JP2012223008A - Power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion device capable of achieving low loss without deterioration of control performance by performing control so that a region with a low requirement for voltage utilization factor becomes a region with a high requirement for voltage utilization factor.SOLUTION: A power conversion device has: voltage amplitude setting means 52a setting a command voltage amplitude Vamp(a voltage amplitude) on the basis of a command torque Tcmd(a request torque) and a rotation number N; voltage phase setting means 52e setting a command voltage phase Vp(a voltage phase) on the basis of a deviation torque ΔT; and voltage command setting means 51a communicating to a converter 10 a command step-up voltage Vconv(a step-up command signal) for stepping up a voltage so as to be in an overmodulation region even in a sinusoidal wave region, on the basis of the command voltage amplitude Vampand the command voltage phase Vp. According to such a configuration, since the control is performed so that a region with a low requirement for voltage utilization factor becomes a region with a high requirement for voltage utilization factor, low loss can be achieved without deteriorating control performance in the whole region.

Description

  The present invention relates to a power conversion device including a converter, an inverter, and a controller.

  Conventionally, the phase of the output voltage of the power conversion circuit is set based on the difference value between the required torque and the actual torque (actual torque including estimated torque), and the phase and the rotation speed (also referred to as rotation speed) of the rotating machine. The same applies hereinafter), and an example of a technique for setting the norm of the output voltage vector of the power conversion circuit and outputting the operation signal to the switching element of the power conversion circuit based on the norm and the phase is disclosed ( For example, see Patent Document 1). According to the technique of Patent Document 1, in a region where a high voltage utilization factor is required when the modulation factor exceeds the threshold (for example, an overmodulation region), the number of times of switching is reduced and the modulation factor is equal to or less than the threshold, Even when compared with a low-demand region (for example, a sine wave region), the loss can be reduced without impairing the control performance.

JP 2009-232530 A

  However, in a region where the modulation rate is equal to or less than the threshold and the voltage utilization rate is low, there is a problem in that reduction in loss cannot be achieved because normal switching control is performed.

  The present invention has been made in view of the above points. Conventionally, the modulation rate is equal to or lower than the threshold and the voltage usage rate is low, and the modulation rate is equal to or higher than the threshold and the voltage usage rate is required. An object of the present invention is to provide a power converter capable of reducing the number of times of switching in the entire region by controlling in a high region and achieving a low loss without impairing the control performance.

  The invention according to claim 1, which has been made in order to solve the above problems, includes a converter that performs boosting, an inverter that converts and outputs the boosted voltage, and a controller that individually controls the operation of the converter and the inverter. A voltage amplitude setting means for setting a voltage amplitude based on the required torque and the rotational speed, and a voltage phase is set based on a difference value (deviation) between the required torque and the actual torque. In a region where the modulation factor is less than the threshold value and the demand for the voltage utilization rate is low based on the voltage phase setting means to be performed, the voltage amplitude set by the voltage amplitude setting means and the voltage phase set by the voltage phase setting means Even so, a boost command signal for boosting is transmitted to the converter so that a demand for a voltage utilization rate at which the modulation rate exceeds the threshold is high. And having a voltage command setting unit which.

  In general, the “region with low voltage utilization requirement” is often set as a sine wave region, and the “region with high voltage utilization requirement” is often set as an overmodulation region. It is not limited to. Hereinafter, the sine wave region and the overmodulation region will be described as examples. The “boost command signal” may be an analog signal or a digital signal. “Modulation rate” is a value calculated by, for example, amplitude of voltage command / (DC power supply voltage / 2). An arbitrary numerical value can be set as the “threshold value”, and actually a numerical value in a range from 1.00 to 1.15 is often set. “Voltage utilization rate” is a physical quantity that quantifies the magnitude of the output voltage vector of the inverter.

  According to this configuration, the voltage command setting means transmits a boost command signal for boosting the voltage so as to be in a region where the request for voltage utilization is high even in a region where the request for voltage utilization is low. Boost control is performed so that control can be performed in a region where voltage requirement is low in a region where voltage requirement is low, so that low loss can be achieved without impairing control performance in the entire region. can do.

  The invention according to claim 2 is characterized in that the voltage command setting means sets a voltage value inputted to the converter as a lower limit value of the boost command signal. According to this configuration, the modulation factor can be always 1.00 or more (or more than a threshold value), so that low loss and controllability improvement can be achieved in the entire area.

  According to a third aspect of the present invention, the voltage command setting means includes a boost command control means for controlling the boost command signal so that a modulation rate of the voltage amplitude set by the voltage amplitude setting means becomes a command modulation rate. And a correction voltage setting means for correcting the boost command signal so as to obtain a predetermined output margin with respect to the current voltage phase. According to this configuration, a predetermined output margin can be obtained by the correction voltage setting unit while controlling the command modulation rate by the boost command control unit. Therefore, it is possible to achieve a low loss without losing control performance with a margin.

  The invention according to claim 4 is characterized in that the boost command control means uses the command modulation rate in a numerical range (including a single numerical value) such that the control region becomes an overmodulation region. According to this configuration, the control region becomes the overmodulation region only by commanding the command modulation rate. Therefore, it is possible to more reliably achieve a reduction in loss without impairing control performance.

  According to a fifth aspect of the present invention, the correction voltage setting means includes an output margin calculating means for obtaining an output margin until the voltage phase limit value is reached, an output margin limiter for limiting the output margin, and the output margin. And a voltage margin calculation means for calculating a corresponding voltage margin and setting the correction voltage based on the voltage margin. According to this configuration, since the voltage margin calculation means calculates the voltage margin and then sets the correction voltage, it is possible to achieve low loss and improved controllability while ensuring a predetermined output margin.

  According to a sixth aspect of the present invention, the output margin calculating means performs calculation using a mathematical model using one or more variables of voltage amplitude, voltage phase, rotation speed, torque, and current. The output margin is obtained by one or both of the reference methods for referring to the map using one or more of the variables as an argument. According to this configuration, an output margin can be reliably obtained by an arithmetic method or a reference method, and a reduction in loss can be achieved more reliably without impairing control performance.

  The invention according to claim 7 is characterized in that the voltage margin calculation means is one or more variables of voltage amplitude, voltage phase, rotation speed, torque, and current based on the output margin obtained by the output margin calculation means. The correction voltage is obtained by one or both of an arithmetic method for performing an arithmetic operation using a mathematical model and a reference method for referring to a map using one or more of the variables as an argument. To do. According to this configuration, the correction voltage is reliably obtained by the calculation method or the reference method, and the reduction in loss can be achieved more reliably without impairing the control performance.

  The invention according to claim 8 is characterized in that the output margin limiter limits the output margin with an upper limit of an output value that can be handled only by torque feedback by phase control with respect to the required torque. According to this configuration, the modulation factor can be always 1.00 or more (or more than a threshold value), so that low loss can be achieved without impairing the control performance in the entire area.

It is a schematic diagram which shows the structural example of a power converter device. It is a schematic diagram which shows the structural example of a controller. It is a schematic diagram which shows the structural example of a voltage amplitude setting means. It is a schematic diagram which shows the 1st structural example of a correction voltage setting part. It is a graph which shows the relationship between output margin restriction | limiting (voltage phase restriction | limiting) and rotation speed. It is a graph which shows the example of a restriction | limiting of an output margin. It is a graph which shows the relationship between voltage amplitude / rotation speed and torque. It is a schematic diagram which shows the 2nd structural example of a correction voltage setting part. It is a mimetic diagram showing the example of composition of vehicles.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Unless otherwise specified, “connect” means electrical connection. Each figure shows elements necessary for explaining the present invention, and does not show all actual elements. When referring to directions such as up, down, left and right, the description in the drawings is used as a reference. “Setting” includes determination based on reference of a map or the like, calculation (calculation) based on a mathematical model represented by a function formula or the like. “·” Is used as a symbol representing multiplication. The characteristic line is not limited to the straight line or the curve shown in the figure.

[Embodiment 1]
The first embodiment will be described with reference to FIGS. In FIG. 1, the structural example of a power converter device is shown with a schematic diagram. FIG. 2 is a schematic diagram showing a configuration example of the controller. FIG. 3 is a schematic diagram showing a configuration example of the voltage amplitude setting means. FIG. 4 is a schematic diagram illustrating a first configuration example of the correction voltage setting unit. FIG. 5 is a graph showing the relationship between the output margin limit (voltage phase limit) and the rotational speed. FIG. 7 is a graph showing the relationship between voltage amplitude / rotation speed and torque.

The power converter shown in FIG. 1 has a function of converting the power supplied from the power source E and supplying it to the rotating machine 40. The power conversion device includes a converter 10, an inverter 20, a controller 50, and the like. Below, each element is demonstrated. Although the command is transmitted from the "external apparatus" corresponding to ECU60 is for example the command torque Tcmd ^* and command rotation speed NCMD ^*, etc., in this embodiment in order to simplify the explanation on behalf of the command torque Tcmd ^* explain. This command torque Tcmd ^* corresponds to “request torque”.

  The converter 10 converts the input voltage Vdc (for example, 300 [V], etc.) supplied from the power source E through the smoothing capacitor C1 to the input voltage Vinv (for example, 660 [V], etc.) required by the inverter 20. Responsible for conversion and output. For example, a battery (storage battery) or a fuel cell is used as the power source E.

The converter 10 includes drive circuits M11 and M12, switching elements Q11 and Q12, diodes D11 and D12, a coil L10, and the like. Drive circuits M11 and M12 have transistors and the like, and drive and control switching elements Q11 and Q12 according to a boost command signal (that is, command boost voltage Vconv ^* ) transmitted from controller 50. As the switching elements Q11 and Q12, a semiconductor element having a switching function (for example, an IGBT or a power transistor) is used. The switching elements Q11 and Q12 of this example are connected in series to form a half bridge. The diodes D11 and D12 are connected in parallel to the switching elements Q11 and Q12, respectively, and both function as freewheeling diodes. For example, a choke coil or the like is used as the coil L10.

  The connection point of the switching elements Q11 and Q12 is connected to the plus electrode of the power source E via the coil L10. The output terminal of the converter 10 is connected to the DC power supply terminal of the inverter 20. Specifically, the high potential side terminal (the upper terminal in the drawing) of the switching element Q11 is connected to the high potential side of the inverter 20, and the low potential side terminal (the lower terminal in the drawing) of the switching element Q12 is connected to the low potential side of the inverter 20. Connect to. The low potential side terminal of the switching element Q12 is connected to the negative electrode of the power source E.

  The inverter 20 has a function of converting the power of the input voltage Vinv supplied from the converter 10 and outputting it to the rotating machine 40. A smoothing capacitor C <b> 2 is connected between the converter 10 and the inverter 20. Capacitor C2 has a function of smoothing potential fluctuations in the output voltage of converter 10 (that is, input voltage Vinv). Since the specific configuration and operation of the inverter 20 are well known, illustration and description are omitted. In accordance with the number of phases of the rotating machine 40, for example, it is assumed that power is converted in three phases (U phase, V phase, W phase).

  As the current sensor 30, a sensor capable of detecting the phase current I flowing through the rotating machine 40 (that is, the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw) is used. For example, a magnetic proportional sensor, an electromagnetic induction sensor, a Faraday effect sensor, a current transformer sensor, and the like are applicable.

  In the present embodiment, a three-phase motor generator (denoted as “MG” in the drawing) having both an electric function and a power generation function is applied to the rotating machine 40. The rotating machine 40 includes a resolver 41 corresponding to a “rotation sensor”. The resolver 41 outputs a detection signal (such as a SIN detection signal Ss or a COS detection signal Sc) based on the electrical angle of a rotating member (for example, a main shaft or a rotor) provided in the rotating machine 40.

The controller 50 controls the operation of the converter 10, the inverter 20, and the like. The controller 50 includes a converter control mechanism 51, an inverter control mechanism 52, and the like. Converter control mechanism 51 is a boost command signal that controls the operation of converter 10 based on a command (command torque Tcmd ^* ) transmitted from ECU 60 (external device), a variable Vx transmitted from inverter control mechanism 52, or the like. That is, the command boost voltage Vconv ^* ) is output. The variable Vx corresponds to, for example, an output margin variable Voutput or a command voltage amplitude Vamp ^* . Of these, the command voltage amplitude Vamp ^* corresponds to “voltage amplitude”. The inverter control mechanism 52 includes a command (that is, command torque Tcmd ^* ) transmitted from the ECU 60, a phase current I (that is, U-phase current Iu, V-phase current Iv, and W-phase current Iw) transmitted from the current sensor 30, and a resolver. Based on the detection signal transmitted from 41, a control signal for controlling the operation of the inverter 20 (that is, the operation signal Vsw ^* ) is output. Hereinafter, specific configuration examples and operations of the converter control mechanism 51 and the inverter control mechanism 52 will be described.

  One structural example of the converter control mechanism 51 and the inverter control mechanism 52 is shown in FIG. Converter control mechanism 51 includes voltage command setting means 51a and the like. A specific configuration example and operation of the voltage command setting means 51a will be described with reference to FIG.

The voltage command setting means 51a shown in FIG. 3 includes an output margin variable Voutput, a command voltage amplitude Vamp ^* transmitted from a voltage amplitude setting means 52a described later, an input voltage Vdc (or an input voltage Vinv indicated by a two-dot chain line), and the like. The command boost voltage Vconv ^* is set based on the above and is output to the converter 10. The voltage command setting unit 51a includes a correction voltage setting unit 51a1, joining units 51a2 and 51a5, a limiter unit 51a3, calculation units 51a4 and 51a7, a PI control unit 51a6, and the like.

The output margin variable Voutput is a variable (variable group) used for setting the output margin ΔP. For example, voltage (that is, power supply voltage such as input voltage Vdc and input voltage Vinv, voltage command, actual voltage, etc.), rotation speed N, torque (that is, command torque Tcmd ^* , estimated torque T, etc.), current (that is, U-phase current Iu) , V phase current Iv, W phase current Iw, etc.), command voltage phase, actual voltage phase, phase limit value, and the like. Any one of the variables can be applied, or two or more variables can be applied in any combination. In this embodiment, in order to simplify the description, the rotational speed N and the command torque Tcmd ^* are applied.

The correction voltage setting unit 51a1 sets and outputs the correction voltage Vofs based on the output margin variable Voutput (in this embodiment, the command torque Tcmd ^* and the rotation speed N). The correction voltage setting unit 51a1 corresponds to “correction voltage setting means”. Specific configuration examples and operations will be described later (see FIG. 4).

The calculation unit 51a4 performs division based on a command voltage amplitude Vamp ^* and an input voltage Vdc (or input voltage Vinv) transmitted from a voltage amplitude setting unit 52a described later, and outputs the result as an actual modulation factor M. Expressed as an equation, M = Vinv / Vamp ^* . The adding unit 51a5 obtains a difference value (deviation) based on the actual modulation rate M and the limited modulation rate Mlim ^* transmitted from the calculation unit 51a4, and outputs it as a deviation modulation rate Md. Expressed by the equation, Md = Mlim ^* −M. It is preferable to use a numerical range (including a single numerical value) for limiting modulation factor Mlim ^{* such} that the control region becomes an overmodulation region. This limited modulation factor Mlim ^* may be stored as a map or the like in a recording medium (such as a ROM), may be calculated based on a mathematical model represented by a functional equation, or may be transmitted from the ECU 60. .

The PI control unit 51a6 performs PI (proportional integration) control based on the deviation modulation factor Md, and sets and outputs a command modulation factor M ^* . More specifically, the command modulation rate M ^* is set and output so as to control the command boost voltage Vconv ^* so that the modulation rate of the command voltage amplitude Vamp ^* (voltage amplitude) becomes the limit modulation rate Mlim ^* . The PI control unit 51a6 corresponds to “boost command control means”. Since the specific configuration and operation are well known, illustration and description are omitted.

The calculation unit 51a7 performs multiplication based on the command modulation rate M ^* transmitted from the PI control unit 51a6 and the input voltage Vinv, and outputs the result as the effective voltage Veff. Expressed by the equation, Veff = M ^* · Vinv. The adder 51a2 obtains a difference value (deviation) based on the correction voltage Vofs and the effective voltage Veff described above, and outputs the difference value (deviation) as the boosted voltage Vconv. Expressed by the equation, Vconv = Veff−Vofs. The limiter unit 51a3 limits the boosted voltage Vconv and outputs it as the command boosted voltage Vconv ^* . The boost voltage Vconv will be described later with reference to a restriction example (see FIG. 6).

The voltage command setting means 51a configured as described above is based on the output margin variable Voutput (particularly the command voltage phase Vp ^* ), the command voltage amplitude Vamp ^* , the input voltage Vdc (or the input voltage Vinv), and the like. The boost voltage Vconv ^* (boost command signal) can be set and output. That is, the limiter unit 51a3 limits the boosted voltage Vconv so that the boosted voltage Vconv can be prevented from exceeding the maximum value / minimum value of the boosted voltage allowed for the converter 10, and the sine wave region where the modulation factor is equal to or less than the threshold value. Even so, the overmodulation region can be reliably controlled. An arbitrary numerical value can be set as the threshold, and for example, a numerical value in a range from 1.00 to 1.15 is often set. The lower limit value of the command boost voltage Vconv ^* is preferably a voltage value of the input voltage Vdc input to the converter 10 (or a voltage calculated based on the input voltage Vinv).

Returning to FIG. 2, the inverter control mechanism 52 includes a voltage amplitude setting means 52a, a modulation factor setting means 52b, an operation signal output means 52c, an adder 52d, a voltage phase setting means 52e, a torque estimation means 52f, and a current vector setting means 52g. , Rotation speed setting means 52h, angle setting means 52i, and the like. Since the inverter control mechanism 52 of this embodiment performs control based on the command torque Tcmd ^* transmitted from the ECU 60, it can be said to be a “torque control mechanism”.

The voltage amplitude setting unit 52a sets the above-described command voltage amplitude Vamp ^* based on the command transmitted from the ECU 60 (that is, the command torque Tcmd ^* ), the rotational speed N transmitted from the rotational speed setting unit 52h, and the like. Output. An example of setting the command voltage amplitude Vamp ^* is arbitrary and well known, and therefore illustration and description thereof are omitted. Modulation rate setting means 52b sets and outputs set voltage amplitude Vm ^* based on command voltage amplitude Vamp ^* and input voltage Vinv transmitted from voltage amplitude setting means 52a.

The joining unit 52d obtains a difference value (deviation) based on a command torque Tcmd ^* transmitted from the ECU 60 and an estimated torque T transmitted from torque estimation means 52f described later, and outputs the difference value ΔT. Expressed as an equation, ΔT = Tcmd ^* −T. The voltage phase setting means 52e sets and outputs a command voltage phase Vp ^* based on the deviation torque ΔT.

The voltage phase setting unit 52e of this embodiment includes a PI control unit 52e1, a limiter unit 52e2, and the like. The PI control unit 52e1 performs PI control based on the deviation torque ΔT and outputs a voltage phase command Vp. The limiter unit 52e2 limits the voltage phase command Vp within a predetermined value range and outputs the command voltage phase Vp ^* . An appropriate numerical value range can be set as the predetermined value range. For example, -10 to +190 [deg] is set according to the type and rating of the rotating machine 40, or -100 to +100 [deg] is set on the dq coordinate with reference to the q axis.

The operation signal output unit 52c drives the switching element in the inverter 20 based on the set voltage amplitude Vm ^* transmitted from the modulation factor setting unit 52b, the command voltage phase Vp ^* transmitted from the voltage phase setting unit 52e, and the like. An operation signal Vsw ^* for control is output. The operation signal Vsw ^* can include a pulse width modulation (PWM) signal.

  The angle setting means 52 i outputs the rotation angle θ based on the detection signal (SIN detection signal Ss, COS detection signal Sc, etc.) transmitted from the resolver 41. The rotation angle θ is an angle based on a predetermined position in the rotating machine 40. The predetermined position can be arbitrarily set. For example, an angle based on the installation position (0 degree) of the north marker can be detected. The rotation speed setting means 52h sets and outputs the rotation speed N described above based on the rotation angle θ transmitted from the angle setting means 52i.

  The current vector setting means 52g includes the phase current I (U-phase current Iu, V-phase current Iv, W-phase current Iw) detected by the current sensor 30, and the rotation angle θ of the rotating machine 40 transmitted from the angle setting means 52i. Based on the above, the current vector is set and output. The current vector corresponds to a combination of d-axis current Id and q-axis current Iq, a combination of current amplitude and current phase, or the like. In this embodiment, a combination of d-axis current Id and q-axis current Iq is applied. The torque estimation means 52f sets and outputs the estimated torque T described above based on the current vector transmitted from the current vector setting means 52g. This estimated torque T corresponds to “actual torque”.

  Next, a configuration example and operation of the correction voltage setting unit 51a1 will be described with reference to FIG. The correction voltage setting unit 51a1 of FIG. 4 includes an output margin setting device 51aa, an output margin limiter 51ab, a voltage margin setting device 51ac, an output margin limit value setting device 51ae, and the like.

The output margin setter 51aa sets and outputs an output margin ΔP based on the output margin variable Voutput (in this embodiment, the command torque Tcmd ^* and the rotational speed N). This output margin setting device 51aa corresponds to “output margin calculating means”. An example of setting the output margin ΔP will be described with reference to FIG.

FIG. 5 is a graph showing the relationship in which the vertical axis represents the voltage phase limit corresponding to the output margin limit value ΔPlim, and the horizontal axis represents the rotational speed N corresponding to the output margin variable Voutput. A characteristic line L1 shows a change in the voltage phase limit value Vlim that defines the limit value of the voltage phase. The voltage phase limit value Vlim may be stored as a map or the like in a recording medium (for example, ROM) in the correction voltage setting unit 51a1, or may be calculated based on a mathematical model represented by a functional equation or the like. May be transmitted. A characteristic line L2 indicates a change in the command voltage phase Vp ^* currently commanded to the inverter 20. The characteristic lines L1 and L2 both change with the rotational speed N. That is, not only a straight line indicated by a solid line and a curve indicated by a two-dot chain line, there are various changes depending on the characteristics of a control target to be controlled (rotary machine 40 in this embodiment). If the current value of the rotational speed N is the rotational speed N1, the characteristic lines L1 and L2 intersect at output values P1 and P2, respectively. A difference value between the output value P1 and the output value P2 is obtained as an output margin ΔP. Expressed by the equation, ΔP = | P2−P1 |.

  Instead of the setting example described above, one of an arithmetic method for performing an arithmetic operation using a mathematical model and a reference method for referring to a map using one or more variables as arguments among variables Vx included in an output margin variable Voutput. Alternatively, the output margin ΔP may be set and output by both methods.

In the case of the calculation method, the number of pole pairs is “p”, the d-axis inductance is “Ld”, the q-axis inductance is “Ld”, the voltage amplitude is “V”, the rotation speed is “N”, and the q-axis Assuming that the voltage phase with respect to δ is “δ” and the permanent magnetic flux is “Φ”, the torque T (any of estimated torque, actual torque, and command torque is applicable) satisfies the following voltage equation (1). . The resistance component is ignored. According to this voltage equation, the output margin ΔP is calculated by the following equation (2).
T = p / LdLq × (V / N) sinδ × {(Ld−Lq) (V / N) cosδ + LqΦ} (1)
ΔP = N × T (2)

Returning to FIG. 4, the output margin limit value setter 51ae sets and outputs the minimum output margin value ΔPmin based on the output margin variable Voutput (in this embodiment, the command torque Tcmd ^* and the rotational speed N). The output margin limiter 51ab is configured to limit the output margin based on the output margin ΔP transmitted from the output margin setter 51aa, the minimum output margin value ΔPmin transmitted from the output margin limit value setter 51ae, and the rotational speed N. A value ΔPlim is set and output. An example of setting the output margin limit value ΔPlim will be described later (see FIG. 6). The output margin limiter 51ab corresponds to “output margin limiter means”.

  The voltage margin setter 51ac calculates a voltage margin corresponding to the output margin ΔP based on the output margin limit value ΔPlim transmitted from the output margin limiter 51ab and the voltage margin variable Vvolt, and calculates the voltage margin. Based on this, the correction voltage Vofs is set and output. This voltage margin setting device 51ac corresponds to “voltage margin calculating means”. A setting example of the correction voltage Vofs will be described later (see FIG. 7).

The voltage margin variable Vvolt is a variable (variable group) used to set the voltage margin ΔV. For example, voltage (that is, power supply voltage such as input voltage Vdc and input voltage Vinv, voltage command, actual voltage, etc.), rotation speed N, torque (that is, command torque Tcmd ^* , estimated torque T, etc.), current (that is, phase current I, etc.) Real current, command current, etc.). Any one of the variables can be applied, or two or more variables can be applied in any combination. In this embodiment, the rotation speed N is applied to simplify the description.

  The correction voltage setting unit 51a1 configured as described above can set and output the correction voltage Vofs based on the output margin variable Voutput and the voltage margin variable Vvolt.

An example of setting the output margin limit value ΔPlim will be described with reference to FIG. FIG. 6 is a graph showing a relationship in which the output margin ΔP is the vertical axis and the output margin variable Voutput is the horizontal axis. More specifically, FIG. 6A shows an example of limiting with the minimum output margin value ΔPmin, FIG. 6B shows an example of limiting with a filter, and FIG. 6C shows an example of limiting with a staircase pattern. Shown in In either example, the rotation speed N is applied as the output margin variable Voutput. As other variables, a voltage (that is, a power supply voltage such as the input voltage Vdc or the input voltage Vinv, a voltage command, an actual voltage, or the like), a torque (that is, a command torque Tcmd ^* , an estimated torque T, or the like) may be applied.

  In the setting example shown in FIG. 6A, the output margin ΔP is limited based on the minimum output margin value ΔPmin indicated by the characteristic line L4, and the output margin limit value ΔPlim is output. Such a characteristic of the output margin limit value ΔPlim is indicated by a characteristic line L3. The rotational speed reference value Nth is the rotational speed at which the output margin limit value ΔPlim (characteristic line L3) and the minimum output margin value ΔPmin (characteristic line L4) intersect (the same applies to FIGS. 6B and 6C). ). When the rotational speed N is equal to or higher than the rotational speed reference value Nth (N ≧ Nth), the output margin limit value ΔPlim exceeds the minimum output margin value ΔPmin. Output as ΔPlim. On the other hand, when the rotation speed N is less than the rotation speed reference value Nth (N <Nth), “0” is output as the output margin limit value ΔPlim regardless of the rotation speed N. Therefore, the portion of the characteristic line L3 indicated by the two-dot chain line is limited.

  The setting example shown in FIG. 6B uses the minimum output margin value ΔPmin indicated by the characteristic line L4 as a reference, further limits the output margin ΔP based on the filter, and outputs the output margin limit value ΔPlim. Such a characteristic of the output margin limit value ΔPlim is indicated by a characteristic line L5. When the rotational speed N is less than the rotational speed reference value Nth (N <Nth), “0” is output as the output margin limit value ΔPlim regardless of the rotational speed N, as in FIG. On the other hand, when the rotation speed N is equal to or higher than the rotation speed reference value Nth (N ≧ Nth), the rotation speed N is changed in a curved shape by a filter (for example, a function). In the example of FIG. 6B, as the number of revolutions N increases, the difference from the output margin limit value ΔPlim (characteristic line L3) is made asymptotic.

  The setting example shown in FIG. 6C uses the minimum output margin value ΔPmin indicated by the characteristic line L4 as a reference, further limits the output margin ΔP stepwise, and outputs the output margin limit value ΔPlim. Such a characteristic of the output margin limit value ΔPlim is indicated by a characteristic line L6. When the rotational speed N is less than the rotational speed reference value Nth (N <Nth), “0” is output as the output margin limit value ΔPlim regardless of the rotational speed N, as in FIG. On the other hand, when the rotation speed N is equal to or higher than the rotation speed reference value Nth (N ≧ Nth), the rotation speed is changed stepwise. In the example of FIG. 6C, the limit is changed based on the rotation speed Nx. The rotation speed Nx is the rotation speed at which the output margin limit value ΔPlim (characteristic line L6) of the step change intersects with the output margin limit value ΔPlim (characteristic line L3). That is, when the rotation speed is greater than the reference speed Nth and less than the rotation speed Nx (Nth ≦ N <Nx), the output is limited to a step shape, and when the rotation speed is greater than or equal to Nx (N ≧ Nx), the output margin ΔP corresponding to the rotation speed N Is output as an output margin limit value ΔPlim.

  In addition to the control shown in FIGS. 6A to 6C described above, other conditions may be imposed. Other conditions can be set arbitrarily. For example, the above-mentioned voltage is equal to or higher than (or exceeds) the minimum voltage. The minimum voltage is, for example, the power supply voltage before boosting by the converter 10 (either the detected voltage value of the converter or a value including the voltage error until the detected voltage value is actually input to the inverter 20), the minimum output margin The power supply voltage including the necessary voltage amplitude assumed from the above corresponds. The minimum output margin corresponds to a derivation output or a correction output.

The derived output is based on the output derived from the difference between the current command torque Tcmd ^* , the estimated torque T, and the rotation speed N from the maximum required torque assumed by the transient response, or the difference from the maximum torque in the steady state. This is the derived output. The corrected output is an output obtained by adding a loss output generated due to electrical / mechanical to the output obtained from the derived output. As a specific example, if the rotational speed N is 4000 [rpm] and the maximum torque request is 50 [Nm], the minimum output margin is 20.9 [KW]. Similarly, if the rotational speed N is 4000 [rpm] and the command torque Tcmd ^* is 20 [Nm], the minimum output margin is 8.4 [KW].

The above-described setting example of the output margin limit value ΔPlim can be similarly applied to the operation of the limiter unit 51a3 shown in FIG. In this case, the vertical axis shown in FIGS. 6A to 6C may be replaced with “boosted voltage Vconv” in parentheses. In this way, the characteristic of the command boost voltage Vconv ^* becomes the characteristic line L3 in FIG. 6A, the characteristic of the command boost voltage Vconv ^* becomes the characteristic line L5 in FIG. 6B, and in FIG. The characteristic of the command boost voltage Vconv ^* is the characteristic line L6.

Next, a setting example of the correction voltage Vofs will be described with reference to FIG. FIG. 7 is a graph showing the relationship between the voltage amplitude / rotation number as the vertical axis and the torque Tx as the horizontal axis. The voltage amplitude Vm corresponds to, for example, a power supply voltage (that is, an input voltage Vdc, an input voltage Vinv, etc.), a voltage command, an actual voltage, or the like. The correction voltage Vofs corresponds to a difference value of the voltage amplitude Vm. In order to simplify the explanation, the voltage amplitude / rotation speed (that is, Vm / N) is assumed to be a variable X. The torque Tx corresponds to a command torque Tcmd ^* , an estimated torque T, or the like. The difference value (lateral width in the figure) of the torque Tx corresponds to the output margin ΔP. A characteristic line L7 defines the relationship between the variable X and the torque Tx. In this embodiment, it is defined by a quadratic function as an example, but various characteristic lines according to the characteristics of the controlled object (in this embodiment, the rotating machine 40) can be defined. If the current value of the torque Tx is the torque value T2, the torque value T1 can be specified by providing a difference value of the output margin ΔP. Based on these torque values T2 and T1, the characteristic line L7 intersects with variable values X2 and X1, respectively. A difference value between the variable value X2 and the variable value X1 is a margin value ΔX. This margin value ΔX corresponds to a “voltage margin”. Therefore, the correction voltage Vofs is obtained by multiplying the margin value ΔX by the torque Tx. Expressed by the equation, Vofs = T2 · ΔX = T2 · | X2-X1 |.

  Instead of the setting example described above, one of an arithmetic method that performs an arithmetic operation using a mathematical model and a reference method that refers to a map using one or more variables as an argument among variables Vx included in a voltage margin variable Vvolt. Alternatively, the correction voltage Vofs may be set and output by both methods.

The case of the calculation method will be described. The torque T is calculated by the voltage equation of the above formula (1). When the solution is obtained for the voltage amplitude “V”, the voltage amplitude equation is obtained from the voltage phase as shown in the following equation (3). When the right side of Expression (3) is expressed as a function format “f (T, δ)”, the correction voltage Vofs can be calculated by the following Expression (4).
Vofs / N = 1/2 × {−LqΦ / (Ld−Lq) / cosδ + 4TLdLq / (Ld−Lq) / (p × sinδcosδ)} (3)
Vofs = N × f (T, δ) (4)

According to the first embodiment described above, the following effects can be obtained. First, corresponding to claim 1, voltage amplitude setting means 52a for setting the voltage amplitude based on the command torque Tcmd ^* (requested torque) and the rotational speed N, command torque Tcmd ^* (requested torque) and estimated torque T ( Based on the difference value (deviation) from the actual torque), the voltage phase setting means 52e for setting the voltage phase, the command voltage amplitude Vamp ^* (voltage amplitude) set by the voltage amplitude setting means 52a, and the voltage phase setting means 52e Based on the command voltage phase Vp ^* (voltage phase) set by, even if the voltage utilization factor is low (sine wave region), the voltage utilization factor is high (overmodulation region). Thus, the voltage boost setting unit 51a for transmitting the command boost voltage Vconv ^* (boost command signal) for boosting to the converter 10 is used (see FIGS. 2 to 7). According to this configuration, the boost control is performed so that even in the sine wave region, the control can be positively performed in the overmodulation region, so that a low loss can be achieved without impairing the control performance in the entire region.

Corresponding to claim 2, voltage command setting means 51a has a configuration in which the voltage value of input voltage Vdc input to converter 10 is set as the lower limit value of command boosted voltage Vconv ^* (see FIGS. 3 and 6). According to this configuration, the modulation factor can be always 1.00 or more (or more than a threshold value), so that low loss can be achieved without impairing the control performance in the entire area.

Corresponding to claim 3, the voltage command setting means 51a includes a command boost voltage Vconv ^* so that the modulation factor of the command voltage amplitude Vamp ^* (voltage amplitude) set by the voltage amplitude setting means 52a becomes the limit modulation factor Mlim ^{* .} PI control unit 51a6 (boost command control unit) for controlling the voltage and correction voltage setting unit 51a1 (correction voltage setting unit ⁾ for correcting the command boost voltage Vconv ^* so as to obtain a predetermined output margin ΔP with respect to the current voltage phase ) (See FIG. 3). According to this configuration, a predetermined output margin ΔP can be obtained by the correction voltage setting unit 51a1 while the PI control unit 51a6 performs control so as to achieve the limited modulation rate Mlim ^* . Therefore, it is possible to achieve a low loss without losing control performance with a margin.

Corresponding to claim 4, the PI control unit 51a6 (step-up command control means) is configured to use a limited modulation factor Mlim ^* in a numerical range such that the control region becomes an overmodulation region (see FIG. 3). According to this configuration, the control region becomes an overmodulation region only by commanding the limited modulation rate Mlim ^* . Therefore, it is possible to more reliably achieve a reduction in loss without impairing control performance.

  Corresponding to claim 5, the correction voltage setting unit 51a1 (correction voltage setting means) includes an output margin setting device 51aa (output margin calculation means) for obtaining an output margin ΔP until the voltage phase limit value is reached, and an output margin ΔP. Output margin limiter 51ab (output margin limiter means) that limits the output margin, and a voltage margin setter 51ac (voltage margin calculation means) that calculates a voltage margin corresponding to the output margin ΔP and sets the correction voltage Vofs based on the voltage margin. (See FIGS. 4 and 7). According to this configuration, the voltage margin setter 51ac calculates the voltage margin and then sets the correction voltage Vofs. Therefore, while maintaining a predetermined output margin ΔP, a reduction in loss can be achieved without impairing control performance. Can do.

  Corresponding to claim 6, the output margin setting device 51aa uses an output margin variable Voutput (that is, voltage amplitude, voltage phase, rotation speed N, torque, current, etc.) and uses any one or more of the variables Vx. An output margin ΔP is obtained by one or both of an arithmetic method for performing an operation using a model and a reference method for referring to a map using one or more of variables Vx as an argument (FIGS. 4 and 4). 7). According to this configuration, the output margin ΔP is reliably obtained by the calculation method or the reference method, and the reduction in loss can be achieved more reliably without impairing the control performance.

  Corresponding to claim 7, the voltage margin setter 51ac is a voltage margin variable Vvolt (that is, voltage amplitude, voltage phase, rotational speed N, torque, current, etc.) based on the output margin ΔP obtained by the output margin setter 51aa. ) One or both of an arithmetic method for performing an operation using a mathematical model using one or more variables Vx and a reference method for referring to a map using any one or more of variables Vx as an argument Thus, the correction voltage Vofs is obtained (see FIGS. 4 and 7). According to this configuration, the correction voltage Vofs is reliably obtained by the calculation method or the reference method, and a reduction in loss can be more reliably achieved without impairing the control performance.

Corresponding to claim 8, the output margin limiter 51ab has, as an upper limit, an output value (rotation speed reference value Nth in FIG. 6) that can be handled only by torque feedback by phase control with respect to the command torque Tcmd ^* (requested torque). The output margin ΔP is limited (see FIG. 6). According to this configuration, the modulation factor can be always 1.00 or more (or more than a threshold value), so that low loss can be achieved without impairing the control performance in the entire area.

[Embodiment 2]
The second embodiment is a modification of the correction voltage setting unit 51a1 in the first embodiment. The second embodiment will be described with reference to FIG. The configuration and the like of the power conversion device are the same as those in the first embodiment, and in the second embodiment, differences from the first embodiment will be described in order to simplify the illustration and description. Therefore, the same elements as those used in Embodiment 1 are denoted by the same reference numerals, and description thereof is omitted.

The correction voltage setting unit 51a1 shown in FIG. 8 is different from the correction voltage setting unit 51a1 shown in FIG. 4 in that it further includes an adder 51ad. The adder 51ad corresponds to an “adjustment output unit”, and has a function of adjusting the correction voltage Vofs ^* set by the voltage margin setting unit 51ac and outputting it as the correction voltage Vofs. Specifically, addition (addition) is performed based on the correction voltage Vofs ^* transmitted from the voltage margin setter 51ac and the input voltage error Vinv_err, and the result is output as the correction voltage Vofs. Expressed as an expression, Vofs = Vofs ^* + Vinv_err.

The input voltage error Vinv_err is a voltage error relating to a control signal (that is, the operation signal Vsw ^* ) for controlling the operation of the inverter 20. This input voltage error Vinv_err may be stored as a map or the like in a recording medium (for example, a ROM), may be calculated based on a mathematical model represented by a functional equation, or may be transmitted from the ECU 60. In this way, by adding the input voltage error Vinv_err, the modulation factor can always be 1.00 or more (or more than a threshold value), so that low loss can be achieved without impairing the control performance in the entire area.

[Embodiment 3]
The third embodiment is an example in which the power conversion device shown in the first and second embodiments is applied to a transportation device, and will be described with reference to FIG. In FIG. 9, the structural example at the time of applying to a vehicle as an example of transport equipment is shown with a schematic diagram. The configuration of the power converter is the same as in the first and second embodiments. Therefore, in order to simplify the illustration and description, the same elements as those used in the first and second embodiments are denoted by the same reference numerals and the description thereof is omitted.

  A vehicle 100 shown in FIG. 9 is an example of a hybrid vehicle (split method) that can travel using both the rotating machine 40 and the internal combustion engine (torque generation source) as power sources. In addition to the inverter 20 and the rotating machine 40, the vehicle 100 includes a vehicle speed sensor 80, an acceleration sensor 85, an internal combustion engine 102, a battery 106, a generator 108, a power split mechanism 110, a PCU (power control unit) 112, wheels. 116 and the like.

  The vehicle 100 is configured to use both the internal combustion engine 102 and the rotating machine 40 as power sources, and transmit power generated in one or both to the wheels 116 to travel. The internal combustion engine 102 corresponds to, for example, a gasoline engine or a diesel engine, and generates power by burning hydrocarbon fuel. The internal combustion engine 102 transmits the generated power (rotational force) to the output shaft 104. The rotating machine 40 has a function of receiving power supplied from the PCU 112 to generate power, or a function of relaying power split from the power split mechanism 110, and transmits one or both powers to the rotary shaft 114 ( To the transmission shaft).

  The battery 106 is a storage / discharge unit capable of storing and discharging, for example, a secondary battery or a fuel cell. The generator 108 generates electric power using the power divided by the power split mechanism 110. A normal generator may be used, or a motor generator indicated by “MG” in parentheses may be used. The generated electric power is stored in the battery 106 through the PCU 112 or rotates the rotating machine 40.

  The PCU 112 is responsible for power transfer in the vehicle 100. Specifically, control for storing electric power generated by the generator 108 in the battery 106, control for supplying electric power for rotationally driving the rotating machine 40, and the like are performed. The PCU 112 includes, for example, a converter 10, an inverter 20, a battery ECU, and the like. The battery ECU controls the accumulation and release of electric power with the battery 106.

  The power split mechanism 110 has a function of splitting (distributing) the power generated in the internal combustion engine 102. That is, power is transmitted to one or both of the generator 108 and the rotating machine 40 in accordance with the state of the vehicle 100 (that is, the state such as running or stopping). The power split mechanism 110 can be arbitrarily configured. For example, the power split mechanism 110 includes a carrier, a sun gear, a planetary gear, and the like.

The controller 50 includes the voltage amplitude setting means 52a, the voltage phase setting means 52e, the voltage command setting means 51a, etc. shown in the first and second embodiments (see FIGS. 1 to 8). The ECU 60 can grasp the traveling state of the vehicle 100 based on the speed Vs transmitted from the vehicle speed sensor 80 and the acceleration As transmitted from the acceleration sensor 85. Further, based on the grasped traveling state of the vehicle 100 and the operation of the driver (mainly operation of an accelerator pedal, a brake pedal, etc.), the command torque Tcmd ^* (requested torque) is output to the controller 50. According to the third embodiment, since claims 1 to 8 are the same as those in the first and second embodiments, the operational effects corresponding to the respective embodiments can be obtained.

[Other Embodiments]
Although the form for implementing this invention was demonstrated according to Embodiment 1-3 in the above, this invention is not limited to the said form at all. In other words, various forms can be implemented without departing from the scope of the present invention. For example, the following forms may be realized.

  In the first to third embodiments described above, a three-phase generator motor is applied to the rotating machine 40 (see FIGS. 1 and 2). Instead of this form, other rotating machines may be applied. Examples of other rotating machines include a generator motor having a number of phases other than three phases (two phases or four phases or more), and a motor or a generator regardless of the number of phases. Since there is only a difference in the controlled object, the same effect as in the first and second embodiments can be obtained.

  In the first to third embodiments described above, the PI control unit 52e1 illustrated in FIG. 2 and the PI control unit 51a6 illustrated in FIG. 3 are configured to perform PI control including a proportional element and an integral element. Instead of this form, PID control may be performed including a differential element. PID control is shown in parentheses in FIGS. Depending on the performance and application of the rotating machine 40, the rotational speed N may change abruptly, and the control response of such a rotating machine 40 is improved.

  In the third embodiment described above, a hybrid vehicle (split method) that can run using both the rotating machine 40 and the internal combustion engine 102 as power sources is applied as the vehicle 100 (see FIG. 9). It can replace with this form and can also be applied to other vehicles provided with rotating machine 40. The other vehicle corresponds to, for example, a hybrid vehicle of another method (series method or parallel method) or a vehicle (so-called electric vehicle or fuel cell vehicle) that uses only the power of the rotating machine 40. Even if it is another vehicle, since only a form differs, the effect similar to Embodiment 1, 2 is acquired.

  In the first to third embodiments described above, the relationship between the “threshold value” and the “region where the request for the voltage utilization rate is low” and the “region where the request for the voltage utilization rate is high” is as follows. The region where the demand for the voltage utilization rate is low is defined as a region where the modulation factor exceeds the threshold value, and the region where the requirement for the voltage utilization rate is high. Instead of this form, using a reference voltage utilization rate that is a reference value that is separate from the threshold value and indicating the voltage utilization rate, a region that is equal to or less than the reference voltage utilization rate is defined as a “region where the voltage utilization rate is low”, A region exceeding the reference voltage utilization rate may be a “region where a high voltage utilization factor is required”. This can be easily realized by replacing “threshold” with “reference voltage utilization” in the first to third embodiments. Since only the difference between the reference values is obtained, the same effect as in the first to third embodiments can be obtained.

[Other Aspects of Invention]
Although the embodiments of the invention have been described above, the embodiments include not only the embodiments of the invention described in the claims but also other embodiments of the invention. Aspects of the present invention are listed below, and related explanations are given as necessary.

[Aspect 1] The correction voltage setting means comprises:
6. The adjustment output means for adjusting and outputting the correction voltage based on the correction voltage set by the voltage margin calculation means and a voltage error of the inverter. The power conversion device according to claim 1.

According to the configuration of the first aspect, the adjustment output unit (adder 51ad) adjusts the correction voltage Vofs ^* set by the voltage margin calculation unit (voltage margin setting unit 51ac) with the input voltage error Vinv_err and outputs the correction. It outputs as voltage Vofs (refer FIG. 8). In this way, by adding the input voltage error Vinv_err, the modulation factor can always be 1.00 or higher (or higher than the threshold value), so that low loss can be achieved without impairing the control performance in the entire area.

[Aspect 2] Power conversion control for controlling a power conversion device including a converter that performs boosting, an inverter that converts and outputs the boosted voltage, and a controller that individually controls the operation of the converter and the inverter In the method
Set the voltage amplitude based on the required torque and speed,
Set the voltage phase based on the difference between the required torque and the actual torque,
Based on the voltage amplitude set by the voltage amplitude setting means and the voltage phase set by the voltage phase setting means, the modulation rate is less than a threshold value and the modulation rate is low even in a region where the voltage utilization rate is low. A power conversion control method, wherein a boost command signal for boosting is transmitted to the converter so that a demand for a voltage utilization rate exceeding the threshold is high.

  According to the configuration of the aspect 2, the boost command signal for boosting so as to be in the overmodulation region even in the sine wave region is transmitted to the converter. Boost control is performed so that control is possible even in a region where the voltage utilization factor is low (sine wave region) and in a region where the voltage utilization factor is high (overmodulation region). Loss can be achieved.

10 Converter 20 Inverter 30 Current sensor 40 Rotating machine (control target)
41 Resolver (rotation sensor)
50 controller 51 converter control mechanism 51a voltage amplitude setting means 51a1 correction voltage setting unit 51aa output margin setting unit 51ab output margin limiter 51ac voltage margin setting unit 51ae output margin limit value setting unit 51a3 limiter unit 51a4, 51a7 calculation unit 51a6 PI control unit 52 Inverter control mechanism 60 ECU (external device)

Claims (8)

In a power converter comprising: a converter that performs boosting; an inverter that converts and outputs a boosted voltage; and a controller that individually controls the operation of the converter and the inverter.
Voltage amplitude setting means for setting the voltage amplitude based on the required torque and the rotational speed;
Voltage phase setting means for setting a voltage phase based on a difference value between the required torque and the actual torque;
Based on the voltage amplitude set by the voltage amplitude setting means and the voltage phase set by the voltage phase setting means, the modulation rate is less than a threshold value and the modulation rate is low even in a region where the voltage utilization rate is low. A voltage command setting means for transmitting a boost command signal for performing the boost so as to be in a region where a request for a voltage utilization rate exceeding the threshold is high;
The power converter characterized by having.   The power converter according to claim 1, wherein the voltage command setting unit sets a voltage value input to the converter as a lower limit value of the boost command signal. The voltage command setting means is
Step-up command control means for controlling the step-up command signal so that the modulation factor of the voltage amplitude set by the voltage amplitude setting means becomes the command modulation factor;
Correction voltage setting means for setting a correction voltage for correcting the boost command signal so as to obtain a predetermined output margin with respect to the current voltage phase;
The power converter according to claim 1, wherein the power converter is provided.   The power conversion apparatus according to claim 3, wherein the step-up command control means uses the command modulation rate in a numerical range such that a control region becomes an overmodulation region. The correction voltage setting means includes
An output margin calculating means for obtaining an output margin until the voltage phase limit value is reached;
Output margin limiter means for limiting the output margin;
Obtaining a voltage margin corresponding to the output margin, voltage margin calculating means for setting the correction voltage based on the voltage margin;
5. The power conversion device according to claim 3, wherein the power conversion device includes:   The output margin calculation means includes a calculation method for performing calculation using a mathematical model using any one or more variables of voltage amplitude, voltage phase, rotation speed, torque, and current, and any one or more of the variables. The power conversion device according to claim 5, wherein the output margin is obtained by one or both of reference methods for referring to a map using as a parameter.   The voltage margin calculation means uses one or more variables of voltage amplitude, voltage phase, rotation speed, torque, and current based on the output margin obtained by the output margin calculation means, using a mathematical model. The correction voltage is obtained by one or both of a calculation method for performing calculation and a reference method for referring to a map using one or more of the variables as an argument. Power converter.   8. The output margin limiter unit limits the output margin with an output value that can be handled only by torque feedback based on phase control on the required torque as an upper limit. The power converter described.

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