JP2014217210A - Control device for variable inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the control device of a variable inductor capable of avoiding the resonance of first and second LC filters 31 and 41 for auxiliary machine due to the voltage fluctuation of an electric path connecting a high voltage battery 10 to an invertor 20 for main machine.SOLUTION: A first LC filter 31 for auxiliary machine includes a first capacitor 35 and a first variable inductor 36. The first variable inductor 36 includes a core and an auxiliary coil wound around the core. When it is determined that currents flowing through the first capacitor 35 configuring the first LC filter 31 for auxiliary machine exceed an allowable upper limit value, a conductor state to the auxiliary coil is operated such that the resonance frequency of the first LC filter 31 for auxiliary machine is isolated from a voltage fluctuation frequency. Also, the second LC filter 41 for auxiliary machine is processed in the same way.

Description

  The present invention is a variable that is applied to a power conversion system that includes an LC filter that is interposed between each of a plurality of power conversion circuits and a DC power supply and is provided corresponding to each of the plurality of power conversion circuits. The present invention relates to an inductor control device.

  Conventionally, as can be seen, for example, in Patent Document 1 below, a power conversion system including a plurality of power conversion circuits (inverters) connected in parallel to a converter as a DC power supply is known.

JP 2001-37239 A

  By the way, the present inventor, as a power conversion system, is a system including an LC filter interposed between each of a plurality of power conversion circuits and a DC power source and provided corresponding to each of the plurality of power conversion circuits. Considered the adoption of Here, the reason why the LC filter is provided is to reduce the ripple of the input voltage of the power conversion circuit. Here, the ripple of the input voltage is generated by the mechanism described below.

  Harmonic current flows through an electrical path connecting the DC power supply and the power conversion circuit due to driving of at least one of the plurality of power conversion circuits. When a harmonic current flows, a voltage fluctuation occurs in the electric path, thereby causing a ripple of the input voltage.

  Here, when the frequency of the voltage fluctuation becomes close to the resonance frequency of the LC filter, the current flowing through the LC filter increases due to the resonance of the LC filter. If the current flowing through the LC filter increases, the reliability of LC filter components such as capacitors may be reduced. In this case, the ripple reduction effect of the input voltage of the power conversion circuit by the LC filter is greatly reduced, and the reliability of the power conversion circuit may be reduced.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a variable inductor capable of avoiding LC filter resonance caused by voltage fluctuations in an electrical path connecting a DC power supply and a power conversion circuit. It is to provide a control device.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a plurality of power conversion circuits that are connected in parallel to the DC power supply (10) and convert the input voltage to a predetermined value by turning on and off the switching element (S ¥ #). (20, 30, 40) and an LC filter (21, 30) provided between each of the plurality of power conversion circuits and the DC power source and provided corresponding to each of the plurality of power conversion circuits. 31, 41). On the premise of such a configuration, the LC filter (31, 41) connected to a part of the plurality of power conversion circuits (30, 40) includes a capacitor (35). , 45) and variable inductors (36, 46; 50), and the variable inductors are magnetic resistance variable means (36b; 36h; 36h, 36i; 50c, 50d), and a resonance determination means for determining whether or not the LC filter having the variable inductor resonates, and the DC power supply and the power on condition that the resonance determination means has determined that the resonance occurs. The resonance frequency of the LC filter having the variable inductor is separated from the voltage fluctuation frequency generated in the electrical path connecting the conversion circuit. As is characterized by and a conducting state operation means for operating the energization conditions of the magnetic resistance adjusting means.

  In the above invention, the resonance determination unit and the energization state operation unit are provided, whereby the resonance frequency of the LC filter can be separated from the voltage fluctuation frequency by the operation of the energization state with respect to the magnetoresistive variable unit. Thereby, the resonance of the LC filter due to the voltage fluctuation of the electric path can be avoided.

  The invention according to claim 2 is the invention according to claim 1, wherein the power conversion system is provided corresponding to each of the plurality of power conversion circuits, and on / off operation means for turning on / off the switching element. In the power conversion circuit other than the power conversion circuit connected to the LC filter having the variable inductor among the plurality of power conversion circuits, frequency setting means for variably setting the switching frequency of the switching element, and The lower limit value of the range that can be taken by the voltage fluctuation frequency by variably setting the switching frequency is set to be equal to or lower than the lower limit value of the range that can be taken by the resonance frequency by the operation of the energized state.

  In order to avoid a situation in which the reliability of the LC filter components deteriorates due to the resonance of the LC filter, for example, the resonance frequency of the LC filter is lower than the lowest of the assumed voltage fluctuation frequencies. It is also conceivable to configure the LC filter as described above. Here, in order to lower the resonance frequency, it is required to increase the inductance of the inductor constituting the LC filter. However, when the inductance is increased, the size of the inductor increases, and as a result, the size of the LC filter increases. In this case, there is a concern that the mountability of the LC filter is deteriorated.

  Here, in the said invention, the lower limit of the range which the said voltage fluctuation frequency can take is set to below the lower limit of the range which the said resonance frequency can take. This is because the inductance of the inductor constituting the LC filter is set without imposing a restriction that the resonance frequency of the LC filter is lower than the lowest frequency among the assumed voltage fluctuation frequencies. Such a setting can be realized because the resonance determination unit and the energization state operation unit are provided. Therefore, according to the above-described invention, in order to avoid resonance of the LC filter, it is possible to avoid an increase in the size of the inductor constituting the LC filter, and thus an increase in the size of the LC filter.

The lineblock diagram of the power conversion system concerning a 1st embodiment. The figure which shows the production | generation method of the operation signal by the pulse width modulation concerning the embodiment. The block diagram of the variable inductor concerning the embodiment. The flowchart which shows the procedure of the resonance frequency switching process concerning the embodiment. The frequency response function of the transmissibility of the LC filter concerning the embodiment. The time chart which shows an example of the resonance frequency switching process concerning the embodiment. Sectional drawing of the variable inductor concerning 2nd Embodiment. Sectional drawing of the variable inductor concerning the embodiment. Sectional drawing of the variable inductor concerning the embodiment. The figure which shows the relationship between the gap and inductance of the variable inductor concerning the embodiment. Sectional drawing of the variable inductor concerning 3rd Embodiment. The lineblock diagram of the power conversion system concerning a 4th embodiment. The flowchart which shows the procedure of the resonance frequency switching process concerning the embodiment. Sectional drawing of the variable inductor concerning other embodiment. Sectional drawing of the variable inductor concerning other embodiment.

(First embodiment)
Hereinafter, a first embodiment in which a control device according to the present invention is applied to a vehicle (for example, a hybrid vehicle) including a rotating machine as an in-vehicle main machine will be described with reference to the drawings.

  As shown in FIG. 1, a high voltage battery 10 as a DC power source is a secondary battery whose terminal voltage is, for example, 100 V or more (288 V). As the high voltage battery 10, for example, a lithium ion secondary battery or a nickel hydride secondary battery can be used.

  The high voltage battery 10 is connected in parallel with a main machine inverter 20, a first auxiliary machine inverter 30, and a second auxiliary machine inverter 40. Specifically, the high-voltage battery 10 is connected to the main machine LC filter 21 via the first positive electrode side line Lp1 and the first negative electrode side line Ln1, and the main machine LC filter 21 includes the main machine inverter 20. It is connected. A motor generator 23 as an in-vehicle main machine is connected to the main machine inverter 20, and a drive wheel 24 is connected to a rotor of the motor generator 23. Incidentally, in this embodiment, the main machine LC filter 21 includes a main machine capacitor 25 (for example, a film capacitor) as a passive element and a wiring inductor 26. In the present embodiment, a synchronous rotating machine (for example, IPMSM) is used as the motor generator 23.

  The main machine inverter 20 includes switching elements S ¥ p, S ¥ n (¥ = u, v, w) for connecting the positive side and the negative side of the output terminal of the main device LC filter 21 to the terminals of the motor generator 23. ), And a three-phase AC voltage is applied to the motor generator 23. In the present embodiment, IGBTs are used as the switching elements S ¥ p and S ¥ n.

  The high voltage battery 10 also includes a second positive electrode side line Lp2 connected to the first positive electrode side line Lp1 and a second negative electrode side line Ln2 connected to the first negative electrode side line Ln1. A first auxiliary LC filter 31 is connected. The first auxiliary LC filter 31 is connected to the first auxiliary inverter 30. The first auxiliary inverter 30 is connected to an electric compressor driving electric motor (hereinafter referred to as a compressor electric motor 33) that constitutes the in-vehicle air conditioner 34. Here, the first auxiliary LC filter 31 includes a first capacitor 35 and a first variable inductor 36 as passive elements. In the present embodiment, a synchronous motor (for example, SPMSM) is used as the compressor motor 33.

  Similarly to the main machine inverter 20, the first auxiliary machine inverter 30 connects each of the positive terminal side and the negative terminal side of the output terminal of the first auxiliary machine LC filter 31 to the terminal of the compressor motor 33. This is a DC / AC converter circuit comprising three series connection bodies of switching elements, and applies a three-phase AC voltage to the compressor motor 33.

  The high voltage battery 10 further includes a third positive electrode side line Lp3 connected to the second positive electrode side line Lp2 and a third negative electrode side line Ln3 connected to the second negative electrode side line Ln2. A second auxiliary LC filter 41 is connected. The second auxiliary LC filter 41 is connected to the second auxiliary LC filter 41. The second auxiliary inverter 40 is connected to a blower fan driving electric motor (hereinafter referred to as a blower electric motor 43) constituting the in-vehicle air conditioner 34. Here, like the first auxiliary LC filter 31, the second auxiliary LC filter 41 includes a second capacitor 45 and a second variable inductor 46 as passive elements. . In the present embodiment, a synchronous motor (for example, SPMSM) is used as the blower motor 43.

  The second auxiliary inverter 40 is a DC / AC converter circuit, like the first auxiliary inverter 30. In the present embodiment, the configurations of the first auxiliary inverter 30 and the second auxiliary inverter 40 are the same as the configuration of the main inverter 20. For this reason, in FIG. 1, detailed illustration of these inverters 30 and 40 for auxiliary machines is omitted.

  The main machine inverter 20 is energized by a microcomputer (hereinafter, main machine microcomputer 27). Specifically, the main machine microcomputer 27 controls the switching element S ¥ # (# = p, n) constituting the main machine inverter 20 in order to control the control amount (for example, torque) of the motor generator 23 to the command value. By outputting the operation signal g ¥ #, the switching elements S ¥ # are turned on / off.

  On the other hand, the first auxiliary inverter 30 is energized by a microcomputer (hereinafter referred to as a first auxiliary microcomputer 37). In detail, the first auxiliary machine microcomputer 37, like the main machine microcomputer 27, controls the control amount (for example, the rotation speed) of the compressor motor 33 to its command value. These switching elements are turned on and off by outputting an operation signal to the switching elements constituting the. The first auxiliary microcomputer 37 takes in the detection value of the first current sensor 38 that detects the current flowing through the first capacitor 35.

  On the other hand, the second auxiliary inverter 40 is energized by a microcomputer (hereinafter referred to as a second auxiliary microcomputer 47). Specifically, the second auxiliary machine microcomputer 47, like the main machine microcomputer 27, controls the control amount (for example, the rotation speed) of the blower motor 43 to the command value. These switching elements are turned on and off by outputting an operation signal to the switching elements constituting the. The second auxiliary microcomputer 47 captures the detection value of the second current sensor 48 that detects the current flowing through the second capacitor 45.

  Incidentally, in this embodiment, each of the main machine microcomputer 27, the first auxiliary machine microcomputer 37, and the second auxiliary machine microcomputer 47 includes a central processing unit (CPU) and a memory, and a program stored in the memory. Is software processing means for executing the above in the CPU. Moreover, the said command value used in the process of these microcomputers 27, 37, and 47 is input from a high-order control apparatus, for example.

  Further, in the present embodiment, each of the first current sensor 38 and the second current sensor 48 constitutes a “detection unit”. In addition, in this embodiment, each of the main machine microcomputer 27, the first auxiliary machine microcomputer 37, and the second auxiliary machine microcomputer 47 that performs the on / off operation of the switching element S ¥ # by pulse width modulation is “on / off operation means”. Is configured.

  Subsequently, the control amount of the motor generator 23 by the main machine microcomputer 27, the control amount of the compressor motor 33 by the first auxiliary microcomputer 37, and the blower motor 43 by the second auxiliary microcomputer 47 are controlled. The control of the control amount will be further described. In the present embodiment, the above-described processing in the microcomputers 27, 37, and 47 is the same processing, so the processing in the main-machine microcomputer 27 will be described as an example.

  In this embodiment, in order to control the control amount of the motor generator 23 to a command value, the main machine microcomputer 27 operates a command voltage (command value of the output voltage of the main machine inverter 20) applied to the motor generator 23. As shown in FIG. 2, this is performed by a well-known triangular wave PWM process. More specifically, the main microcomputer 27 first determines a signal D ¥ (“” obtained by standardizing the three-phase command voltage V ¥ * (¥ = u, v, w) as the operation amount with the input voltage VDC of the main inverter 20. The PWM signal g ¥ is generated based on a comparison of the magnitude of the “modulated wave” and the triangular wave signal that is the carrier signal tc. Based on the PWM signal g ¥ and the logically inverted signal of the PWM signal g ¥, the main microcomputer 27 generates an operation signal g ¥ # through a dead time giving process.

  Hereinafter, the frequency of the carrier signal used to generate the operation signal of the main machine inverter 20 is referred to as the main machine carrier frequency fcm, and the operation signals of the first auxiliary machine inverter 30 and the second auxiliary machine inverter 40 are generated. The frequency of the carrier signal used in the above will be referred to as an accessory carrier frequency. In the present embodiment, from the viewpoint of reducing the ripple of the input voltage of the main machine inverter 20, the first auxiliary machine inverter 30, and the second auxiliary machine inverter 40, the main machine carrier frequency fcm and the auxiliary machine carrier frequency are , Are set to not match.

  Next, the first and second variable inductors 36 and 46 constituting the first and second auxiliary LC filters 31 and 41 will be described with reference to FIG. Here, in the present embodiment, the first and second variable inductors 36 and 46 have the same structure. Therefore, in the present embodiment, the configuration of the variable inductor will be described below using the first variable inductor 36 as an example unless otherwise specified.

  As shown in FIG. 3, the first variable inductor 36 includes a core 36a, a part of the second positive line Lp2 wound around the core 36a, an auxiliary winding 36b wound around the core 36a, and a magnetic A saturation switch 36c is provided. Here, in this embodiment, a toroidal core is used as the core 36a. In the present embodiment, the auxiliary winding 36b constitutes “magnetic resistance variable means”.

  The magnetic saturation switch 36 c is turned on and off by the first auxiliary microcomputer 37. Specifically, when the magnetic saturation switch 36c is turned on, a current flows through the auxiliary winding 36b using the power source 36d as a power supply source to magnetically saturate the first variable inductor 36. On the other hand, when the magnetic saturation switch 36c is turned off, the energization to the auxiliary winding 36b is stopped, and the magnetic saturation of the first variable inductor 36 is eliminated.

  Such a configuration of the first variable inductor 36 is for avoiding an increase in the size of the first variable inductor 36 while avoiding resonance of the first auxiliary LC filter 31.

  In other words, as shown in FIG. 1, the main unit capacitor 25 is charged and discharged due to the driving of the main unit inverter 20, so that the harmonic current flows in the electric path between the main unit inverter 20 and the high voltage battery 10. Flows. When the harmonic current flows, voltage fluctuations (potential difference Vs between the first positive electrode side line Lp1 and the first negative electrode side line Ln1) occur in the electric path. The voltage fluctuation occurs, for example, when a voltage drop occurs in the electrical path due to a current flowing through a wiring inductor existing in the electrical path. Here, in FIG. 1, the wiring inductor contributing to the voltage fluctuation is illustrated by “50”.

  The frequency of the voltage fluctuation is twice the main engine carrier frequency fcm. This is because the period during which the voltage vector of the main inverter 20 becomes a zero voltage vector appears twice in one cycle of the carrier signal tc, and the charging period and discharging period of the main machine capacitor 25 appear alternately twice. It is to do. Note that the main machine inverter 20 contributes greatly to the occurrence of ripple described above because the maximum value of the current flowing through the motor generator 23 is larger than the maximum value of the current flowing through the compressor motor 33. This is because the charging / discharging current of the capacitor 25 is larger than the charging / discharging current of the first capacitor 35.

  Here, in the present embodiment, in the main unit microcomputer 27, the main unit carrier frequency fcm (in other words, the switching frequency of the switching element S ¥ #) can be variably set within a predetermined range. This is a setting for overheating protection of the switching element S ¥ # constituting the main machine inverter 20. Specifically, from the viewpoint of overheating protection due to switching loss, when the temperature in the main inverter 20 is high, the main carrier frequency fcm is decreased. In the present embodiment, the main unit carrier frequency fcm variable setting process by the main unit microcomputer 27 constitutes a “frequency setting unit”.

  When the main machine carrier frequency fcm is changed by the main machine microcomputer 27, the frequency of the voltage fluctuation can be close to the resonance frequency of the first auxiliary machine LC filter 31. In this case, the current flowing through the first auxiliary LC filter 31 increases. As a result, the effective value of the current flowing through the first capacitor 35 constituting the first auxiliary LC filter 31 exceeds the rated current of the first capacitor 35, or the first auxiliary LC filter 31 is constituted. If the effective value of the current flowing through the first variable inductor 36 exceeds the rated current of the first variable inductor 36, the reliability of the first auxiliary LC filter 31 may be reduced. In this case, the ripple of the input voltage of the first auxiliary inverter 30 cannot be reduced by the first auxiliary LC filter 31, and the reliability of the compressor motor 33 may be reduced.

  In order to cope with such a problem, for example, the first auxiliary LC filter 31 has a resonance frequency lower than the frequency of the voltage fluctuation corresponding to the lowest frequency of the assumed main engine carrier frequency fcm. It is also conceivable to construct the LC filter 31 for auxiliary equipment. However, in this case, the physique of the inductor constituting the first auxiliary LC filter 31 increases, and as a result, the physique of the first auxiliary LC filter 31 increases. In this case, the mountability of the first auxiliary LC filter 31 may be deteriorated.

  Therefore, in the present embodiment, the first variable inductor 36 shown in FIG. 3 is used. In the present embodiment, in particular, the lower limit value of the range that can be taken by the voltage fluctuation frequency by variably setting the main engine carrier frequency fcm is the range that the resonance frequency of the first auxiliary LC filter 31 can be taken by the resonance frequency switching process described later. Is set below the lower limit of. On the premise of such a configuration, in this embodiment, the resonance frequency switching process of the first auxiliary LC filter 31 is performed.

  FIG. 4 shows the procedure of the resonance frequency switching process according to the present embodiment. This process is repeatedly executed by the first auxiliary microcomputer 37, for example, at a predetermined cycle.

  In this series of processes, first, in step S10, a current detected by the first current sensor 38 (hereinafter, capacitor current Ic) is acquired. In the present embodiment, the processing of this step constitutes “acquiring means”.

  In the subsequent step S12, it is determined whether or not the capacitor current Ic (more specifically, the peak value of the capacitor current Ic) has exceeded its allowable upper limit value Ilimit. This process is for determining whether the frequency of the voltage fluctuation is near the resonance frequency of the first auxiliary LC filter 31 (the first auxiliary LC filter 31 is resonating). It is. This process is performed in view of the fact that the ripple of the capacitor current Ic increases when the first auxiliary LC filter 31 resonates. In the present embodiment, the processing of this step constitutes “resonance determination means”.

  Incidentally, the smaller the allowable upper limit value Ilimit is set, the voltage fluctuation frequency when switching the resonance frequency of the first auxiliary LC filter 31 by the processing of steps S16 and S18 described later, and the first auxiliary machine immediately before switching. The difference from the resonance frequency of the LC filter 31 for use increases.

  If an affirmative determination is made in step S12, in steps S14 to S18, the magnetic saturation switch 36c is toggled from one of the on operation and the off operation to the other in accordance with the current operation state of the magnetic saturation switch 36c. To switch automatically. Specifically, in step S14, it is determined whether or not the magnetic saturation switch 36c is currently turned on.

  If an affirmative determination is made in step S14, the process proceeds to step S16, and the magnetic saturation switch 36c is switched to an off operation. For this reason, energization to the auxiliary winding 36b is stopped, the magnetic saturation of the first variable inductor 36 is eliminated, and the magnetic resistance is lowered. As a result, the inductance L of the first variable inductor 36 increases, and as a result, as shown in FIG. 5, the resonance frequency fr of the first auxiliary LC filter 31 decreases from “fra1” to “fra2”. To do. That is, the voltage fluctuation frequency is separated from the resonance frequency of the first auxiliary LC filter 31.

  On the other hand, if a negative determination is made in step S14, the process proceeds to step S18, and the magnetic saturation switch 36c is switched to the ON operation. For this reason, energization to the auxiliary winding 36 b is started, and the magnetic resistance increases due to the magnetic saturation of the first variable inductor 36. As a result, the inductance L of the first variable inductor 36 is lowered. As a result, as shown in FIG. 5, the resonance frequency fr of the first auxiliary LC filter 31 is changed from “fra2” to “fra1”. And rise. That is, the voltage fluctuation frequency is separated from the resonance frequency of the first auxiliary LC filter 31.

  Incidentally, in the present embodiment, the processing of steps S14 to S18 constitutes an “energized state operating means”.

  If a negative determination is made in step S12, or if the processes in steps S16 and S18 are completed, the series of processes is temporarily terminated.

  Incidentally, the resonance frequency switching process for the second variable inductor 46 is executed by the second auxiliary microcomputer 47.

  FIG. 6 shows an example of the resonance frequency switching process according to the present embodiment. Specifically, FIG. 6A shows the transition of the capacitor current Ic, and FIG. 5B shows the transition of the operation state of the magnetic saturation switch 36c.

  As shown in the figure, at time t1 when the capacitor current Ic exceeds the allowable upper limit value Ilimit, an off operation command is output from the first auxiliary microcomputer 37 to the magnetic saturation switch 36c. Therefore, thereafter, the magnetic saturation switch 36c is switched to the off operation, and the resonance frequency of the first auxiliary LC filter 31 is switched from “fra1” to “fra2”. Thereby, resonance of the first auxiliary LC filter 31 is avoided, and the capacitor current Ic can be reduced.

  Thereafter, at time t2, the capacitor current Ic again exceeds the allowable upper limit value Ilimit. Therefore, thereafter, the magnetic saturation switch 36c is switched to the ON operation, and the resonance frequency of the first auxiliary device LC filter 31 is switched from “fra2” to “fra1”. Thereby, resonance of the first auxiliary LC filter 31 is avoided, and the capacitor current Ic can be reduced.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) The first variable inductor 36 including the core 36a and the auxiliary winding 36b wound around the core 36a is used as the inductor constituting the first auxiliary LC filter 31. When it is determined that the first auxiliary LC filter 31 resonates, the energization state of the auxiliary winding 36b is switched so that the resonance frequency of the first auxiliary LC filter 31 is separated from the voltage fluctuation frequency. It was. Thereby, resonance of the first auxiliary LC filter 31 can be preferably avoided.

  (2) The lower limit value of the range that the voltage fluctuation frequency can take is set to be less than the lower limit value fra2 of the possible range of the resonance frequency fr by operating the energization state of the auxiliary winding 36b by variably setting the main machine carrier frequency fcm. According to such setting, in order to avoid resonance of the first auxiliary LC filter 31, it is possible to avoid an increase in the size of the first auxiliary LC filter 31.

  (3) When it is determined that the capacitor current Ic exceeds the allowable upper limit value Ilimit, it is determined that the first auxiliary LC filter 31 resonates. According to such a configuration, even if the first auxiliary microcomputer 37 cannot obtain information on the main carrier frequency fcm from the main microcomputer 27, the first auxiliary microcomputer 37 side has the first auxiliary microcomputer 37 side. The resonance of the machine LC filter 31 can be determined.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the present embodiment, the configuration of the first and second variable inductors 36 and 46 is changed. In the present embodiment, the first variable inductor 36 will be described as an example.

  A configuration of the first variable inductor 36 according to the present embodiment will be described with reference to FIGS. 7 and 8. Here, FIG. 7 is a side cross-sectional view of the first variable inductor 36, and FIG. 8 is a cross-sectional view taken along line AA of FIG. In FIG. 8, the second positive line Lp2 is not shown.

  As shown in FIG. 7, the first variable inductor 36 includes a first core 36e, a part of the second positive line Lp2 wound around the first core 36e, a second core 36f, and a gap adjustment. Switch 36g and a bimorph piezo actuator (hereinafter referred to as bimorph piezo 36h).

  The first core 36e includes a disk-shaped end plate portion 36e1, a middle foot portion 36e2, and an outer foot portion 36e3. Specifically, the middle foot portion 36e2 is provided so as to protrude from the center of the plate surface of the end plate portion 36e1 (a surface extending in a direction orthogonal to the thickness direction of the end plate portion 36e1), and has a cylindrical shape. . More specifically, the middle foot portion 36e2 is provided so as to extend in a direction orthogonal to the plate surface of the end plate portion 36e1. A part of the second positive electrode side line Lp2 is wound around the middle foot portion 36e2.

  The outer foot portion 36e3 is provided so as to protrude from the end of the plate surface of the end plate portion 36e1 in the same direction as the protruding direction of the middle foot portion 36e2, and has a substantially annular shape. More specifically, the outer foot portion 36e3 is provided outside the middle foot portion 36e2 on the plate surface of the end plate portion 36e1, and is provided so as to extend in a direction orthogonal to the plate surface of the end plate portion 36e1. Yes. The middle foot portion 36e2 and the outer foot portion 36e3 have the same distance from the tip to the plate surface of the end plate portion 36e1 in these protruding directions.

  The second core 36f and the bimorph piezo 36h have a disk shape. The second core 36f is opposite to the end plate portion 36e1 of the middle foot portion 36e2 and the outer foot portion 36e3 in the direction in which the middle foot portion 36e2 and the outer foot portion 36e3 protrude from the plate surface of the end plate portion 36e1. On the side. Thereby, the second core 36f forms a magnetic circuit together with the first core 36e. Further, in the front view of the plate surface of the end plate portion 36e1, the region where the second core 36f is projected onto the end plate portion 36e1 and the region where the bimorph piezo 36h is projected onto the end plate portion 36e1 are the end plate portion 36e1 and Match. Thus, the bimorph piezo 36h is sandwiched between the cores 36e and 36f without protruding from the first core 36e and the second core 36f.

  The gap adjustment switch 36g is turned on / off by the first auxiliary microcomputer 37. Specifically, when the gap adjustment switch 36g is turned on, as shown in FIG. 9, the bimorph piezo 36h is bent and displaced in an arc shape with the power supply 36d as a power supply source, whereby the first core 36e and the second core 36e A gap is formed between the cores 36f. As a result, the magnetic resistance of the first variable inductor 36 increases, the inductance L decreases, and the resonance frequency of the first auxiliary LC filter 31 increases (see FIG. 10).

  On the other hand, when the gap adjusting switch 36g is turned off, the bimorph piezo 36h is not bent and displaced, and the gap is reduced. As a result, the magnetic resistance of the first variable inductor 36 decreases, the inductance L increases, and the resonance frequency of the first auxiliary LC filter 31 decreases.

  Next, the resonance frequency switching process according to the present embodiment will be described.

  The resonance frequency switching process according to the present embodiment can be performed by a process according to the process shown in FIG. Specifically, the process of step 14 in FIG. 4 is replaced with a process for determining whether or not the gap adjustment switch 36g is turned on. Also, the process in step S16 in FIG. 4 is replaced with a process for switching the gap adjustment switch 36g to an off operation, and the process in step S18 in FIG. 4 is replaced with a process for switching the gap adjustment switch 36g to an on operation.

  As described above, in the present embodiment, the first variable inductor 36 including the first core 36e, the second core 36f, and the bimorph piezo 36h is used as the inductor constituting the first auxiliary LC filter 31. Adopted. When it is determined that the first auxiliary LC filter 31 resonates, the energization state of the gap adjustment switch 36g is set so that the resonance frequency of the first auxiliary LC filter 31 is separated from the voltage fluctuation frequency. Switched. Even with such a configuration, it is possible to obtain the same effect as that obtained in the first embodiment.

  In the present embodiment, bimorph piezo 36h is used. The bimorph piezo 36h has a simple configuration and a large amount of displacement. Therefore, according to the present embodiment, for example, the amount of change in the resonance frequency is ensured by securing the amount of change in the gap, as compared with a variable inductor that changes the gap by a laminated piezo actuator provided in the middle foot portion. It is also possible to obtain an effect that the cost can be reduced. As a result, as a capacitor constituting the first auxiliary LC filter 31, the capacitance change rate with respect to temperature change is large (temperature characteristics are bad), or the capacitance change rate with respect to DC voltage change is high. It is also possible to use a large-capacity, high-dielectric-constant ceramic capacitor that is large (poor voltage characteristics).

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the second embodiment.

  In the present embodiment, as shown in FIG. 11, in addition to the bimorph piezo 36h, the first variable inductor 36 includes the auxiliary winding 36i for magnetic saturation described in the first embodiment. Here, FIG. 11 is a side sectional view of the first variable inductor 36. In the present embodiment, in order to supply power from the power source 36d to the auxiliary winding 36i, the magnetic saturation switch 36j is provided as described in the first embodiment. The magnetic saturation switch 36j is turned on and off by the first auxiliary microcomputer 37.

  Next, the resonance frequency switching process according to the present embodiment will be described.

  In the present embodiment, the resonance frequency switching process can be performed by a process according to the process shown in FIG. Specifically, the process of step 14 in FIG. 4 is replaced with a process of determining whether or not both the gap adjustment switch 36g and the magnetic saturation switch 36j are turned on. Also, the process in step S16 in FIG. 4 is replaced with a process for switching both of the switches 36g and 36j to an off operation, and the process in step S18 in FIG. 4 is replaced with a process for switching both the switches 36g and 36j into an on operation. .

  According to the present embodiment described above, the amount of change in the resonance frequency of the first auxiliary LC filter 31 can be increased.

(Fourth embodiment)
Hereinafter, the fourth embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the present embodiment, the resonance determination method of the first auxiliary LC filter 31 is changed.

  FIG. 12 shows the overall configuration of the power conversion system according to this embodiment. In FIG. 12, the same members as those shown in FIG. 1 are given the same reference numerals for the sake of convenience.

  As shown in the figure, the first auxiliary microcomputer 37 and the second auxiliary microcomputer 47 receive signals related to the main carrier frequency fcm from the main microcomputer 27. In the present embodiment, the first current sensor 38 and the second current sensor 48 are not provided in the power conversion system.

  FIG. 13 shows a procedure of resonance frequency switching processing according to the present embodiment. This process is repeatedly executed by the first auxiliary microcomputer 37, for example, at a predetermined cycle. In FIG. 13, the same processes as those shown in FIG. 4 are given the same reference numerals for the sake of convenience.

  In this series of processes, first, the main engine carrier frequency fcm is acquired in step S10a.

  In the subsequent step S12a, the absolute value of the difference between the double frequency of the main carrier frequency fcm and the resonance frequency fr of the first auxiliary LC filter 31 when the magnetic saturation switch 36c is turned on is less than a predetermined value Δ. It is determined whether or not. This process is a process for determining whether or not the first auxiliary LC filter 31 is resonating, similar to the process in step S12 of FIG. Incidentally, in this embodiment, the processing of this step constitutes “resonance determination means”.

  When an affirmative determination is made in step S12a, it is determined that the first auxiliary LC filter 31 is resonating, and the process proceeds to step S14.

  If a negative determination is made in step S12a, or if the processes in steps S16 and S18 are completed, the series of processes is temporarily terminated.

  According to the present embodiment described above, it is possible to obtain an effect according to the effect obtained in the first embodiment.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  The “first core” and “second core” included in the variable inductor are not limited to those described in the second and third embodiments. For example, as shown in FIGS. 14 and 15, an E core may be adopted as the first core 50a included in the variable inductor 50, and an I core may be adopted as the second core 50b. Here, the first core 50a includes the end plate portion 50a1, the middle foot portion 50a2 protruding from the center portion of the plate surface of the end plate portion 50a1, and the middle foot portion 50a2 from the end of the plate surface of the end plate portion 50a1. The outer leg part 50a3 provided so that it might protrude in the same direction as the protrusion direction is provided. A rectangular (rectangular) bimorph piezo 50d is sandwiched between the first core 50a and the second core 50b. In addition, an auxiliary winding 50c for magnetic saturation is wound on one of the pair of outer legs 50a3, and a part of the second positive electrode side line Lp2 is wound on the other. 14 is a side sectional view of the variable inductor 50, and FIG. 15 is an AA sectional view of FIG. In FIG. 15, the second positive line Lp2 and the auxiliary winding 50c are not shown.

  In the configuration shown in FIG. 14, the winding position of the auxiliary winding is not limited to the outer foot portion 50a3, and may be, for example, the end plate portion 50a1, the middle foot portion 50a2, or the second core 50b. . Further, the number of auxiliary windings is not limited to one and may be plural. Specifically, for example, the auxiliary winding may be wound around both the first core and the second core.

  In the first embodiment, the “core” is not limited to the toroidal core, and may be a core having another shape such as a cylindrical core.

  In the third embodiment, the switching timing of the operation state of the bimorph piezo 36h and the magnetic saturation switch 36j is synchronized, and the resonance frequency of the LC filter is switched in a binary manner, but this is not restrictive. For example, the operation timing of the bimorph piezo 36h and the magnetic saturation switch 36j may be changed to switch the resonance frequency of the LC filter in three stages.

  The “detecting means” is not limited to the one configured with a current sensor, and may be configured with a temperature sensor. In this case, the “resonance determination means” may determine that the auxiliary LC filter is resonating when the auxiliary microcomputer determines that the temperature detected by the temperature sensor exceeds the threshold temperature. . This technique is based on the fact that when the frequency of the voltage fluctuation is close to the resonance frequency, the ripple current flowing in the capacitor constituting the variable inductor increases and the temperature of the capacitor increases. That is, the capacitor temperature is a state quantity having a correlation with the capacitor current.

  Further, for example, the “detecting means” may include a voltage detecting means (voltage sensor) for detecting the input voltage of the LC filter. Since the capacitor current increases as the input voltage increases, the input voltage becomes an electrical state quantity having a correlation with the capacitor current. In this case, the “resonance determination unit” may determine that the LC filter is resonating when it is determined that the peak value of the detected voltage is equal to or greater than the threshold value.

  The “resonance determination means” is not limited to determining resonance based on the peak value of the state quantity, and may be, for example, determining resonance based on the effective value of the state quantity.

  Further, the “resonance determination unit” is not limited to that exemplified in the fourth embodiment. For example, the resonance may be determined only when it is determined that the frequency twice the main engine carrier frequency fcm matches the resonance frequency fr of the first auxiliary LC filter 31.

  The carrier signal tc is not limited to a triangular wave signal, and may be a sawtooth wave signal, for example.

  ・ "In-vehicle auxiliary machines" are not limited to electric motors for driving electric compressors and blower fans. For example, in a vehicle including an internal combustion engine in addition to a rotating machine as an in-vehicle main machine, an electric motor incorporated in a water pump that circulates cooling water of the internal combustion engine may be used. Furthermore, the “on-vehicle auxiliary machine” is not limited to an electric motor but may be a heater that generates heat when energized.

  The “DC power supply” is not limited to the high-voltage battery 10 and includes, for example, an AC power supply (for example, commercial power supply) and a rectifying means (for example, a converter or a full-wave rectifier circuit) that rectifies the output of the AC power supply. May be a power source.

  The number of inverters connected in parallel to the high voltage battery 10 may be two, or four or more. Further, when there are three or more auxiliary inverters, it is not necessary that the resonance frequency can be variably set for all of the LC filters connected to the inverters other than the main inverter 20 among the plurality of inverters.

  -There may be a plurality of loads (motor generators) having a rated output larger than other loads among the loads connected to each of the plurality of inverters. That is, there are a plurality of factors that greatly increase the ripple of the input voltage.

  In the first embodiment, the lower limit of the range that can be taken by the voltage fluctuation frequency by variably setting the main engine carrier frequency fcm, and the lower limit of the range that can be taken by the resonance frequency fr by operating the auxiliary winding 36b. It may be set to fra2. Even in this case, an increase in the size of the first auxiliary LC filter 31 can be avoided.

  The “power converter circuit” is not limited to a DC / AC converter circuit whose output terminal is connected to an input terminal of a load (motor generator 23, electric motors 33, 43) as a power supply destination. For example, it may be a step-down converter that steps down the voltage of the high voltage battery 10 and outputs it to an in-vehicle auxiliary battery as a power supply destination. Even in this case, in a configuration in which a plurality of power conversion circuits including a step-down converter are connected in parallel to a DC power supply, if an LC filter may be connected to the input side of these power conversion circuits, for example, a step-down converter There is a possibility that resonance of the LC filter may occur due to the on / off operation of the switching element provided. For this reason, it is considered that the application of the present invention is effective.

  -The application object of this invention is not restricted to a vehicle.

  DESCRIPTION OF SYMBOLS 10 ... High voltage battery, 20 ... Main machine inverter, 21 ... Main machine LC filter, 30 ... First auxiliary machine inverter, 31 ... First auxiliary machine LC filter, 36 ... First variable inductor, 36b ... Auxiliary winding, 40 ... second auxiliary inverter, 41 ... second auxiliary LC filter, 46 ... second variable inductor, S ¥ # ... switching element.

Claims (8)

A plurality of power conversion circuits (20, 30, 40) that are connected in parallel to the DC power supply (10) and convert the input voltage into a predetermined value by an on / off operation of the switching element (S ¥ #);
LC filters (21, 31, 41) interposed between each of the plurality of power conversion circuits and the DC power supply and provided corresponding to each of the plurality of power conversion circuits;
Applied to a power conversion system comprising:
The LC filter (31, 41) connected to some of the plurality of power conversion circuits (30, 40) includes a capacitor (35, 45) and a variable inductor (36, 46; 50). Prepared,
The variable inductor includes magnetic resistance variable means (36b; 36h; 36h, 36i; 50c, 50d) capable of variably setting the magnetic resistance of the variable inductor by an operation in an energized state.
Resonance determining means for determining whether or not the LC filter having the variable inductor resonates;
The resonance frequency of the LC filter having the variable inductor is separated from a voltage fluctuation frequency generated in an electric path connecting the DC power source and the power conversion circuit, on condition that the resonance is determined by the resonance determination unit. Energizing state operating means for operating the energizing state for the magnetoresistive variable means;
A control device for a variable inductor, comprising: The power conversion system includes:
An on / off operation means that is provided corresponding to each of the plurality of power conversion circuits and that performs an on / off operation of the switching element;
In a power conversion circuit other than the power conversion circuit connected to the LC filter having the variable inductor among the plurality of power conversion circuits, frequency setting means for variably setting the switching frequency of the switching element;
With
The lower limit value of the range that can be taken by the voltage fluctuation frequency by the variable setting of the switching frequency is set to be equal to or lower than the lower limit value of the range that can be taken by the resonance frequency by the operation of the energized state. The variable inductor control device described. The variable inductor is:
The end plate portion (36e1; 50a1), the middle foot portion (36e2; 50a2) provided so as to protrude from the center portion of the plate surface of the end plate portion, and the middle portion from the end portion of the plate surface of the end plate portion A first core (36e; 50a) having an outer foot (36e3; 50a3) provided so as to protrude in the same direction as the protruding direction of the foot;
A second core that is provided on the opposite side of the end plate in the projecting direction of each of the middle foot and the outer foot of the first core and that forms a magnetic circuit together with the first core. Core (36f; 50b),
With
The magnetoresistive variable means includes a plate-shaped bimorph piezo actuator (36h; 50d) sandwiched between the first core and the second core.
The energization state operation means is configured to energize the bimorph piezo actuator so as to adjust a gap formed between the first core and the second core so as to separate the resonance frequency from the voltage fluctuation frequency. The variable inductor control device according to claim 1, wherein the control device is operated. The magnetoresistive variable means includes an auxiliary winding (36i; 50c) wound around at least one of the first core and the second core,
The energization state operation means operates an energization state of the auxiliary winding so as to switch magnetic saturation of the variable inductor or cancellation of the magnetic saturation so as to separate the resonance frequency from the voltage fluctuation frequency. The variable inductor control device according to claim 3. The variable inductor includes a core (36a),
The magnetoresistive variable means includes an auxiliary winding (36b) wound around the core,
The energization state operation means operates the energization state of the auxiliary winding so as to switch magnetic saturation of the variable inductor or cancellation of the magnetic saturation so as to separate the resonance frequency from the voltage fluctuation frequency. The variable inductor control device according to claim 1 or 2. The power conversion system includes detection means (38, 48) for detecting a current flowing through the capacitor or a state quantity correlated with the current,
The resonance determining means includes
An acquisition means for acquiring a detection value of the detection means;
The condition according to claim 1, wherein the LC filter having the variable inductor is determined to resonate on the condition that the detection value acquired by the acquisition unit exceeds a threshold value. Control device for variable inductor. The power conversion system includes an on / off operation unit that is provided corresponding to each of the plurality of power conversion circuits and that performs on / off operation of the switching element by pulse width modulation based on a magnitude comparison of a modulated wave and a carrier signal,
The resonance determining means includes
An acquisition means for acquiring the frequency of the carrier used for pulse width modulation of a power conversion circuit other than the power conversion circuit connected to the LC filter having the variable inductor among the plurality of power conversion circuits,
The variable according to any one of claims 1 to 5, wherein it is determined whether or not the LC filter having the variable inductor resonates based on the frequency of the carrier acquired by the acquisition means. Inductor control device. Each of the plurality of power conversion circuits is a DC / AC conversion circuit,
In-vehicle auxiliary equipment (33, 43) is connected to the power conversion circuit (30, 40) connected to the LC filter having the variable inductor,
A rotating machine (23) as an in-vehicle main machine is connected to a power conversion circuit (20) other than the power conversion circuit connected to the LC filter having the variable inductor among the plurality of power conversion circuits. The control device for a variable inductor according to any one of claims 1 to 7.

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