JP6939399B2 - Boost converter device - Google Patents

Description

The present invention relates to a boost converter device, and more particularly to a boost converter device including first and second boost converters.

Conventionally, as a boost converter device of this type, a device including first and second boost converters (first and second converters) has been proposed (see, for example, Patent Document 1). The first and second boost converters exchange power between the first power line to which the power storage device (battery) is connected and the second power line to which the electric load (inverter) is connected, accompanied by voltage conversion. They are lined up and connected in parallel. In this device, the first and second boost converters are controlled so that the voltage of the second power line becomes the target voltage and the required power is output to the second power line.

JP-A-2010-104139

In the above-mentioned boost converter device, generally, when the temperature of one of the first and second boost converters is equal to or higher than the upper limit temperature, the output of the boost converter whose temperature is equal to or higher than the upper limit temperature is limited (smaller), and the temperature becomes the upper limit temperature. By increasing the output of the boost converter of less than or equal to less than, and concentrating the load, the further rise of the boost converter whose temperature is equal to or higher than the upper limit temperature is suppressed while suppressing the decrease of the power supplied to the electric load. However, when the output of the electric load transiently increases, the output of the boost converter whose temperature is below the upper limit temperature suddenly increases, the load concentrates and the temperature rises, and the temperatures of both the first and second boost converters exceed the upper limit temperature. May become.

The main purpose of the boost converter device of the present invention is to suppress the concentration of load on one of the first and second boost converters.

The boost converter device of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The boost converter device of the present invention
A first boost converter that exchanges power with voltage conversion between the first power line connected to the power storage device and the second power line connected to the electric load.
A second boost converter that is connected in parallel to the first boost converter and exchanges power between the first power line and the second power line with voltage conversion.
A control device that controls the first and second boost converters so that the voltage of the second power line becomes the target voltage, and
It is a boost converter device equipped with
The control device is
The smaller value of the first limit factor for limiting the output of the first boost converter and the second limit rate for limiting the output of the second boost converter is set as the output limit rate.
The first current obtained by multiplying the target current based on the required power of the electric load and the target voltage by the first distribution ratio, which is the ratio of the current output from the first boost converter to the target current, and the first current. The current obtained by multiplying the output limit rate and the smaller current is output from the first boost converter, and the target current is multiplied by the second distribution rate obtained by subtracting the first distribution rate from the value 1. The first and second boost converters are controlled so that the smaller current of the second current and the current obtained by multiplying the second current by the output limit factor is output from the second boost converter. ,
The gist is that.

In the boost converter device of the present invention, the smaller value of the first limiting factor for limiting the output of the first boost converter and the second limiting factor for limiting the output of the second boost converter is output limited. Set to rate. Then, the first current obtained by multiplying the target current based on the required power of the electric load and the target voltage by the first distribution ratio, which is the ratio of the current output from the first boost converter among the target currents, and the first current are output. The current obtained by multiplying the limit rate and the smaller current are output from the first boost converter, and the second current obtained by multiplying the target current by the second distribution rate obtained by subtracting the first distribution rate from the value 1 and the second current. The first and second boost converters are controlled so that the current obtained by multiplying the two currents by the output limiting rate and the smaller current is output from the second boost converter. Here, the "first limit rate", the "second limit rate", and the "output limit rate" are set to a value of 0 or more and a value of 1 or less. As a result, it is possible to prevent the load from being concentrated on one of the first and second boost converters.

In such a boost converter device of the present invention, when the control device does not limit the outputs of both the first and second boost converters, the voltage of the second power line becomes the target voltage and the first current. Is output from the first boost converter, and the first and second boost converters are controlled so that the second current is output from the second boost converter, among the first and second boost converters. When limiting at least one output, the smaller of the first current and the current obtained by multiplying the first current by the output limiting factor is output from the first boost converter, and the second boost converter outputs the current. The first and second boost converters are controlled so that the smaller current of the current and the current obtained by multiplying the second current by the output limit factor is output from the second boost converter. May be good. In this way, when the output of at least one of the first and second boost converters is limited, it is possible to prevent the load from being concentrated on any of the boost converters.

The motor device of the present invention
The boost converter device of the present invention in any of the above-described embodiments, that is, basically, the conversion of voltage between the first power line connected to the power storage device and the second power line connected to the electric load. A first booster converter that exchanges power with the transfer of power and a first booster converter that is connected in parallel to the first booster converter and exchanges power with voltage conversion between the first power line and the second power line. A boost converter device including a two boost converter and a control device that controls the first and second boost converters so that the voltage of the second power line becomes a target voltage. The control device is the first boost converter. The smaller value of the first limiting factor for limiting the output of the 1 boosting converter and the second limiting factor for limiting the output of the second boosting converter is set as the output limiting factor, and the electric load of the electric load is set. The first current obtained by multiplying the target current based on the required power and the target voltage by the first distribution rate, which is the ratio of the currents output from the first booster converter among the target currents, and the first current multiplied by the output limit. The current obtained by multiplying the rate and the smaller current are output from the first boost converter, and the target current is multiplied by the second distribution rate obtained by subtracting the first distribution rate from the value 1 to obtain the second current. A boost converter device that controls the first and second boost converters so that the second current multiplied by the output limit factor and the smaller current is output from the second boost converter. ,
The motor as the electric load and
A motor control device that controls the motor and
It is a motor device equipped with
The motor control device controls the motor so that the smaller of the required torque required for the motor and the torque obtained by multiplying the required torque by the output limit factor is output.
The gist is that.

Since the motor device of the present invention includes the boost converter device of the present invention in any of the above-described aspects, the effect exerted by the boost converter device of the present invention, that is, a load on one of the first and second boost converters. Can produce the same effect as the effect that can suppress the concentration of.

It is a block diagram which shows the outline of the structure of the electric vehicle 20 which mounted the boost converter device as one Example of this invention. It is a block diagram which shows the outline of the structure of the electric drive system including a motor 32. It is a flowchart which shows an example of the limit rate setting processing routine executed by ECU 70. Temperatures of the first and second boost converters 40 and 41 ct1, tk2 and output limit factors α and β, load factor Rm of the motor 32, time of output (power) of the motor 32 and the first and second boost converters 40 and 41 It is explanatory drawing which shows an example of the change.

Next, a mode for carrying out the present invention will be described with reference to examples.

FIG. 1 is a configuration diagram showing an outline of the configuration of an electric vehicle 20 equipped with a boost converter device as an embodiment of the present invention. FIG. 2 is a configuration diagram showing an outline of the configuration of the electric drive system including the motor 32. As shown in FIG. 1, the electric vehicle 20 of the embodiment includes a motor 32, an inverter 34, a battery 36 as a power storage device, first and second boost converters 40 and 41, and an electronic control unit 70. Be prepared. Here, the boost converter device of the embodiment mainly corresponds to the first and second boost converters 40 and 41 and the electronic control unit (hereinafter referred to as “ECU”) 70.

The motor 32 is configured as, for example, a synchronous generator motor, and the rotor is connected to a drive shaft 26 connected to the drive wheels 22a and 22b via a differential gear 24. The inverter 34 is connected to the motor 32 and also to the high voltage side power line 42. The motor 32 is rotationally driven by switching control of a plurality of switching elements (not shown) of the inverter 34 by the ECU 70. A smoothing capacitor 46 is attached to the positive electrode side line and the negative electrode side line of the high voltage side power line 42.

The battery 36 is configured as, for example, a lithium ion secondary battery or a nickel hydrogen secondary battery, and is connected to the low voltage side power line 44. A smoothing capacitor 48 is attached to the positive electrode side line and the negative electrode side line of the low voltage side power line 44.

The first and second boost converters 40 and 41 are connected in parallel to the high voltage side power line 42 and the low voltage side power line 44. As shown in FIG. 2, the first boost converter 40 has two transistors T11 and T12, two diodes D11 and D12 connected in parallel to each of the two transistors T11 and T12, and a reactor L1. .. The transistor T11 is connected to the positive electrode side line of the high voltage side power line 42. The transistor T12 is connected to the transistor T11 and the negative electrode side line of the high voltage side power line 42 and the low voltage side power line 44. The reactor L1 is connected to a connection point between the transistors T11 and T12 and a positive electrode side line of the low voltage side power line 44. The first boost converter 40 boosts the power of the low voltage side power line 44 and supplies it to the high voltage side power line 42 by adjusting the ratio of the on-time of the transistors T11 and T12 by the ECU 70. The power of the voltage side power line 42 is stepped down and supplied to the low voltage side power line 44. Like the first boost converter 40, the second boost converter 41 has two transistors T21 and T22, two diodes D21 and D22, and a reactor L2. The second boost converter 41 boosts the power of the low voltage side power line 44 and supplies it to the high voltage side power line 42 by adjusting the ratio of the on-time of the transistors T21 and T22 by the ECU 70. The power of the high voltage side power line 42 is stepped down and supplied to the low voltage side power line 44.

Although not shown, the ECU 70 is configured as a microprocessor centered on a CPU, and in addition to the CPU, a ROM for storing a processing program, a RAM for temporarily storing data, a non-volatile flash memory, and an input / output port. To be equipped. As shown in FIG. 1, signals from various sensors are input to the ECU 70 via input ports. The signals input to the ECU 70 include, for example, the rotation position θm from the rotation position detection sensor 32a that detects the rotation position of the rotor of the motor 32, and the phase from the current sensor that detects the current flowing through each phase of the motor 32. Currents Iu and Iv can be mentioned. Further, the voltage Vb from the voltage sensor attached between the terminals of the battery 36 and the current Ib from the current sensor attached to the output terminal of the battery 36 can also be mentioned. Further, the voltage VH of the high voltage side power line 42 (capacitor 46) from the voltage sensor 46a attached between the terminals of the capacitor 46 and the low voltage side power line from the voltage sensor 48a attached between the terminals of the capacitor 48. The voltage VL of 44 (capacitor 48) can also be mentioned. Reactor currents IL1 and IL2 from current sensors 40a and 41a that detect the current flowing through the reactors L1 and L2 of the first and second boost converters 40 and 41 (the direction of the current from the battery 36 side toward the transistors T11 and T21 is positive. (Value) and the temperatures ct1 and tk2 of the first and second boost converters 40 and 41 from the temperature sensors 40b and 41b attached to the first and second boost converters 40 and 41 can also be mentioned. Examples include the ignition signal from the ignition switch 80 and the shift position SP from the shift position sensor 82 that detects the operating position of the shift lever 81. Further, the accelerator opening degree Acc from the accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal 83 and the brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal 85 can be mentioned. Further, the vehicle speed V from the vehicle speed sensor 88 can also be mentioned.

Various control signals are output from the ECU 70 via the output port. The signals output from the ECU 70 include, for example, a switching control signal for a plurality of switching elements of the inverter 34, a switching control signal for the transistors T11 and T12 of the first boost converter 40, and a transistor T21 of the second boost converter 41. A switching control signal to T22 can be mentioned. The ECU 70 calculates the electric angle θe and the rotation speed Nm of the motor 32 based on the rotation position θm of the rotor of the motor 32 from the rotation position detection sensor 32a. Further, the ECU 70 calculates the storage ratio SOC of the battery 36 based on the cumulative value of the current Ib of the battery 36 from the current sensor, and is detected by the calculated storage ratio SOC and a temperature sensor (not shown) attached to the battery 36. Based on the battery temperature Tb, the input / output limit rates Win and Wout, which are the maximum allowable powers that may charge and discharge the battery 36, are calculated. Here, the storage ratio SOC is the ratio of the capacity of electric power that can be discharged from the battery 36 to the total capacity of the battery 36.

In the electric vehicle 20 of the embodiment configured in this way, the ECU 70 first sets the required torque Td * required for traveling (required for the drive shaft 26) based on the accelerator opening degree Acc and the vehicle speed V. The smaller value of the set required torque Td * and the required torque Td * multiplied by the load factor Rm (= Td * × Rm) is set in the torque command Tm * of the motor 32, and the motor 32 sets the torque command. Switching control of a plurality of switching elements of the inverter 34 is performed so as to be driven by Tm *. The load factor Rm is the ratio of the required torque Td * to the torque that can be output from the motor 32, and is set to a value of 0 or more and a value of 1 or less. For example, from the viewpoint of protecting the motor 32, the load factor Rm is set to a smaller value when the temperature of the motor 32 is equal to or higher than the predetermined temperature Tmref, as compared with when the temperature of the motor 32 is high, that is, when the temperature of the motor 32 is low. The higher the temperature, the smaller the value. The predetermined temperature Tmref is a threshold value for determining whether or not the motor 32 is at a high temperature, and is set to, for example, 80 ° C., 90 ° C., 100 ° C., or the like.

The ECU 70 sets the target voltage VH * of the high voltage side power line 42 required to drive the motor 32 at the target operating point consisting of the torque command Tm * of the motor 32 and the rotation speed Nm. Then, the required output Pm * of the motor 32 is set by multiplying the torque command Tm * of the motor 32 by the rotation speed Nm, and the voltage VH and the target voltage VH * of the high voltage side power line 42 and the required output Pm * of the motor 32 are combined. The total target current IL * of the first and second boost converters 40 and 41 is set based on the above. Then, of the value obtained by multiplying the target current IL * by the distribution rates Dr1 and Dr2 (Dr1 + Dr2 = 1) and the value obtained by multiplying the target current IL * by the distribution rates Dr1 and Dr2 and the output limiting rates α and β. The smaller value is set to the target currents IL1 * and IL2 * of the reactors L1 and L2. Here, the distribution ratios Dr1 and Dr2 are the low-voltage side power line 44 and the high-voltage side power line 42 via the first and second boost converters 40 and 41 (reactors L1 and L2) of the total target current IL *, respectively. It is the ratio of the current flowing between and. The distribution rate Dr1 can be a predetermined value Drf (for example, 0.4, 0.5, 0.6, etc.). The output limiting rates α and β are the ratios of the currents that are allowed to be output from the first and second boost converters 40 and 41 among the currents obtained by multiplying the total target current IL * by the distribution rates Dr1 and Dr2 (Dr1 + Dr2 = 1). It is set to a value of 0 or more and a value of 1 or less. The output limit rate α is set to a value 1 when the temperature ct1 of the first boost converter 40 is less than the predetermined temperature tmref, and the temperature tk1 is high when the temperature ct1 of the first boost converter 40 is equal to or higher than the predetermined temperature tmref. Sometimes it is set to be smaller than when it is low, that is, it is set to be smaller as the temperature ct1 is higher. The output limit rate β is set to a value 1 when the temperature ct2 of the second boost converter 41 is less than the predetermined temperature tmref, and is high when the temperature ct2 of the second boost converter 41 is equal to or higher than the predetermined temperature tmref. Sometimes it is set to be smaller than when it is low, that is, it is set to be smaller as the temperature tk2 is higher. When the target currents IL1 * and IL2 * of the reactors L1 and L2 of the first and second boost converters 40 and 41 are set in this way, the currents IL1 and IL2 of the transistors L1 and L2 of the first and second boost converters 40 and 41 are targeted. Switching control of the transistors T11, T12, T21, and T22 of the first and second boost converters 40 and 41 is performed so that the currents are IL1 * and IL2 *. As a result, the electric power from the battery 36 is supplied to the motor 32 via the inverter 34 with voltage conversion.

Next, the operation of the electric vehicle 20 configured in this way, particularly the operation when limiting (reducing) the output of at least one of the first and second boost converters 40 and 41 will be described. FIG. 3 is a flowchart showing an example of a limit rate setting processing routine executed by the ECU 70. This routine is repeatedly executed every predetermined time (for example, every several msec) when the temperatures ct1 and tk2 of the first and second boost converters 40 and 41 are equal to or higher than the predetermined temperature tmref.

When this routine is executed, the CPU of the ECU 70 sets the output limit factor α using the temperature ct1 of the first boost converter 40 (step S100) and sets the temperature ct2 of the second boost converter 41 as described above. The output limit rate β is set by using (step S110).

Subsequently, the smaller value of the set output limit factors α and β is set in the converter limit factor γ (step S120). When the converter limiting rate γ is set in this way, the ECU 70 distributes the target current IL * by the distribution rates Dr1 and Dr2 and the target current IL * in the control of the first and second boost converters 40 and 41 described above. The smaller value of the value obtained by multiplying the rates Dr1 and Dr2 and the converter limit factor γ is set to the target currents IL1 * and IL2 * of the transistors L1 and L2, and the first and second boost converters 40 and 41 are set. Switching control of the transistors T11, T12, T21, and T22 of the first and second boost converters 40 and 41 is performed so that the currents IL1 and IL2 of the reactors L1 and L2 become the target currents IL1 * and IL2 *. When the outputs of the first and second boost converters 40 and 41 are limited by using the output limit factors α and β, the output of the larger boost converter of the output limit factors α and β becomes larger (load is concentrated). Therefore, when the rotation speed Nm of the motor 32 is transiently increased due to slip or the like and the load of the motor 32 is increased, the output of the boost converter, which is the larger of the output limiting factors α and β, becomes larger (the load is concentrated). , May get hot. In the embodiment, both the outputs of the first and second boost converters 40 and 41 are limited by using the converter limit γ which is the smaller value of the output limit α and β, so that the first and second boost converters are boosted first and second. Both the outputs of the converters 40 and 41 can be limited (reduced). As a result, it is possible to prevent the load from being concentrated on one of the first and second boost converters 40 and 41.

Subsequently, the converter limit factor γ is set to the load factor Rm of the motor 32 (step S130), and this routine is terminated. When the load factor Rm is set in this way, the ECU 70 sets the torque command Tm * using the load factor Rm (= γ) set as described above, and the inverter drives the motor 32 with the set torque command Tm *. It controls a plurality of switching elements of 34. If the smaller value of the output limiting factors α and β is set to the converter limiting factor γ in step S120, both the outputs of the first and second boost converters 40 and 41 are limited by using the converter limiting factor γ. The torque that can be output from the motor 32 decreases. By setting the converter limit factor γ to the load factor Rm of the motor 32 and setting the torque command Tm2 * using the load factor Rm (= γ), the output of the first and second boost converters 40 and 41 can be reduced. The output of the motor 32 can be reduced accordingly. Therefore, the motor 32 can be controlled more appropriately.

FIG. 4 shows the temperatures ct1 and tk2 of the first and second boost converters 40 and 41, the output limiting factors α and β, the load factor Rm of the motor 32, and the outputs of the motor 32 and the first and second boost converters 40 and 41 ( It is explanatory drawing which shows an example of time change of (electric power). When the temperature tc1 becomes equal to or higher than the predetermined temperature tmref (time t1), the output limit rate α decreases from the value 1 as shown in the figure. When the output limit rate α decreases from the value 1, the converter limit rate γ is set to the output limit rate α and decreases from the value 1. The load factor Rm of the motor 32 also decreases from the value 1. As the converter limit factor γ and the load factor Rm decrease, the output of the motor 32 and the outputs of the first and second boost converters 40 and 41 decrease. In this way, when the temperature tc1 becomes equal to or higher than the predetermined temperature tmref and the output limiting factor α decreases from the value 1, that is, when the output of the first boost converter 40 is limited, the first and second boost converters 40 and 41 Both outputs are limited. As a result, it is possible to suppress the concentration of the load (output) on one of the first and second boost converters 40 and 41, and it is possible to prevent both the first and second boost converters 40 and 41 from becoming hot.

According to the step-up converter device mounted on the electric vehicle 20 of the above-described embodiment, the smaller value of the limiting factors α and β is set to the converter output limiting factor γ, and the distribution rate Dr1 is set to the target current IL *. The smaller current of the multiplied current and the current obtained by multiplying the target current IL * by the distribution rate Dr1 and the converter output limit rate γ is output from the first boost converter 40, and the target current IL * is multiplied by the distribution rate Dr2. The first and first so that the smaller current of the current multiplied by and the current obtained by multiplying the target current IL * by the distribution rate Dr2 and the converter output limiting factor γ is output from the second boost converter 41 By controlling the two boost converters 40 and 41, it is possible to suppress the concentration of the load (output) on one of the first and second boost converters 40 and 41.

In the boost converter device mounted on the electric vehicle 20 of the embodiment, the output limiting factors α and β are set by comparing the temperatures ct1 and tk2 of the first boost converters 40 and 41 with the predetermined temperature tmref. However, the temperatures ct1 and tk2 of the first boost converters 40 and 41 may be compared with different temperatures. The temperature tc2 may be compared with a temperature different from the predetermined temperature tmref.

In the boost converter device mounted on the electric vehicle 20 of the embodiment, when at least one of the temperatures ct1 and tk2 of the first and second boost converters 40 and 41 is equal to or higher than the predetermined temperature tmref, the limitation illustrated in FIG. The rate setting processing routine is being executed. However, the execution condition of the limit rate setting processing routine is not limited to the case where at least one of the temperatures ct1 and tk2 of the first and second boost converters 40 and 41 is equal to or higher than the predetermined temperature tmref, and the first one. It may be another condition that can determine that at least one output of the second boost converters 40 and 41 should be limited.

In the boost converter device mounted on the electric vehicle 20 of the embodiment, when at least one of the temperatures ct1 and tk2 of the first and second boost converters 40 and 41 is equal to or higher than the predetermined temperature tmref, the limitation illustrated in FIG. The rate setting processing routine is being executed. However, regardless of whether or not at least one output of the first and second boost converters 40 and 41 should be limited, the limit rate setting illustrated in FIG. 3 is set when driving the first and second boost converters 40 and 41. The processing routine may be executed at all times. In this case, in the control of the first and second boost converters 40 and 41, the value obtained by multiplying the target current IL * by the distribution rates Dr1 and Dr2 and the target current IL * are divided into the distribution rates Dr1 and Dr2 and the converter limiting rate γ. The smaller of the multiplied values is set to the target currents IL1 * and IL2 * of the reactors L1 and L2, and the currents IL1 and IL2 of the reactors L1 and L2 of the first and second boost converters 40 and 41 are set. Switching control of the transistors T11, T12, T21, and T22 of the first and second boost converters 40 and 41 may be performed so that the target currents are IL1 * and IL2 *.

The boost converter device mounted on the electric vehicle 20 of the embodiment includes the battery 36 as the power storage device, but a capacitor may be used instead of the battery 36.

In the embodiment, the boost converter device mounted on the electric vehicle 20 equipped with the inverter 34 and the motor 32 as the electric load is used. However, the form of the boost converter device mounted on the electric vehicle 20 is not limited to two boosters connected in parallel, in which power is exchanged between the electric load and the power storage device with voltage conversion. Any form may be used as long as it is a boost converter device including a converter.

The correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem will be described. In the embodiment, the inverter 34 and the motor 32 correspond to the "electric load", the battery 36 corresponds to the "storage device", the first boost converter 40 corresponds to the "first boost converter", and the second boost converter 41. Corresponds to the "second boost converter", and the electronic control unit 70 corresponds to the "control device".

Regarding the correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem, the invention described in the column of means for solving the problem in the examples is carried out. Since it is an example for specifically explaining the form for solving the problem, the elements of the invention described in the column of means for solving the problem are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be performed based on the description in the column, and the examples are the inventions described in the column of means for solving the problem. It is just a concrete example.

Although the embodiments for carrying out the present invention have been described above with reference to examples, the present invention is not limited to these examples, and various embodiments are used without departing from the gist of the present invention. Of course, it can be done.

The present invention can be used in the manufacturing industry of boost converter devices and the like.

20 electric vehicle, 22a, 22b drive wheel, 24 differential gear, 26 drive shaft, 32 motor, 32a rotation position detection sensor, 34 inverter, 36 battery, 40 first boost converter, 40a, 41a current sensor, 40b, 41b temperature sensor , 41 2nd boost converter, 42 high voltage side power line, 44 low voltage side power line, 46,48 condenser, 46a, 48a voltage sensor, 70 electronic control unit (ECU), 80 ignition switch, 81 shift lever, 82 shift Position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed sensor, D11, D12, D21, D22 diode, L1, L2 reactor, T11, T12, T21, T22 transistor.

Claims (1)

A first boost converter that exchanges power with voltage conversion between the first power line connected to the power storage device and the second power line connected to the electric load.
A second boost converter that is connected in parallel to the first boost converter and exchanges power between the first power line and the second power line with voltage conversion.
A control device that controls the first and second boost converters so that the voltage of the second power line becomes the target voltage, and
It is a boost converter device equipped with
The control device is
The smaller value of the first limit factor for limiting the output of the first boost converter and the second limit rate for limiting the output of the second boost converter is set as the output limit rate.
The first current obtained by multiplying the target current based on the required power of the electric load and the target voltage by the first distribution ratio, which is the ratio of the current output from the first boost converter to the target current, and the first current. The current obtained by multiplying the output limit factor and the smaller current is output from the first boost converter, and the target current is multiplied by the second distribution rate obtained by subtracting the first distribution rate from the value 1. The first and second boost converters are controlled so that the smaller current of the two currents and the current obtained by multiplying the second current by the output limit factor is output from the second boost converter.
Boost converter device.

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