimated value i _L (tilde) (ΔT ₁ ) of the reactor current iL input from the first observer 22. Select. When the observer 40 is selected, the time ΔT ₂ at time T in the state equation (formula (2) and formula (3)) when the first switching element 14 is in the on state, and the first observer 22 at v _c (t). estimate v _c of the capacitor voltage v _c (tilde) (ΔT _1), v _b measured value of the supply voltage v _b in (t), a reactor by substituting the measured value of the output current i _m to i _m (t) An estimated value i _L (tilde) (ΔT ₂ ) of the current i _L and an estimated value v _c (tilde) (ΔT ₂ ) of the capacitor voltage vc are estimated and output. When the observer 42 is selected, the time ΔT ₂ at time T of the state equation (formula (5) and formula (6)) when the first switching element 14 is in the OFF state, and the first observer 22 at v _c (t). estimate v _c of the capacitor voltage v _c (tilde) (ΔT _1), v _b measured value of the supply voltage v _b in (t), a reactor by substituting the measured value of the output current i _m to i _m (t) An estimated value i _L (tilde) (ΔT ₂ ) of the current i _L and an estimated value v _c (tilde) (ΔT ₂ ) of the capacitor voltage v _c are estimated and output.

The third observer 26 receives the time ΔT ₃ while the second switching element 16 is on after the dead time ΔT _{2 has} elapsed. The third observer 26 receives an input of time [Delta] T _3, the equation of state when the first switching element 14 is off (Equation (5) and Equation (6)) time T of the [Delta] T _3, v _c (t ) the estimated value v _c of the capacitor voltage v _c in the second observer 24 (tilde) ([Delta] t _2), v _b (measurement value of power supply voltage v _b to t), the output current i _m to i _m (t) Substituting the measured values, the estimated value i _L (tilde) (ΔT ₃ ) of the reactor current i _L and the estimated value v _c (tilde) (ΔT ₃ ) of the capacitor voltage v _c are estimated and output.

The fourth observer 28 receives a dead time period ΔT ₄ from when the second switching element 16 is turned off to when the first switching element 14 is turned on after the time ΔT _{3 has} elapsed. When the fourth observer 28 receives the input of the time ΔT ₄ , any of the observers 40 and 42 depends on the direction of the estimated value i _L (tilde) (ΔT ₃ ) of the reactor current i _L input from the third observer 26. Select. When the observer 40 is selected, time ΔT ₄ at time T in the state equation (formula (2) and formula (3)) when the first switching element 14 is in the on state, and v 1 ( _c ) at the first observer 22. estimate v _c of the capacitor voltage v _c (tilde) (ΔT _3), v _b measured value of the supply voltage v _b in (t), a reactor by substituting the measured value of the output current i _m to i _m (t) The estimated value i _L (tilde) (ΔT ₄ ) of the current i _L and the estimated value v _c (tilde) (ΔT ₄ ) of the capacitor voltage v _c are estimated and output. When the observer 42 is selected, time ΔT ₄ at time T in the state equation (formula (5) and formula (6)) when the first switching element 14 is in the off state, and v 1 ( _c ) at the first observer 22. estimate v _c of the capacitor voltage v _c (tilde) (ΔT _3), v _b measured value of the supply voltage v _b in (t), a reactor by substituting the measured value of the output current i _m to i _m (t) The estimated value i _L (tilde) (ΔT ₄ ) of the current i _L and the estimated value v _c (tilde) (ΔT ₄ ) of the capacitor voltage v _c are estimated and output.

The fifth observer 30, after the dead time period [Delta] T ₄ has elapsed, the first switching element 14 and the second switching element 16 is in the ON state time [Delta] T ₅ until it is in the OFF state is input. The fifth observer 30 receives an input of time [Delta] T _5, T the time [Delta] T ₅ of the state equation with the first switching element 14 is turned on (Equation (2) and Equation (3)), v _c (t ) the estimated value v _c of the capacitor voltage v _c in the fourth observer 28 (tilde) ([Delta] t _4), v _b (measurement value of power supply voltage v _b to t), the output current i _m to i _m (t) Substitute the measured value, and feed back the value obtained by multiplying the estimated value v _c (tilde) (ΔT ₅ ) of the previous capacitor voltage v _c in the previous fifth observer 30 by the observer gains k ₁ and k _2. The estimated value i _L (tilde) (ΔT ₅ ) of the reactor current i _L and the estimated value v _c (tilde) (ΔT ₅ ) of the capacitor voltage v _c are estimated and output.

By such processing, as shown in FIG. 7, the estimated value i _L (tilde) (T) of the reactor current i _L and the estimated value v _c (tilde) (T) of the capacitor voltage v _c at each time are estimated. be able to.

The effect of power conversion device 100 in the present embodiment will be described. Figure 8 shows the time variation of the capacitor voltage v _c and reactor current i _L calculated based on the prior art described in Patent Document 1. FIG. 9 is an enlarged view showing the time change of reactor current i _L in FIG. In FIG. 9, the reactor current estimated value i _L (tilde) is indicated by a thin solid line, and the detected value (actual value) of the reactor current i _L is indicated by a thick solid line. As shown in FIG. 9, there was an error in the absolute value of the detected value (actual value) of the reactor current estimated value i _L (tilde) and the reactor current i _L.

FIG. 10 shows the frequency response of the reactor current i _L obtained based on the prior art described in Patent Document 1. The frequency responsiveness is a result of looking at the current estimation accuracy at the time of evaluating the voltage control followability when the target voltage value is changed with a sine wave. In FIG. 10, the reactor current estimated value i _L (tilde) is indicated by a thin solid line, and the detected value (actually measured value) of the reactor current i _L is indicated by a thick solid line. As shown in FIG. 10, the fluctuation period of the reactor current estimated value i _L (tilde) is close to the fluctuation period of the detected value (actually measured value) of the reactor current i _L , but the reactor current estimated value i _L ( The absolute value of tilde) was offset and did not match the detected value (actual value) of reactor current i _L.

FIG. 11 is an enlarged view showing the time change of reactor current i _L obtained by power conversion device 100 in the present embodiment. In FIG. 11, the reactor current estimated value i _L (tilde) is indicated by a thin solid line, and the detected value (actual value) of the reactor current i _L is indicated by a thick solid line. As shown in FIG. 11, the absolute value of the detected value (actually measured value) of the reactor current estimated value i _L (tilde) and the reactor current i _L is substantially the same.

FIG. 12 shows the frequency response of reactor current i _L obtained by power conversion device 100 in the present embodiment. In FIG. 12, the reactor current estimated value i _L (tilde) is indicated by a thin solid line, and the detected value (actual value) of the reactor current i _L is indicated by a thick solid line. As shown in FIG. 12, the fluctuation period of the reactor current estimated value i _L (tilde) coincides with the variation period of the detection value of the reactor current i _L (measured value), reactor current estimated value i _L (tilde) Also, the absolute value of was substantially the same as the detected value (actual value) of the reactor current i _L without being offset.

  In this embodiment, Equations (1) and (4) are discretized using bilinear transformation. However, the present invention is not limited to this, and the zero-order hold, forward difference, and backward difference are calculated. It may be discretized by use.

For example, when formula (1) is discretized by applying a backward difference, it can be expressed as formula (7). Further, the coefficients A, B, and C can be defined as in Expression (8) with respect to Expression (7).

Further, when Equation (4) is discretized by applying the backward difference, it can be expressed as Equation (9). Further, coefficients A, B, and C can be defined as in Expression (10) with respect to Expression (9).

By applying the state equations obtained by discretizing Equation (1) and Equation (4) using the backward difference in this way to the first observer 22 to the fifth observer 30, similarly, the reactor current estimated value i _L (tilde ) Can be estimated.

The output current calculator in the case where the inverter and the motor to the power conversion device 100 is connected one can calculate the output current i _m by equation (11). In Equation (11), the motor d-axis voltage command v _d , the motor q-axis voltage command v _q , the dead time error d-axis voltage v _dd, and the dead time error q-axis voltage v _qd are used.

  When there are two or more inverters and motors, the motor power may be added to the numerator of Equation (11).

  As described above, according to the embodiment of the present invention, the estimation error of the reactor current can be suppressed by using the observer to which different state equations are applied in the ON state and the OFF state of the first switching element 14. . Further, the estimation error of the reactor current is suppressed by applying the state equation in which the first switching element 14 is in the ON state and the state equation in the OFF state, respectively, when the estimated value of the reactor current of the dead time is positive and negative. can do. Furthermore, the estimated accuracy of the reactor current can be increased by feeding back the estimated value of the capacitor voltage.

<Second Embodiment>
In 1st Embodiment, it was set as the aspect which performs an estimation process using the state equation which does not consider the duty d. The power conversion apparatus 100 according to the second embodiment performs an estimation process using a state equation that takes into account the duty d and the error duty Δd due to the dead time times ΔT ₂ and ΔT ₄ .

  Note that the configuration of the power conversion device 100 in the second embodiment is the same as that of the power conversion device 100 in the first embodiment, and only the difference is applied, so only the differences will be described.

A state equation in consideration of the duty d indicating the ON ratio of the first switching element 14 with respect to the period of the carrier signal is expressed as Expression (12).

If the bilinear transformation is applied to the equation (12) as a one-dimensional observer and discretized, it can be expressed as the equation (13).

Further, the coefficients A, B, and C can be defined as in Expression (14) with respect to Expression (13).

FIG. 13 is an enlarged view showing the time change of reactor current i _L obtained by power conversion device 100 in the present embodiment. In FIG. 13, the reactor current estimated value i _L (tilde) is indicated by a thin solid line, and the detected value (actual value) of the reactor current i _L is indicated by a thick solid line. As shown in FIG. 13, the absolute value of the detected value (actual value) of the reactor current estimated value i _L (tilde) and the reactor current i _L is substantially the same.

FIG. 14 shows the frequency responsiveness of reactor current i _L obtained by power conversion device 100 in the present embodiment. In FIG. 14, the reactor current estimated value i _L (tilde) is indicated by a thin solid line, and the detected value (actually measured value) of the reactor current i _L is indicated by a thick solid line. As shown in FIG. 14, the fluctuation period of the reactor current estimated value i _L (tilde) coincides with the variation period of the detection value of the reactor current i _L (measured value), reactor current estimated value i _L (tilde) Also, the absolute value of was substantially the same as the detected value (actual value) of the reactor current i _L without being offset.

  In the present embodiment, the same dimensional observer is used, but a minimum dimensional observer may be applied. Moreover, although Formula (11) was discretized using bilinear transformation, it is not limited to this, You may discretize using 0th-order hold, a forward difference, and a backward difference.

  As described above, it is possible to further improve the estimation accuracy of the reactor current in the power conversion device 100 by configuring the disturbance observer in which the duty error generated in the dead time is added to the state equation as a disturbance.

  DESCRIPTION OF SYMBOLS 10 DC power supply, 12 Reactor, 14 1st switching element, 16 2nd switching element, 18 capacitor | condenser, 20 Time calculator between switching, 22 1st observer, 24 2nd observer, 26 3rd observer, 28 4th observer, 30 5th observer, 40, 42 observer, 44 changeover switch, 100 power converter, 102 load, 200 observer.

Claims (7)

A reactor connected to a power source;
A first switching element and a second switching element for controlling a current flowing through the reactor;
A capacitor for smoothing the output voltage from the reactor;
A power conversion device for direct current power conversion comprising:
Power converter, characterized in that it comprises an observer that estimates the power supply voltage v _b, the terminal voltage of the capacitor v _c and reactor current i _L flowing through the reactor on the basis of the output current i _m of the power supply. The power conversion device according to claim 1,
The observer includes an on-time of the first switching element and an on-time of the second switching element with respect to a state equation when the first switching element is on and a state equation when the second switching element is on. The power converter according to claim 1, wherein the reactor current i _L is estimated by applying a time and a dead time when the first switching element and the second switching element are simultaneously turned off. The power conversion device according to claim 2,
The observer is configured to determine the on-time of the first switching element, the on-time of the second switching element, and the on-time of the first switching element and the second switching element based on the duty of the on / off state and the triangular wave comparison PWM. A power converter that calculates dead time. The power conversion device according to claim 2 or 3,
The observer applies a state equation when the first switching element is in an on state when the estimated value of the reactor current is positive, and when the estimated value of the reactor current is negative at the dead time time. Applies a state equation when the second switching element is in an ON state. The power conversion device according to claim 2,
The power converter according to claim 1, wherein the observer is a disturbance observer to which a duty error generated during the dead time is added as a disturbance. The power converter according to any one of claims 1 to 5,
The observer, and characterized in that the power supply voltage is sampled at a timing synchronized with the period of the carrier signal v _b, as an input the output current i _m and capacitor voltage v _c, estimates the reactor current i _L for each of the timing Power converter. The power conversion device according to any one of claims 1 to 6,
The reactor current i _L is estimated based on a three-phase voltage command and a three-phase current detection value of an inverter.