JP6993925B2 - Power converter control device - Google Patents

Description

The present invention relates to a control device applied to a power conversion device.

Patent Document 1 discloses a control device having a reactor and a drive switch and applied to a power conversion device that converts an AC voltage into a DC voltage. The control device operates the drive switch by the well-known peak current mode control in order to control the reactor current flowing through the reactor to the command value. Further, the control device reduces the distortion of the AC current by adding the current correction value that changes according to the phase of the AC voltage to the command value.

JP-A-2015-198460

In the correction method of adding the correction value to the command value, the smaller the command value of the reactor current, the larger the ratio of the correction value to the corrected command value. Therefore, if the ratio of the correction amount to the corrected command value becomes excessive, the command value may be overcorrected and the reactor current may flow excessively with respect to the command value.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a control device capable of suppressing overcorrection of a command value of a reactor current in a power conversion device.

In order to solve the above problems, the first invention has a reactor and a drive switch, and is a power conversion device that converts one input voltage of AC voltage and DC voltage into the other voltage and outputs it. Regarding the control device of the power conversion device applied to. The control device includes a current acquisition unit that acquires the reactor current flowing through the reactor, an AC voltage acquisition unit that acquires the AC voltage, a reference waveform indicating the voltage change of the AC voltage, and an amplitude command indicating the amplitude of the reactor current. A command value calculation unit that calculates a command current, which is a command value of the reactor current, based on the integrated value of the values, and a command value calculation unit for correcting the calculated command current based on the acquired AC voltage. A correction value setting unit that sets a correction coefficient, a current control unit that operates the drive switch by peak current mode control in order to control the acquired reactor current to the calculated command current, the reference waveform, and the reference waveform. A correction unit for correcting the command current used in the current control unit is provided by integrating the correction coefficient into any of the values obtained by integrating the amplitude command value into the reference waveform.

When the correction coefficient is integrated into either the reference waveform or the value obtained by integrating the amplitude command value into the reference waveform, the correction amount by the correction coefficient is proportional to the original value to be integrated. Therefore, when the command current is small, it is possible to prevent the correction amount occupying the corrected command current from becoming excessively large. In this respect, in the above configuration, the drive switch is operated by peak current mode control in order to control the acquired reactor current to the command current. At this time, the correction coefficient is integrated into either the reference waveform or the value obtained by integrating the amplitude command value into the reference waveform. In this case, it is possible to suppress the overcorrection of the command current due to the excessive correction amount occupying the command current.

In the second invention, the correction value setting unit sets the correction coefficient based on the acquired AC voltage and the amplitude command value, and the larger the amplitude command value is, the smaller the correction coefficient is. Set.

The larger the amplitude command value, the larger the reactor current flowing through the reactor. Therefore, in order to suppress the excessive flow of the reactor current, it is better to reduce the correction coefficient as the amplitude command value increases. In this respect, in the above configuration, the correction coefficient is set based on the AC voltage and the amplitude command value, and the larger the amplitude command value is, the smaller the correction coefficient is set. In this case, it is possible to suppress the excessive flow of the reactor current.

In the third invention, a determination unit for determining whether or not the load of the power conversion device is larger than a predetermined value is provided, and the correction unit is such that the load of the power conversion device is equal to or less than the predetermined value by the determination unit. When it is determined to be present, the command current used in the current control unit is corrected by integrating the correction coefficient into either the reference waveform or the value obtained by integrating the amplitude command value into the reference waveform. When the determination unit determines that the load of the power conversion device is larger than the predetermined value, the current control unit adds a correction value to the value obtained by integrating the amplitude command value into the reference waveform. The command current used in the above is corrected.

When the power conversion device is driven with a high load, higher responsiveness to a command current is required as compared with the case where the power converter is driven with a low load. Here, when the correction value is integrated into the command current, the processing load of the control device is higher than when the correction coefficient is added, so that the responsiveness when calculating the command value is low. In this respect, in the above configuration, when it is determined that the load of the power conversion device is equal to or less than a predetermined value, the correction coefficient is integrated into either the reference waveform or the value obtained by integrating the amplitude command value into the reference waveform. On the other hand, when it is determined that the load of the power conversion device is larger than the predetermined value, the correction value is added to the value obtained by integrating the amplitude command value with the reference waveform. In this case, it is possible to suppress overcorrection for the command current and not impair the responsiveness to the command current at the time of high load.

The block diagram of the power conversion apparatus which concerns on 1st Embodiment. A functional block diagram illustrating the function of the control device. The figure which shows the transition of the average value of an AC voltage, a command current before correction, and a reactor current. The figure explaining the relationship between the AC voltage and the deviation width. The figure explaining the divergence width. The flowchart which shows the operation procedure of the switch using the peak current mode control. The block diagram of the power conversion apparatus which concerns on 2nd Embodiment. Functional block diagram of the control device. The figure explaining the relationship between the AC voltage and the deviation width. The functional block diagram of the control apparatus which concerns on 3rd Embodiment.

<First Embodiment>
An aspect of the control device of the power conversion device according to the present embodiment will be described with reference to the drawings. The power conversion device according to the present embodiment converts an AC voltage supplied from an AC power supply into a DC voltage.

As shown in FIG. 1, the power converter 100 includes an AC / DC converter 10. The AC / DC converter 10 is connected to the AC power supply 200 via the first AC terminal TA1 and the second AC terminal TA2, and is connected to a device (not shown) via the first DC terminal TD1 and the second DC terminal TD2. ing. The AC power supply 200 is, for example, a commercial power supply. The device includes, for example, a DC power source such as a battery and at least one of a DC / DC converter.

The AC / DC converter 10 includes a full bridge circuit 12, a half bridge circuit 15, a reactor 13, a capacitor 16, and first to sixth wirings LP1 to LP6.

The full bridge circuit 12 includes first to fourth diodes D1 to D4. The anode of the first diode D1 and the cathode of the second diode D2 are connected, and the anode of the third diode D3 and the cathode of the fourth diode D4 are connected. Each cathode of the first and third diodes D1 and D3 is connected to the first end of the third wiring LP3, and each anode of the second and fourth diodes D2 and D4 is connected to the first end of the fourth wiring LP4. There is.

In the full bridge circuit 12, the first connection point K1 between the first diode D1 and the second diode D2 is connected to the first end of the fifth wiring LP5, and the second end of the fifth wiring LP5 is the first alternating current. It is connected to the terminal TA1. The second connection point K2 between the third diode D3 and the fourth diode D4 is connected to the first end of the sixth wiring LP6, and the second end of the sixth wiring LP6 is connected to the second AC terminal TA2. There is.

The half-bridge circuit 15 includes a fifth diode D5 and a switch SW. The switch SW is a voltage-driven switch, and is an n-channel MOSFET in this embodiment. The anode of the fifth diode D5 and the drain of the switch SW are connected. The cathode of the fifth diode D5 is connected to the first end of the first wiring LP1, and the second end of the first wiring LP1 is connected to the first DC terminal TD1. The source of the switch SW is connected to the first end of the second wiring LP2, and the second end of the second wiring LP2 is connected to the second DC terminal TD2. The switch SW includes a parasitic diode connected in antiparallel.

The third connection point K3 between the fifth diode D5 and the switch SW is connected to the second end of the third wiring LP3. A reactor 13 is provided on the third wiring LP3. Further, the source of the switch SW is connected to the second end of the fourth wiring LP4.

The capacitor 16 is connected between the first wiring LP1 and the second wiring LP2.

The power conversion device 100 includes a first voltage sensor 31, a current sensor 32, and a second voltage sensor 33. The first voltage sensor 31 is connected between the first wiring LP1 and the second wiring LP2, and detects the voltage between the terminals of the capacitor 16 as the DC voltage Vdc. In the present embodiment, the sign of the DC voltage Vdc is defined as positive when the potential on the first wiring LP1 side is higher than the potential on the second wiring LP2 side among both ends of the capacitor 16. The current sensor 32 is provided in the fourth wiring LP4, and detects the current flowing through the reactor 13 as the reactor current ILr. The second voltage sensor 33 is connected between the fifth wiring LP5 and the sixth wiring LP6, and detects the voltage of the AC power supply 200 as the AC voltage Vac.

The power conversion device 100 includes a control device 30. Each function provided by the control device 30 can be provided, for example, by software recorded in a substantive memory device and a computer, hardware, or a combination thereof that executes the software.

FIG. 2 is a functional block diagram illustrating the functions of the control device 30. The control device 30 operates the switch SW to an off state (open state) or an on state (closed state) by a well-known peak current mode control. The control device 30 includes a waveform generation unit 40, a correction unit 41, a multiplier 42, an absolute value calculation unit 43, a correction value setting unit 44, and a current control unit 50. In the present embodiment, the waveform generation unit 40, the correction unit 41, the multiplier 42, and the absolute value calculation unit 43 correspond to the command value calculation unit.

The waveform generation unit 40 generates a reference waveform sinωt indicating a change in the AC power supply 200. The reference waveform is a value indicating a voltage change in a half cycle (T / 2) of the AC power supply 200. For example, the waveform generation unit 40 detects the point where the AC voltage Vac detected by the second voltage sensor 33 becomes 0 as the zero cross timing, and sets the period during which the AC voltage Vac changes from the zero cross timing to the next zero cross timing. , Set as a half cycle (T / 2) of the AC power supply 200. Then, the waveform generation unit 40 calculates the angular velocity ω (= 2π × (1 / T)) of the AC power supply 200 from the period T. The waveform generation unit 40 calculates the reference waveform sinωt having the same phase as the AC voltage Vac by setting the angular velocity of the sinusoidal signal having an amplitude of 1 to the calculated angular velocity ω.

The correction unit 41 integrates the correction coefficient k set by the correction value setting unit 44 into the reference waveform generated by the waveform generation unit 40. The correction coefficient k is a correction value for suppressing the distortion of the alternating current Iac. The correction coefficient k will be described later.

The multiplier 42 integrates the reference waveform sinωt in which the correction coefficient k is integrated and the amplitude command value Ia *. The amplitude command value Ia * is a command value that determines the amplitude of the reactor current ILr, and is determined based on, for example, a command value of the DC voltage Vdc that is the output voltage.

The absolute value calculation unit 43 calculates the absolute value | k × Ia * × sinωt | of the output value from the multiplier 42 as the command current IL *.

The current control unit 50 outputs a gate signal GS for operating the switch SW based on the reactor current ILr detected by the current sensor 32 and the command current IL *. In the present embodiment, the current control unit 50 outputs the gate signal GS by well-known peak current mode control.

The current control unit 50 includes a DA converter 351, a comparator 352, an adder 353, an RS flip-flop 357, and a slope compensation unit 51. The command current IL * is converted from a digital value to an analog value by the DA converter 351. The command current IL * converted to an analog value is input to the inverting input terminal of the comparator 352. The adder 353 adds the reactor current ILr and the slope compensation signal Slope set by the slope compensation unit 51. The output from the adder 353 is input to the non-inverting input terminal of the comparator 352. The slope compensation signal Slope suppresses oscillation due to fluctuations in the current flowing through the reactor 13.

The comparator 352 compares the command current IL * with the reactor current ILr after slope compensation, and outputs a low-level signal to the R terminal of the RS flip-flop 357 during a period in which the reactor current ILr after slope compensation is smaller than the command current IL *. Enter in. Further, the comparator 352 inputs a high level signal to the R terminal of the RS flip-flop 357 during a period in which the reactor current ILr after slope compensation is larger than the command current IL *. Further, a clock signal is input to the S terminal of the RS flip-flop 357. The period from when the clock signal is switched to the high level until the clock signal is switched to the next high level is one switching cycle Tsw of the switch SW.

The Q terminal of the RS flip-flop 357 is connected to the gate of the switch SW. The signal output from the Q terminal to the gate of the switch SW is the gate signal GS.

Next, the operation of the power conversion device 100 will be described. FIG. 3A shows the transition of the AC voltage Vac, and FIG. 3B shows the pre-correction command current ILp * (= | Ia *) which is the absolute value of the multiplication value of the amplitude command value Ia * and the reference waveform. The transition of × sinωt |) is shown. FIG. 3C shows the transition of the average value Iave of the reactor current ILr. Further, in FIG. 3A, t1, t3, t5 indicate the zero cross timing of the AC voltage Vac, and t2, t4 indicate the peak timing at which the AC voltage Vac has positive and negative peak values.

By the peak current mode control carried out by the current control unit 50, the gate signal GS becomes a high level, so that the switch SW is turned on (closed state), and a closed circuit including the reactor 13 and the switch SW is formed. Further, a current flows through the reactor 13 in the closed circuit, and magnetic energy is stored in the reactor 13. When the gate signal GS becomes low level, the switch SW is turned off (open state), and the magnetic energy stored in the reactor 13 causes a current to flow through the fifth diode D5 to the first DC terminal TD1.

As shown in FIGS. 3A and 3B, the pre-correction command current ILp * changes so that a positive half wave of a sine wave is repeated in synchronization with a voltage change of the AC voltage Vac. Further, as shown in FIG. 3C, in the distortion-free reactor current ILr, the mean value Iave is the same as the pre-correction command current ILp *, and a positive half wave of a sine wave is generated in synchronization with the change of the AC voltage Vac. It changes to be repeated.

On the other hand, in reality, the reactor current ILr may be distorted, and in this case, the average value Iave may not be the waveform shown in FIG. 3 (c). In the peak current mode control, the AC current Iac is distorted because the reactor current ILr does not become an appropriate value.

Specifically, when the AC voltage Vac is converted to the DC voltage Vdc, as shown in FIGS. 4 (a) and 4 (b), the average value Iave of the reactor current ILr in which distortion occurs and the pre-correction command current ILp *. The deviation width Δi indicating the difference from and is the largest value in the vicinity of the zero cross timing (t1, t3, t5). Further, the deviation width Δi becomes the smallest value near the peak timing (t2, t4) of the AC voltage Vac. Therefore, the correction value setting unit 44 increases the reactor current ILr near the zero cross timing by setting the correction coefficient k according to the AC voltage Vac.

Here, unlike the configuration in which the correction coefficient k is integrated into the pre-correction command current ILp *, when the correction value is added to the pre-correction command current ILp *, the smaller the command current IL *, the more the correction for this command current IL *. The ratio of values increases. Therefore, if the correction value occupying the command current IL * becomes excessive, there is a concern that the reactor current ILr may flow excessively with respect to an appropriate value for suppressing the distortion of the AC current Iac. On the other hand, when the command current IL * is calculated by integrating the correction coefficient k with the pre-correction command current ILp *, the ratio of the correction amount by the correction coefficient k to the command current IL * when the command current IL * is large is , The ratio is the same as the ratio of the correction amount to the command current IL * when the command current IL * is small. Therefore, according to the present embodiment in which the correction coefficient k is used, even when the command current IL * is small, it is possible to suppress the correction amount occupying the command current IL * from becoming excessively large. Therefore, the control device 30 includes a correction value setting unit 44 for setting the correction coefficient k and a correction unit 41.

In the present embodiment, the correction value setting unit 44 sets the correction coefficient k so that the amount of increase in the duty ratio at the zero cross timing is larger than that at other timings. Here, the duty ratio indicates the ratio (= Ton / Tsw) of the on-operation period Ton to one switching cycle Tsw. Specifically, one minimum value is taken in each of the periods P1 and P2 in which the AC voltage Vac is positive and negative, and the minimum value in the first period P1 in which the AC voltage is positive and the second period P2 in which the negative is negative. The correction coefficient k is set so as to take one maximum value between the minimum value and the minimum value in.

Further, the larger the amplitude command value Ia * is, the larger the reactor current ILr is. Therefore, in order to suppress the excessive flow of the reactor current ILr by the correction, the larger the amplitude command value Ia * is, the smaller the correction coefficient k is. It is better to do it. Therefore, in the present embodiment, the correction value setting unit 44 sets the correction coefficient k to a smaller value as the amplitude command value Ia * becomes larger.

In the present embodiment, the control device 30 includes a storage unit such as a memory, and the storage unit includes an AC voltage Vac, a DC voltage Vdc, a reference waveform sinωt, an amplitude command value Ia *, and a correction coefficient k. A correction value map showing the relationship is stored. Therefore, the correction value setting unit 44 can set the correction coefficient k according to each value Vac, Vdc, sinωt, Ia * by referring to the correction value map.

Next, a method of creating a correction value map showing the correspondence between the amplitude command value Ia * and the correction coefficient k will be described with reference to FIG.

FIG. 5 is a diagram illustrating a deviation width Δi. In the present embodiment, the deviation width Δi is defined as the difference between the average value Iave of the reactor current ILr and the command current IL *. Therefore, assuming that the maximum increase in the reactor current ILr in one switching cycle Tsw is ΔIL, the deviation width Δi is the difference between the average value Iave and the maximum increase ΔIL (= ΔIL / 2), and the maximum increase in the slope compensation signal Slope. It is the value obtained by adding the minute ΔSlope. Further, in the present embodiment, the deviation width Δi is calculated by the following equation (1) using the slope mb when the reactor current ILr increases and the slope amount ms. In the following formula (1), D is a duty ratio.

Δi = mb × D × Tsw / 2 + ms × D × Tsw… (1)
The slope (rising speed of reactor current ILr) mb when the reactor current ILr increases has a relationship of "mb = Vac / L", and by substituting this relationship into the above equation (1), the deviation width Δi can be obtained. It is calculated by the following formula (2).

電力変換装置１００が交流電圧を直流電圧に変換する場合、デューティ比Ｄは下記式（３）により算出される。

When the power conversion device 100 converts an AC voltage into a DC voltage, the duty ratio D is calculated by the following equation (3).

ここで、補正前指令電流ＩＬｐ＊（＝｜Ｉａ＊×ｓｉｎωｔ｜）が乖離幅Δｉに応じた値となることで、交流電流Ｉａｃの歪みが抑制されるため、乖離幅Δｉ、補正係数ｋ、及び補正前指令電流ＩＬｐ＊は、下記式（４）の関係性がある。
Δｉ＝ｋ×ＩＬｐ＊ … （４）
そのため、補正係数ｋは、上記式（４）の乖離幅Δｉに上記（２）式を代入し、代入後の式を補正係数ｋの式として展開した下記式（５）により算出される。

Here, since the pre-correction command current ILp * (= | Ia * × sinωt |) becomes a value corresponding to the deviation width Δi, the distortion of the AC current Iac is suppressed, so that the deviation width Δi, the correction coefficient k, And the pre-correction command current ILp * are related to the following equation (4).
Δi = k × ILp *… (4)
Therefore, the correction coefficient k is calculated by the following equation (5) in which the equation (2) is substituted into the deviation width Δi of the equation (4) and the substituted equation is expanded as the equation of the correction coefficient k.

本実施形態では、上記式（３），（５）を用いて、交流電圧Ｖａｃと、補正前指令電流ＩＬｐ＊とに応じた補正係数ｋを算出する。ここで、「ＩＬｐ＊＝０」となる場合、補正係数ｋが発散する。このため、本実施形態では、「ＩＬｐ＊＝０」とならないような補正前指令電流ＩＬｐ＊が設定される。例えば、非常に小さい値を規定値ε（＞０）とする場合、正弦波状に変化するＩＬｐ＊が規定値ε以下になる場合、「ＩＬｐ＊＝ε」すればよい。そして、算出した補正係数ｋを、振幅指令値Ｉａ＊と交流電圧Ｖａｃとに対応付けることにより補正値マップを作成する。

In this embodiment, the correction coefficient k corresponding to the AC voltage Vac and the pre-correction command current ILp * is calculated using the above equations (3) and (5). Here, when "ILp * = 0", the correction coefficient k diverges. Therefore, in the present embodiment, the pre-correction command current ILp * is set so as not to be “ILp * = 0”. For example, when a very small value is set to the specified value ε (> 0), and the ILp * changing in a sine and cosine shape is equal to or less than the specified value ε, “ILp * = ε” may be used. Then, the correction value map is created by associating the calculated correction coefficient k with the amplitude command value Ia * and the AC voltage Vac.

Next, the operation procedure of the switch SW using the peak current mode control will be described with reference to FIG. The process shown in FIG. 6 is repeatedly performed by the control device 30 at a predetermined cycle.

In step S10, the reactor current ILr detected by the current sensor 32 is acquired. Step S10 corresponds to the current acquisition unit. In step S11, the AC voltage Vac detected by the second voltage sensor 33 is acquired. Step S11 corresponds to the AC voltage acquisition unit.

In step S12, the correction coefficient k is set based on the AC voltage Vac and the amplitude command value Ia *. In step S13, the correction coefficient k is integrated into the reference waveform sinωt.

In step S14, the amplitude command value Ia * is integrated with the reference waveform sinωt in which the correction coefficient k is integrated in step S13, and the absolute value of the integrated value is calculated as the command current IL *. Steps S13 and S14 correspond to the command value calculation unit.

In step S15, as described with reference to FIG. 2, the gate signal GS when the peak current mode control is performed based on the command current IL * is output. As a result, the reactor current ILr is controlled to the command current IL * set in step S14. As a result, the reactor current ILr in which the distortion of the alternating current Iac is suppressed flows through the reactor 13. When the process of step S15 is completed, the process of FIG. 6 is temporarily terminated.

In the present embodiment described above, the following effects are obtained.

The control device 30 operates the switch SW by peak current mode control in order to control the reactor current ILr to the command current IL *. At this time, the command current IL * is calculated based on the value obtained by integrating the correction coefficient k on the reference waveform sinωt. In this case, it is possible to suppress the overcorrection of the command current IL * due to the excessive correction amount occupying the command current IL *.

The control device 30 sets the correction coefficient k based on the AC voltage Vac and the amplitude command value Ia *, and sets the correction coefficient k to a smaller value as the amplitude command value Ia * becomes larger. In this case, it is possible to suppress the excessive flow of the reactor current ILr.

<Modified example of the first embodiment>
The control device 30 may calculate the command current IL * by integrating the amplitude command value Ia * into the reference waveform sinωt and then integrating the correction coefficient k into the integrated value. In this case, the correction unit 41 may be provided between the absolute value calculation unit 43 and the current control unit 50.

<Second Embodiment>
In the second embodiment, a configuration different from that of the first embodiment will be mainly described. The configurations with the same reference numerals as those of the first embodiment show the same configurations, and the description thereof will not be repeated.

The power conversion device 100 of the present embodiment converts a DC voltage into an AC voltage. The power converter 100 shown in FIG. 7 includes a DC / AC converter 80. The DC / AC converter 80 includes a capacitor 16, a half-bridge circuit 73, a reactor 13, a full-bridge circuit 74, and first to sixth wirings LP1 to LP6.

The half-bridge circuit 73 includes a first switch SW11 and a second switch SW12. The first and second switches SW11 and SW12 are voltage-driven switches, and in this embodiment, they are n-channel MOSFETs. The source of the first switch SW11 and the drain of the second switch SW12 are connected. The drain of the first switch SW11 is connected to the first wiring LP1, and the source of the second switch SW12 is connected to the second wiring LP2. Each of the first and second switches SW11 and SW12 includes a parasitic diode connected in anti-parallel connection. In this embodiment, the first switch SW11 corresponds to the drive switch.

The first connection point K21 of the first and second switches SW11 and SW12 is connected to the first end of the third wiring LP3. A reactor 13 is provided in a part of the third wiring LP3. Further, the source of the second switch SW12 is connected to the first end of the fourth wiring LP4. The second end of each of the third and fourth wirings LP3 and LP4 is connected to the full bridge circuit 74.

The full bridge circuit 74 includes third to sixth switches SW13 to SW16. The third to sixth switches SW13 to SW16 are voltage-driven switches, and are n-channel MOSFETs in the present embodiment. The source of the third switch SW13 and the drain of the fourth switch SW14 are connected. The source of the fifth switch SW15 and the drain of the sixth switch SW16 are connected. The drains of the third and fifth switches SW13 and SW15 are connected to the third wiring LP3, and the sources of the fourth and sixth switches SW14 and SW16 are connected to the fourth wiring LP4.

The second connection point K22 between the third switch SW13 and the fourth switch SW14 is connected to the first end of the fifth wiring LP5, and the second end of the fifth wiring LP5 is connected to the first AC terminal TA1. There is. The third connection point K23 between the fifth switch SW15 and the sixth switch SW16 is connected to the first end of the sixth wiring LP6, and the second end of the sixth wiring LP6 is connected to the second AC terminal TA2. There is.

FIG. 8 is a functional block diagram illustrating the function of the control device 30 according to the present embodiment. The control device 30 operates the first and second switches SW11 and SW12 in an off state (open state) or an on state (closed state) by controlling the peak current mode.

The current control unit 150 outputs a first gate signal GS11 for operating the first switch SW11 and a second gate signal GS12 for operating the second switch SW12 based on the reactor current ILr and the command current IL *. The current control unit 150 is connected to the gate of the first switch SW11 and outputs the first gate signal GS11. Further, the current control unit 150 is connected to the gate of the second switch SW12 via the inverting device 162, and outputs the second gate signal GS12 via the inverting device 162.

The switching unit 160 includes a polarity determination unit 161 and reversers 162 and 163. The polarity determination unit 161 sets the output signal to a low level when the AC voltage Vac is determined to be positive, and sets the output signal to a high level when the AC voltage Vac is determined to be negative.

The polarity determination unit 161 is connected to each gate of the third and sixth switches SW13 and SW16, and outputs the third and sixth gate signals GS13 and GS16 for operating the third and sixth switches SW13 and SW16. Further, the polarity determination unit 161 is connected to each gate of the fourth and fifth switches SW14 and SW15 via the reversing device 163, and operates the fourth and fifth switches SW14 and SW15 via the reversing device 163. The fourth and fifth gate signals GS14 and GS15 are output. The fourth and fifth gate signals GS14 and GS15 are values obtained by inverting the third and sixth gate signals GS13 and GS16.

Next, the operation of the power conversion device 100 according to the present embodiment will be described with reference to FIG. FIG. 9A shows the transition of the AC voltage Vac, and FIG. 9B shows the transition of the deviation width Δi. Further, in FIG. 9A, t31, t33, and t35 indicate the zero cross timing of the AC voltage Vac, and t32 and t34 indicate the peak timing at which the AC voltage Vac becomes a positive and negative peak value.

In the first period P1 in which the AC voltage Vac becomes positive, the fourth and fifth gate signals GS14 and GS15 become high levels, so that the fourth and fifth switches SW14 and SW15 are turned on (closed). .. When the 3rd and 6th gate signals GS13 and GS16 become low level, the 3rd and 6th switches SW13 and SW16 are turned off (open state). Therefore, due to the peak current mode control carried out in the first period P1, the first gate signal GS11 becomes a high level and the second gate signal GS12 becomes a low level, so that the fourth and fifth switches SW14, SW15, and the reactor A closed circuit including 13 and the second switch SW12 is formed.

In the second period P2 in which the AC voltage Vac becomes a negative electrode, the fourth and fifth gate signals GS14 and GS15 become low levels, so that the fourth and fifth switches SW14 and SW15 are turned off (open state). .. Further, when the 3rd and 6th gate signals GS13 and GS16 become high level, the 3rd and 6th switches SW13 and SW16 are turned on (closed state). Therefore, in the second period P2, the current control unit 150 causes the first gate signal GS11 to be at a high level and the second gate signal GS12 to be at a low level, so that the third and sixth switches SW13, SW16, and the reactor 13, And a closed circuit including the second switch SW12 is formed.

In the first and second periods P1 and P2, the deviation width Δi indicating the difference between the average value Iave of the reactor current ILr with distortion and the pre-correction command current ILp * is the largest near the zero cross timing (t31, t33, t35). It will be a small value. Further, the deviation width Δi becomes the largest value in the vicinity of the peak timing (t32, t34) of the AC voltage Vac.

In the present embodiment, the correction value setting unit 44 takes one maximum value in each of the first and second periods P1 and P2 in which the AC voltage Vac becomes positive and negative, and sets the maximum value in the first period P1. The correction coefficient k is set so as to take one minimum value between the maximum value and the maximum value in the second period P2. Further, the correction value setting unit 44 sets the correction coefficient k to a smaller value as the amplitude command value Ia * becomes larger.

Also in this embodiment, the control device 30 stores a correction value map showing the relationship between the AC voltage Vac, the amplitude command value Ia *, and the correction coefficient k in the storage unit. Therefore, the correction value setting unit 44 can set the correction coefficient k according to the amplitude command value Ia * and the AC voltage Vac by referring to this correction value map.

Next, in the present embodiment, a method of creating a correction value map showing the correspondence between the correction coefficient k and the AC voltage Vac will be described.

The slope mb when the reactor current ILr increases has a relationship of "mb = (Vdc- | Vac |) / L". Therefore, by substituting this relationship into the above equation (1), the deviation width Δi when converting the DC voltage Vdc to the AC voltage Vac is calculated by the following equation (6).

ＤＣ・ＡＣ変換器８０が直流電圧を交流電圧に変換する場合、デューティ比Ｄは、下記式（７）により算出される。

When the DC / AC converter 80 converts a DC voltage into an AC voltage, the duty ratio D is calculated by the following equation (7).

補正係数ｋは、上記式（４）の乖離幅Δｉに上記式（６）を代入し、代入後の式を補正係数ｋの式として展開した下記式（８）により算出される。

The correction coefficient k is calculated by the following equation (8) in which the above equation (6) is substituted into the deviation width Δi of the above equation (4) and the substituted equation is expanded as the equation of the correction coefficient k.

本実施形態では、上記式（７），（８）を用いて、交流電圧Ｖａｃと、直流電圧Ｖｄｃと、補正前指令電流ＩＬｐ＊とに応じた補正係数ｋを算出する。そして、算出した補正係数ｋを、交流電圧Ｖａｃに対応付けることにより補正値マップを作成する。

In this embodiment, the correction coefficient k corresponding to the AC voltage Vac, the DC voltage Vdc, and the pre-correction command current ILp * is calculated using the above equations (7) and (8). Then, a correction value map is created by associating the calculated correction coefficient k with the AC voltage Vac.

In the present embodiment described above, the same effect as that of the first embodiment can be obtained even when the DC voltage is converted into the AC voltage.

<Third Embodiment>
In the third embodiment, a configuration different from that of the first embodiment will be mainly described. The configurations with the same reference numerals as those of the first embodiment show the same configurations, and the description thereof will not be repeated.

When the power conversion device 100 is driven with a high load, it is higher than the case where the power converter 100 is driven with a low load with respect to the correction of the pre-correction command current ILp * from the viewpoint of preventing excessive flow of the reactor current ILr. Responsiveness may be required. Here, when the correction coefficient k is integrated into the pre-correction command current ILp *, the processing load of the control device 30 is higher than when the correction value is added to the pre-correction command current ILp *. The responsiveness is low.

In the present embodiment, when the load of the power conversion device 100 is equal to or less than a predetermined value, the command current IL * is calculated by integrating the correction coefficient k into the pre-correction command current ILp *. On the other hand, when the load of the power conversion device 100 is larger than the predetermined value, the command current IL * is calculated by adding the correction value Ic to the pre-correction command current ILp *.

The functional block diagram of the control device 30 according to this embodiment will be described with reference to FIG. In the present embodiment, the correction unit 140 includes a load determination unit 141, a first correction unit 142, and a second correction unit 143.

The load determination unit 141 determines the load of the power conversion device 100 based on the amplitude command value Ia *, and based on the determination result, the pre-correction command current ILp * (= | Ia) output from the absolute value calculation unit 43. * × sinωt |) is output to either the first correction unit 142 or the second correction unit 143. Specifically, when the load determination unit 141 determines that the amplitude command value Ia * is equal to or less than the load determination value THA, the load determination unit 141 outputs the pre-correction command current ILp * to the first correction unit 142. On the other hand, when the load determination unit 141 determines that the amplitude command value Ia * is larger than the load determination value THA, the load determination unit 141 outputs the pre-correction command current ILp * to the second correction unit 143.

The first correction unit 142 integrates the correction coefficient k into the pre-correction command current ILp *. The second correction unit 143 adds the correction value Ic to the pre-correction command current ILp *. Therefore, in the present embodiment, at the time of high load, the value obtained by adding the correction value Ic to the pre-correction command current ILp * is the command current IL *.

In the present embodiment, the correction value setting unit 44 takes one minimum value in each of the periods P1 and P2 in which the AC voltage Vac becomes positive and negative, and in the period of positive and negative. The correction value Ic is set so as to take one maximum value between the minimum value and the minimum value of.

In the present embodiment, the deviation width Δi corresponding to the AC voltage Vac is calculated as the correction value Ic by using the above equations (2) and (3). Then, a correction value map is created by associating the calculated correction value Ic with the AC voltage Vac.

In the present embodiment described above, when the control device 30 determines that the amplitude command value Ia * is equal to or less than the load determination value THA, the control device 30 integrates the correction coefficient k into the pre-correction command current ILp * to obtain the pre-correction command. Calculate the current ILp *. On the other hand, when it is determined that the amplitude command value Ia * is larger than the load determination value THA, the pre-correction command current ILp * is calculated by adding the correction value Ic to the pre-correction command current ILp *. In this case, it is possible to suppress overcorrection with respect to the pre-correction command current ILp * and not impair the responsiveness required at the time of correction under a high load.

<Modified example of the third embodiment>
When the power conversion device 100 converts a DC voltage into an AC voltage, the correction value Ic may be calculated as follows. Specifically, using the above equations (6) and (7), the deviation width Δi corresponding to the AC voltage Vac is calculated as the correction value Ic. Then, a correction value map is created by associating the calculated correction value Ic with the AC voltage Vac.

The load of the power conversion device 100 may be determined by the reactor current ILr instead of the determination based on the amplitude command value Ia *.

<Other embodiments>
-In each embodiment, the case where the power factor is 1 has been described as an example. Instead of this, the present embodiment can be applied even when the power factor is less than 1. In this case, the waveform generation unit 40 may generate a reference waveform (= sin (ωt + α)) whose phase is shifted by a predetermined amount α from the AC voltage Vac according to the power factor.

The control device 30 sets the correction coefficient k based on the AC voltage Vac, the DC voltage Vdc, the reference waveform sinωt, and the amplitude command value Ia *, instead of setting the correction coefficient k by referring to the correction value map. It may be calculated each time. In this case, the calculation cycle of the correction coefficient k may be set so that the reference waveform sinωt does not become 0.

The control device 30 includes a storage unit such as a memory, and the storage unit may store a value obtained by integrating the correction coefficient into the reference waveform.

-For example, when the amplitude command value Ia * is set to a fixed value, the correction coefficient k may be set based only on the AC voltage Vac among the amplitude command value Ia * and the AC voltage Vac.

The power conversion device 100 may be a device that performs bidirectional power conversion between an AC voltage and a DC voltage.

13 ... Reactor, 30 ... Control device, 40 ... Waveform generator, 41 ... Correction unit, 42 ... Multiplier, 43 ... Absolute value calculation unit, 44 ... Correction value setting unit, 50 ... Current control unit, 100 ... Power conversion device , SW ... switch.

Claims (3)

It has a reactor (13) and a drive switch (SW to SW16), and is applied to a power conversion device (100) that converts one of the input voltages of AC voltage and DC voltage into the other voltage and outputs it. It is a control device (30) of the power conversion device to be operated.
A current acquisition unit that acquires the reactor current flowing through the reactor,
The AC voltage acquisition unit that acquires the AC voltage and
A command value calculation unit (40,) that calculates a command current, which is a command value of the reactor current, based on a value obtained by integrating a reference waveform indicating a voltage change of the AC voltage and an amplitude command value indicating the amplitude of the reactor current. 42,43) and
A correction value setting unit (44) for setting a correction coefficient for correcting the calculated command current based on the acquired AC voltage, and a correction value setting unit (44).
A current control unit (50, 150) that operates the drive switch by peak current mode control in order to control the acquired reactor current to the calculated command current.
A correction unit (41, 140) for correcting the command current used in the current control unit by integrating the correction coefficient into either the reference waveform or the value obtained by integrating the amplitude command value into the reference waveform. A control device for the power conversion device provided. The correction value setting unit sets the correction coefficient based on the acquired AC voltage and the amplitude command value, and the larger the amplitude command value is, the smaller the correction coefficient is set in claim 1. The control device for the power converter described. A determination unit (141) for determining whether or not the load of the power conversion device is larger than a predetermined value is provided.
The correction unit
When the determination unit determines that the load of the power conversion device is equal to or less than the predetermined value, the correction coefficient is integrated into either the reference waveform or the value obtained by integrating the amplitude command value into the reference waveform. By doing so, the command current used in the current control unit is corrected.
When the determination unit determines that the load of the power conversion device is larger than the predetermined value, the current control unit adds a correction value to the value obtained by integrating the amplitude command value into the reference waveform. The control device for a power conversion device according to claim 1 or 2, which corrects the command current used.

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