JP2017225227A - Power supply device and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device and computer program capable of reducing a temperature difference between phases in a multiphase configured voltage converter circuit.SOLUTION: A power supply device includes: inductors L1 and L2; voltage converter circuits 1a, 1a having transistors Q1 and Q2 for switching currents respectively flowing the inductors L1 and L2; and a controller 10a for turning on/off the transistors Q1 and Q2 with different phase, and the output of the voltage converters 1a and 1a are connected in parallel. The voltage converter circuits 1a, 1a include temperature sensors Ts1 and Ts2 for respectively detecting temperatures of the transistors Q1 and Q2 or ambient temperature, and the controller 10a calculates an amount of compensation for compensating a duty ratio of turning on/off the transistors Q1 and Q2 respectively corresponding to the temperature sensors Ts1 and Ts2, on the basis of temporal series of detection results of the temperature sensors Ts1 and Ts2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power supply apparatus and a computer program in which a plurality of voltage conversion circuits that perform voltage conversion by switching a DC voltage or an AC voltage with a switching element are connected in parallel.

  Converters or inverters (hereinafter referred to as converters including inverters) that convert a DC voltage or an AC voltage into a desired voltage by stepping up and down are used in various fields. The converter outputs a required voltage by periodically switching the current flowing through the inductor with a switching element. In order to increase the output current, reduce the ripple of the output current, and reduce the size of the device, a multi-phase converter in which a plurality of converters are operated in different phases and connected in parallel is used. Yes.

  For example, in Patent Document 1, the individual output currents of the respective DC / DC converters are added even if the balance of the current limitation of the individual DC / DC converters is lost due to variations in characteristics of circuit elements and changes in characteristics due to temperature. A multi-phase DC / DC converter that limits the output current of each DC / DC converter so as not to exceed a predetermined total current is disclosed. Further, Patent Document 2 discloses a multi-phase converter in which a plurality of converter circuits are connected in parallel so as to have different output phases, and these converter circuits are driven, and the outputs are added to form one output. ing.

  In the multiphase DC / DC converter described in Patent Document 1 or 2, for example, when there is a temporary fluctuation in control of each converter and current is concentrated in a specific DC / DC converter, heat loss in a specific switching element May increase and reliability may deteriorate, or deterioration or burnout may occur.

  In contrast, the multiphase converter described in Patent Document 3 outputs a current that outputs a control signal common to n sub-circuits based on a current control command and a phase current value of one sub-circuit (one converter). And a balance controller that controls the duty ratio of the control signal for each phase sub-circuit based on the phase current value of each phase sub-circuit and the control signal from the current controller. As a result, for example, when the output voltage is constant, the current of each phase is balanced, and a bias of heat loss in each phase converter is prevented.

JP 2003-284333 A JP 2008-141802 A Japanese Patent Laying-Open No. 2015-220976

  However, according to the technique disclosed in Patent Document 3, even if the heat loss in each converter is constant, the thermal resistance of the heat dissipation member and the like included in each converter is not necessarily constant. As a result, there is a problem that certain converters may be hotter than other converters.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a power supply device and a computer program capable of reducing a temperature difference between phases in a voltage conversion circuit having a multiphase configuration. There is to do.

  A power supply device according to an aspect of the present invention includes a plurality of voltage conversion circuits including an inductor and a switching element that switches a current flowing through the inductor, and a control unit that turns each switching element on and off in a different phase. A power supply apparatus in which outputs of voltage conversion circuits are connected in parallel, each voltage conversion circuit having a temperature sensor for detecting a temperature of each switching element or an ambient temperature, and the control unit includes each temperature sensor Based on these time-series detection results, a correction amount for correcting the duty ratio for turning on / off the switching element corresponding to each temperature sensor is calculated.

  A computer program according to one embodiment of the present invention includes an inductor, a switching element that switches a current that flows through the inductor, a plurality of voltage conversion circuits that include a temperature sensor that detects a temperature of the switching element or an ambient temperature, and each A computer program that can be executed by the control unit in a power supply device that includes a control unit that turns on and off switching elements at different phases and that has outputs of each voltage conversion circuit connected in parallel. A step of acquiring the detection results of the temperature sensors in time series, a step of calculating a correction amount for correcting a duty ratio for turning on / off the switching element corresponding to each temperature sensor based on the acquired detection results; And a step of correcting the duty ratio based on the calculated correction amount.

  In addition, this application can implement | achieve a power supply device provided with such a characteristic process part, or can implement | achieve as a computer program for making a control part perform the step corresponding to this characteristic process part. Instead, it can be realized as a driving method of the voltage conversion circuit including such steps. Further, a part or all of the power supply device can be realized as a semiconductor integrated circuit, or can be realized as another system including the power supply device.

  According to the above, it is possible to reduce the temperature difference between the phases in the voltage conversion circuit having a multiphase configuration.

1 is a block diagram illustrating a configuration example of a power supply device according to a first embodiment. It is a block diagram which shows the function structure of the control part which feedback-controls an output voltage. It is a block diagram which shows the function structure of the control part which feedback-controls the temperature which concerns on the transistor of a 1st phase. 3 is a flowchart illustrating a processing procedure of a CPU that calculates a correction amount of a duty ratio of each phase and calculates a phase at which a PWM signal is turned on / off in the power supply device according to the first embodiment. FIG. 6 is a block diagram illustrating a configuration example of a power supply device according to a second embodiment. FIG. 6 is a block diagram illustrating a configuration example of a power supply device according to a third embodiment. FIG. 6 is a block diagram illustrating a configuration example of a power supply device according to a fourth embodiment. 10 is a flowchart illustrating a processing procedure of a CPU that calculates a correction amount of a duty ratio of each phase and calculates a phase at which a PWM signal is turned on / off in the power supply device according to the fourth embodiment.

[Description of Embodiment of the Present Invention]
First, embodiments of the present invention will be listed and described. Moreover, you may combine arbitrarily at least one part of embodiment described below.

(1) A power supply device according to an aspect of the present invention includes an inductor, a plurality of voltage conversion circuits including a switching element that switches a current flowing through the inductor, and a control unit that turns on / off each switching element in different phases. Each voltage conversion circuit has a temperature sensor that detects the temperature or ambient temperature of each switching element, and the control unit includes: Based on the time-series detection result of each temperature sensor, a correction amount for correcting the duty ratio for turning on / off the switching element corresponding to each temperature sensor is calculated.

In this aspect, the control unit turns on / off the switching elements of each of the plurality of voltage conversion circuits at different phases, and switches the currents flowing through the respective inductors by the switching elements, thereby inputting each voltage conversion circuit. The converted voltages are converted and output in parallel. The control unit further turns on / off each switching element based on the temperature detected by each temperature sensor in time series with respect to the temperature of each switching element or the ambient temperature (hereinafter referred to as temperature related to the switching element). A correction amount for correcting the ratio is calculated separately.
Accordingly, the duty ratio for turning on / off the switching element having a relatively high temperature (or low) is corrected so as to be small (or large).

(2) It is preferable that the control unit calculates the correction amount based on a deviation of a detection result of each temperature sensor with respect to a representative value of a detection result of each temperature sensor.

In this aspect, the representative value of the detection result of the temperature related to each switching element is calculated, the deviation of the detection result of the temperature related to each switching element with respect to the calculated representative value is further calculated, and each calculated deviation is calculated. Based on this, a correction amount for correcting the duty ratio for turning on / off each switching element is calculated.
As a result, the duty ratio for turning on / off the switching element in which the deviation of the temperature detection result is negative (or positive) with respect to the representative value of the temperature detection result is small (or large) according to the absolute value of the deviation. It is corrected so that

(3) It is preferable that the control unit calculates the correction amount by PI control or PID control using the temperature or ambient temperature of each switching element as a control amount and the representative value as a target value.

In this embodiment, PI control or PID control in which the temperature related to each switching element is a controlled variable, and the representative value of the temperature detection result related to each switching element is the target value, the number of voltage conversion circuits, that is, switching By performing in parallel the number of elements, a duty ratio correction amount is calculated as an operation amount for each switching element.
Thereby, the offset which arises in the temperature concerning each switching element is reduced.

(4) Each voltage conversion circuit further includes a current sensor that detects a current flowing through each inductor, and the control unit determines whether the detection result of each current sensor is greater than a predetermined threshold value. It is preferable to reduce the duty ratio for turning on / off the switching element corresponding to the determined current sensor.

In this aspect, when the current flowing through each of the plurality of inductors is larger than the threshold, the duty ratio for turning on / off the switching element corresponding to the inductor in which the current larger than the threshold is detected is reduced.
This prevents the switching element from being deteriorated or damaged at a high temperature.

(5) A computer program according to an aspect of the present invention includes a plurality of voltage conversion circuits including an inductor, a switching element that switches a current flowing through the inductor, and a temperature sensor that detects a temperature of the switching element or an ambient temperature. And a computer program that can be executed by the control unit in a power supply device that includes a control unit that turns on / off each switching element at a different phase, and that connects outputs of the voltage conversion circuits in parallel. In addition, a step of acquiring the detection results of each temperature sensor in time series, and a correction amount for correcting the duty ratio for turning on / off the switching element corresponding to each temperature sensor is calculated based on the acquired detection results. And a step of correcting the duty ratio based on the calculated correction amount. .

In this aspect, the step of acquiring the detection results of each temperature sensor in time series to the computer that executes the computer program in the control unit, and the corresponding switching element is turned on based on each acquired detection result. A step of calculating a correction amount for correcting the duty ratio to be turned off and a step of correcting the corresponding duty ratio based on each calculated correction amount are executed.
Accordingly, the duty ratio for turning on / off the switching element having a relatively high temperature (or low) is corrected so as to be small (or large).

[Details of the embodiment of the present invention]
A specific example of the power supply device according to the embodiment of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes within the meaning and range equivalent to a claim are included. In addition, the technical features described in each embodiment can be combined with each other.

(Embodiment 1)
FIG. 1 is a block diagram illustrating a configuration example of a power supply device according to the first embodiment. In the figure, reference numeral 1a denotes a voltage conversion circuit that boosts a voltage from an external power supply 2 and supplies the boosted voltage to an external load 3. The power supply apparatus includes voltage conversion circuits 1a and 1a and the voltage conversion circuits 1a and 1a. And a control unit 10a for controlling the conversion. The number of voltage conversion circuits 1a should just be two or more, and is not limited to two.

  The voltage conversion circuit 1a includes an inductor L1 (or L2) and an N-channel MOSFET (Metal Oxide Field Effect Transistor) which is a switching element that switches a current flowing from the power source 2 to the inductor L1 (or L2). ) Q1 (or Q2) and a temperature sensor Ts1 (or Ts2) for detecting the temperature or ambient temperature of the transistor Q1 (or Q2) (hereinafter also referred to as a temperature related to the transistor Qi (i is a natural number)). The transistors Q1 and Q2 are not limited to MOSFETs, and may be other switching elements such as bipolar transistors and IGBTs (Insulated Gate Bipolar Transistors).

  The connection point between the inductors L1 and L2 and the drains of the transistors Q1 and Q2 is connected to the anodes of the diodes D1 and D2. The sources of the transistors Q1 and Q2 are connected to the ground potential. The voltages converted by the voltage conversion circuits 1a and 1a are output in parallel from the cathodes of the diodes D1 and D2 and smoothed by the capacitor C1, and are divided by the voltage dividing circuit of the resistors R1 and R2 to be controlled by the control unit 10a. Given to.

  The temperature sensors Ts1 and Ts2 are, for example, thermistors or thermocouples, but may be replaced with other sensors as long as they can detect the temperature and output the detection voltage. Each of the temperature sensors Ts1 and Ts2 is preferably in close contact with the case or the heat sink of the transistors Q1 and Q2 to detect the temperature as close as possible to the channel temperature, but it detects the ambient temperature rising due to the heat from the transistors Q1 and Q2. May be.

  The control unit 10a includes a central processing unit (CPU) 11 serving as a center for controlling the transistors Q1 and Q2, and a non-volatile memory such as a flash memory, an EPROM (Erasable Programmable Read Only Memory), and an EEPROM (Electrically EPROM). A ROM 12 used, a RAM 13 using a rewritable memory such as a DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), and the like, and a timer 14 for measuring time are provided. The CPU 11, the ROM 12, the RAM 13, and the timer 14 are connected to each other via a bus.

  The control unit 10a further generates drive signals for turning on / off the transistors Q1 and Q2 and applies them to the gates, detection voltages of the temperature sensors Ts1 and Ts2, and resistors R1 and R2. An A / D converter 19 that performs A / D conversion on the divided voltage is provided, all of which are bus-connected to the CPU 11. The drive signal is, for example, a PWM (Pulse Width Modulation) signal, but may be any other signal as long as the ratio of the on time to the total on / off time, that is, the duty ratio is defined.

  The CPU 11 controls the operation of each unit connected by the bus according to a control program stored in advance in the ROM 12 and performs processing such as calculation, and the driving circuits 15 and 15 turn the transistors Q1 and Q2 on and off at different phases. The RAM 13 temporarily stores information generated by the processing by the CPU 11. A computer program that defines the procedure of each process performed by the CPU 11 may be loaded in advance into the RAM 13 using means (not shown), and the computer program may be executed by the CPU 11. You may comprise with a hardware circuit for exclusive use.

Next, the functional configuration of the control unit 10a will be described. In the following description, it is assumed that the power supply device includes N voltage conversion circuits 1a (N is a natural number of 2 or more). The blocks related to the N voltage conversion circuits 1a, 1a,... 1a are identified as the first phase, the second phase,.
FIG. 2 is a block diagram illustrating a functional configuration of the control unit 10a that performs feedback control of the output voltage, and FIG. 3 is a block diagram illustrating a functional configuration of the control unit 10a that performs feedback control of the temperature related to the first-phase transistor Q1. It is. The inside of the frame shown by the broken line in FIG. 2 and FIG. 3 is the control unit 10a, and among the blocks in the frame, those not marked are blocks realized by the CPU 11. The block represented by the symbol “Σ” in the circle is an adder.

  In FIG. 2, each of the N drive circuits 15, 15,... 15 is connected to a different voltage conversion circuit 1a. The signals output from the drive circuits 15, 15,... 15 are PWM signals as described above. The output voltage from the voltage conversion circuits 1a, 1a,... 1a is the control amount of the feedback control here. The output voltage is divided by a voltage dividing circuit composed of resistors R1 and R2, and converted into a digital value by an A / D converter 19 to become a feedback voltage.

  The CPU 11 uses a target voltage acquired from an external interface (not shown) or a target voltage set by its own processing as a target value, and follows the target value based on the deviation of the feedback voltage with respect to the target value (PI (Proportional Integral)). Take control. The PI control may be other feedback control such as PID (Proportional Integral Derivative) control. Here, the operation amount generated by the PI control is a typical duty ratio for the drive circuits 15, 15,.

  The generated representative duty ratio is given to N adders in parallel. The N adders correspond to each phase from the first phase to the Nth phase, and add a representative duty ratio and a correction amount from the first phase to the Nth phase, which will be described later, separately. To do. Each of the N duty ratios generated by the addition is supplied to different drive circuits 15. The PWM signals generated by the drive circuits 15, 15,... 15 are different in phase by 2π / N.

  3, each of the N voltage conversion circuits 1a, 1a,... 1a has a different temperature sensor Tsj (j is one of 1 to N). Each Tsj detects a temperature related to a transistor Qj (not shown in FIG. 3). The detection voltages of the temperature sensors Ts1, Ts2,... TsN are converted by the A / D converter 19 and added by the adder, and the added value is multiplied by 1 / N to obtain an average temperature of all N phases. . Up to this point, the processing is common to the first phase, the second phase, and the Nth phase. The detection result obtained by converting the detection voltage of the temperature sensor Ts1 by the A / D converter 19 becomes the feedback temperature of the first phase.

  The CPU 11 uses this average temperature as a target value, and performs PI control that follows the target value based on the deviation of the feedback temperature with respect to the target value. The PI control may be other feedback control such as PID control. The operation amount generated by the PI control here is a first-phase correction amount with respect to the above-described representative duty ratio. The functional configuration of the control unit 10a that performs feedback control of the temperature related to the transistors Q2, Q3,... QN of the second phase, third phase,... Nth phase is the same as that shown in FIG. .

  If the correction amount from the first phase to the Nth phase is zero in the functional block shown in FIG. 2 and all the voltage conversion circuits 1a are driven by PWM signals having a typical duty ratio, each transistor Qi The transistors Q1, Q2,..., QN are not necessarily equal in temperature due to differences in ON resistance, thermal resistance related to heat dissipation, and the like. In the first embodiment, the transistors Q1, Q2,... QN detected by the temperature sensors Ts1, Ts2,. .. A correction amount for correcting the duty ratio for turning on / off QN is calculated.

  For example, the detection results obtained by A / D converting the detection voltages of the temperature sensors Ts1, Ts2,... TsN are T1, T2,... TN, and an average value represented by an average value of T1, T2,. Let Tav be the temperature. TaV is not limited to the average value of T1, T2,... TN, and may be a statistical value such as a median value or a representative value representing T1, T2,.

  When the temperature detection result T1 relating to the first-phase transistor Q1 is larger (or smaller) than Tav, the sign of the deviation shown in FIG. 3 is negative (or positive), and the sign is negative to bring the deviation closer to 0 by PI control. A (or positive) correction amount is calculated. As a result, the duty ratio of the first phase is controlled to be smaller (or larger) than the representative duty ratio, and the temperature related to the transistor Q1 is lowered (or increased). In this case, the absolute value of the correction amount increases as the absolute value of the deviation increases, and the temperature of the transistor Q1 is controlled to be lower (or higher). The same applies to each phase other than the first phase.

Below, operation | movement of the control part 10a mentioned above is demonstrated using the flowchart which shows it. The following processing is executed by the CPU 11 in accordance with a control program stored in advance in the ROM 12.
FIG. 4 is a flowchart illustrating a processing procedure of the CPU 11 that calculates a correction amount of the duty ratio of each phase and calculates a phase for turning on / off the PWM signal in the power supply device according to the first embodiment. The process whose procedure is shown in FIG. 4 is executed at every control cycle of PWM control. The loop counter k used in FIG. 4 is stored in the RAM 13. It is assumed that the target voltage is acquired or set in advance.

  When the process shown in FIG. 4 is started, the CPU 11 converts the output voltage divided by the voltage dividing circuit of the resistors R1 and R2 by the A / D converter 19 and takes in the detection result of the output voltage (S11). ), And the deviation of the detection result with respect to the target voltage is calculated (S12). Next, the CPU 11 calculates a representative duty ratio for each phase by executing PI control that follows the target voltage according to the calculated deviation (S13).

  Thereafter, the CPU 11 captures the detection results of the temperature sensors Ts1, Ts2,... TsN using the A / D converter 19 (S14), and multiplies the total value of the captured detection results by 1 / N, thereby The average temperature of the N phase is calculated (S15). The calculated average temperature is the target temperature. Next, the CPU 11 sets the loop counter k to 1 before entering the first loop process (S16).

  At the beginning of the first loop process, the CPU 11 calculates the deviation of the k-th phase temperature (that is, the detection result of the k-th phase temperature sensor Tsk) from the calculated average temperature (S17). Next, the CPU 11 calculates a correction amount of the duty ratio of the k-th phase by executing PI control that follows the target temperature according to the calculated deviation (S18), and sets the calculated correction amount to a representative duty ratio. The k-phase duty ratio is corrected by addition (S19).

  Thereafter, the CPU 11 increments the loop counter k by 1 (S23), and determines whether k is N + 1 (S24). When k is not N + 1 (S24: NO), the CPU 11 shifts the process to step S17 and continues the first loop process.

  When k is N + 1 (S24: YES), the CPU 11 exits the first loop process and calculates an off phase for turning off the first phase PWM signal (S31). The on phase for turning on the PWM signal of the first phase is assumed to be phase 0. Next, the CPU 11 sets the loop counter k to 1 before entering the second loop process (S32).

  At the head of the second loop process, the CPU 11 shifts the ON phase for turning on the k-th phase PWM signal by 2πk / N, and calculates the ON phase of the k + 1-th phase PWM signal (S33). Then, an off phase for turning off the PWM signal of the (k + 1) th phase is calculated according to the previously calculated duty ratio of the (k + 1) th phase (S34).

  Thereafter, the CPU 11 increments the loop counter k by 1 (S35), and determines whether k is N (S36). When k is not N (S36: NO), the CPU 11 shifts the process to step S32 and continues the second loop process. On the other hand, when k is N (S36: YES), the CPU 11 ends the process shown in FIG.

As described above, according to the first embodiment, the control unit 10a turns on / off the N voltage conversion circuits 1a, 1a,... With the respective phases different by 2π / N. The currents flowing through the inductors L1, L2,... Are switched by the transistors Q1, Q2,..., So that the voltages input to the voltage conversion circuits 1a, 1a,. . Further, the control unit 10a turns on the respective transistors Q1, Q2,... Based on the temperatures detected by the respective temperature sensors Ts1, Ts2,. A correction amount for correcting the duty ratio to be turned off is calculated for each. As a result, the duty ratio for turning on / off a transistor having a relatively high temperature (or low) is corrected to be small (or large).
Therefore, it is possible to reduce the temperature difference of each phase in the voltage conversion circuits 1a, 1a,.

Further, according to the first embodiment, the average value Tav of the temperature detection results relating to the transistors Q1, Q2,... Is calculated, and the temperature detection relating to each of the transistors Q1, Q2,. A deviation of the result is further calculated, and a correction amount for correcting the duty ratio for turning on / off each of the transistors Q1, Q2,... Is calculated based on the calculated deviation.
Therefore, the duty ratio for turning on / off the transistor whose temperature detection result deviation is negative (or positive) with respect to the average value (corresponding to the representative value) Tav of the temperature detection result depends on the absolute value of the deviation. It becomes possible to correct so that it may become small (or large).

Further, according to the first embodiment, the temperature related to the transistors Q1, Q2,... Is set as the control amount, and the average value (representative value) Tav of the temperature detection results related to the transistors Q1, Q2,. By performing PI control or PID control in parallel with the number N of voltage conversion circuits 1a, that is, the number of transistors Q1, Q2,..., The duty ratio is corrected as an operation amount for each of the transistors Q1, Q2,. Calculate the amount.
Therefore, it is possible to reduce the offset generated in the temperature related to the transistors Q1, Q2,.

(Embodiment 2)
In contrast to the first embodiment in which the voltage conversion circuit 1a that boosts the input voltage is configured in multiple phases, the second embodiment has a multi-phase voltage conversion circuit that steps down the input voltage. It is a form.

  FIG. 5 is a block diagram illustrating a configuration example of the power supply device according to the second embodiment. In the figure, 1b is a voltage conversion circuit that steps down the voltage from the external power supply 2 and supplies it to the external load 3. The power supply device includes voltage conversion circuits 1b and 1b and the voltage conversion circuits 1b and 1b. And a control unit 10b that controls the conversion. The number of voltage conversion circuits 1b is not limited to two.

  The voltage conversion circuit 1b includes an inductor L1 (or L2), a transistor Q1 (or Q2) that switches a current flowing from the power source 2 to the inductor L1 (or L2), and a temperature that detects a temperature related to the transistor Q1 (or Q2). Sensor Ts1 (or Ts2).

  A connection point between one end of each of the inductors L1 and L2 and the sources of the transistors Q1 and Q2 is connected to the drains of the transistors Qs1 and Qs2 for synchronous rectification. The drains of the transistors Q1 and Q2 are connected to the power source 2. The sources of the transistors Qs1 and Qs2 are connected to the ground potential. The voltages converted by the voltage conversion circuits 1b and 1b are output in parallel from the other ends of the inductors L1 and L2, are smoothed by the capacitor C1, and are divided by the voltage dividing circuit of the resistors R1 and R2 to be controlled. 10b.

  The control unit 10b generates a drive signal for turning on / off the CPU 11, the ROM 12, the RAM 13, the timer 14, the transistors Q1 and Q2, and applies them to the gates, and the transistors Qs1 and Qs2. A / D conversion is performed on drive circuits 17 and 17 that generate drive signals for turning on / off and apply to the gates, detection voltages of the temperature sensors Ts1 and Ts2, and a divided voltage divided by the resistors R1 and R2. The A / D converter 19 is provided. The CPU 11, ROM 12, RAM 13, timer 14, drive circuits 16, 16, 17, 17 and A / D converter 19 are mutually connected by a bus.

  As compared with the drive circuit 15 in the first embodiment, the drive circuit 16 is added with a bootstrap circuit that superimposes a DC voltage on the drive voltage applied to the gate. The drive voltages applied to the transistors Qs1 and Qs2 by the drive circuits 17 and 17 are different in phase by π from the drive voltages applied to the transistors Q1 and Q2 by the drive circuits 16 and 16, respectively.

  In addition, the same code | symbol is attached | subjected to the location corresponding to Embodiment 1, and the description is abbreviate | omitted. In addition, a block diagram showing a functional configuration of the control unit 10b that performs feedback control of the output voltage and a block diagram showing a functional configuration of the control unit 10b that performs feedback control of the temperature related to the first-phase transistor Q1 are also implemented. Since it is the same as that shown in FIGS. 2 and 3 of the first embodiment, the illustration is omitted. In the following description, it is assumed that the power supply device includes N voltage conversion circuits 1b (N is a natural number of 2 or more).

  In the second embodiment, the CPU 11 uses a target voltage acquired from an external interface (not shown) or a target voltage set by its own processing as a target value, and follows the target value based on the deviation of the feedback voltage of the output voltage with respect to the target value. PI control to be performed. The operation amount generated by the PI control is a typical duty ratio for the drive circuits 16, 16,.

  The generated representative duty ratio is added to each of the correction amounts from the first phase to the Nth phase by N adders. Each of the N duty ratios generated by the addition is supplied to different drive circuits 16. The PWM signals generated by the drive circuits 16, 16,... 16 are different in phase by 2π / N.

  On the other hand, different temperature sensors Tsj (j is any of 1 to N) included in each of the N voltage conversion circuits 1b, 1b,... 1b detect the temperature related to the transistor Qj. The detection results of the temperature sensors Ts1, Ts2,... TsN are added by an adder, and the added value is multiplied by 1 / N to obtain an average temperature Tav of all N phases. The CPU 11 uses the average temperature Tav as a target value, and separately performs PI control that follows the target value based on the deviation of the feedback temperature of each phase with respect to the target value. The manipulated variable generated by the PI control is a correction amount for the first phase, the second phase,..., The Nth phase with respect to the representative duty ratio of each phase.

  Here, when the temperature detection result Tj related to the transistor Qj of the j-th phase is larger (or smaller) than Tav, the sign of the deviation in the temperature PI control becomes negative (or positive), and the deviation is brought close to 0 by the PI control. Accordingly, a correction amount having a negative (or positive) sign is calculated. As a result, the duty ratio of the j-th phase is controlled to be smaller (or larger) than the typical duty ratio, and the temperature related to the transistor Qj is lowered (or increased). In this case, the absolute value of the correction amount increases as the absolute value of the deviation increases, and the temperature of the transistor Qj is controlled to be lower (or higher).

  Since the flowchart showing the operation of the control unit 10b described above is the same as that shown in FIG. 4 of the first embodiment, illustration and description thereof are omitted.

As described above, according to the second embodiment, the control unit 10b turns on / off the N voltage conversion circuits 1b, 1b,..., And the respective transistors Q1, Q2,. The currents flowing through the inductors L1, L2,... Are switched by the transistors Q1, Q2,..., So that the voltages input to the voltage conversion circuits 1b, 1b,. . The control unit 10b further turns on the respective transistors Q1, Q2,... Based on the temperatures detected by the respective temperature sensors Ts1, Ts2,. A correction amount for correcting the duty ratio to be turned off is calculated for each. As a result, the duty ratio for turning on / off a transistor having a relatively high temperature (or low) is corrected to be small (or large).
Therefore, it is possible to reduce the temperature difference of each phase in the voltage conversion circuits 1b, 1b,.

(Embodiment 3)
Each of the first and second embodiments is configured to output a voltage obtained by stepping up and stepping down the input DC voltage, whereas the third embodiment is a mode in which the input AC voltage is converted and a DC voltage is output. is there.

  FIG. 6 is a block diagram illustrating a configuration example of the power supply device according to the third embodiment. In the figure, 1c is a voltage conversion circuit that converts an AC voltage from an external AC power supply 4 and supplies a DC voltage to an external load 3. The power supply device includes voltage conversion circuits 1c and 1c, and the voltage conversion circuit 1c. , 1c, and a control unit 10c for controlling voltage conversion. The power supply device according to the third embodiment includes a so-called semi-bridgeless PFC circuit.

  The power supply device further includes diodes D3 and D4 having anodes connected to one end and the other end of the AC power supply 4, and resistors R3 and R4 connected in series between the cathodes of the diodes D3 and D4 and the ground potential. A circuit and diodes D5 and D6 each having a cathode connected to one end and the other end of the AC power supply 4 are provided. The anodes of the diodes D5 and D6 are connected to the ground potential. The series circuit of the diodes D3 and D4 and the resistors R3 and R4 is for detecting the voltage of the AC power supply 4. The diodes D5 and D6 are for linking the AC voltage potential of the AC power supply 4 and the ground potential.

  The voltage conversion circuit 1c includes an inductor L1 (or L2), a transistor Q1 (or Q2) that switches current flowing from one end (or the other end) of the AC power supply 4 to the inductor L1 (or L2), and a transistor Q1 (or Q2). And a temperature sensor Ts1 (or Ts2) for detecting the temperature according to ().

  The connection point between the inductors L1 and L2 and the drains of the transistors Q1 and Q2 is connected to the anodes of the diodes D1 and D2. The sources of the transistors Q1 and Q2 are connected to the ground potential via resistors R5 and R6 that detect the drain current. The voltages converted by the voltage conversion circuits 1c and 1c are output in parallel from the cathodes of the diodes D1 and D2 and smoothed by the capacitor C1, and are divided by the voltage dividing circuit of the resistors R1 and R2 to be controlled by the control unit 10c. Given to.

  The control unit 10c includes a CPU 11, a ROM 12, a RAM 13, a timer 14, drive circuits 18 and 18 that generate drive signals for turning on and off the transistors Q1 and Q2, and apply them to the gates, and temperature sensors Ts1 and Ts2. A / D for A / D conversion of the detection voltage of the resistors R1 and R2, the divided voltage of the resistors R3 and R4, and the detection voltages of the resistors R5 and R6 And a converter 19. The CPU 11, ROM 12, RAM 13, timer 14, drive circuits 18 and 18, and A / D converter 19 are connected to each other via a bus.

  In the third embodiment, the CPU 11 performs PFC control by switching the current flowing through the inductor L1 (or L2) a plurality of times by the transistor Q1 (or Q2) during each half cycle of the AC voltage from the AC power supply 4. . For example, in the continuous current mode, ON / OFF of the transistor Q1 (or Q2) is controlled so that the moving average value of the alternating current from the alternating current power supply 4 is proportional to the alternating voltage. In this case, the duty ratio for turning on / off the transistor Q1 (or Q2) is maximum at the phase 0 (or π) in each cycle of the AC voltage, and is minimum at the phase π / 2 (or 3π / 2). On the other hand, in the current critical mode, the duty ratio for turning on / off the transistor Q1 (or Q2) is constant, and the alternating current is adjusted by changing the switching cycle according to the alternating voltage.

  Hereinafter, when the voltage at one end with respect to the other end of the AC power supply 4 is positive and negative, the voltage of the AC power supply 4 is said to be positive and negative. When the voltage of the AC power supply 4 is positive, when the transistor Q1 is turned on, a current flows from one end of the AC power supply 4 via the inductor L1, the transistor Q1, the parasitic diode of the transistor Q2, and the inductor L2. In this case, the current increases linearly at an increasing rate substantially proportional to the positive AC voltage due to the inductive reactance of the inductors L1 and L2. On the other hand, when the transistor Q1 is turned off, current flows from one end of the AC power supply 4 via the inductor L1, the diode D1, the capacitor C1, the load 3, and the inductor L2, and the current decreases with time.

  When the voltage of the AC power supply 4 is negative, when the transistor Q2 is turned on, a current flows from the other end of the AC power supply 4 via the inductor L2, the transistor Q2, the parasitic diode of the transistor Q1, and the inductor L1. In this case, the current increases linearly at an increasing rate substantially proportional to the negative AC voltage due to the inductive reactance of the inductors L2 and L1. On the other hand, when the transistor Q2 is turned off, the current flows back from the other end of the AC power supply 4 via the inductor L2, the diode D2, the capacitor C1, the load 3, and the inductor L1, and the current decreases with time.

  The CPU 11 also performs temperature feedback control for the transistors Q1 and Q2. The CPU 11 calculates an average temperature Tav of the temperatures related to the transistors Q1 and Q2 based on the detection results of the temperature sensors Ts1 and Ts2. The CPU 11 sets the average temperature Tav as a target value, and separately performs PI control that follows the target value based on the temperature deviations of the transistors Q1 and Q2 with respect to the target value. The operation amount generated by the PI control is a correction amount for the duty ratio for turning on / off the transistors Q1 and Q2.

  Here, when the temperature detection result relating to the transistor Q1 is larger (or smaller) than Tav, the sign of the deviation in the temperature PI control is negative (or positive), and the sign is negative (to make the deviation close to 0 by PI control). Or, a positive correction amount is calculated. As a result, the duty ratio for turning on / off the transistor Q1 is reduced (or increased), and the temperature of the transistor Q1 is controlled to be lower (or higher). In this case, the absolute value of the correction amount increases as the absolute value of the deviation increases, and the temperature of the transistor Q1 is controlled to be lower (or higher). The same applies to the temperature control of the transistor Q2.

As described above, according to the third embodiment, the control unit 10c turns on / off the transistors Q1 and Q2 of the voltage conversion circuits 1c and 1c in different phases, and the current flowing through the inductors L1 and L2 is supplied to the transistor Q1. By switching at Q2 and Q2, the voltage input to the voltage conversion circuits 1c and 1c is converted and output in parallel. The controller 10c further corrects the duty ratio for turning on / off each of the transistors Q1 and Q2 based on the temperature detected by the temperature sensors Ts1 and Ts2 in time series with respect to the temperatures of the transistors Q1 and Q2. The correction amount is calculated separately. As a result, the duty ratio for turning on / off a transistor having a relatively high temperature (or low) is corrected to be small (or large).
Accordingly, it is possible to reduce the temperature difference between the phases in the voltage conversion circuits 1c and 1c having a multiphase configuration.

(Embodiment 4)
In contrast to the first embodiment in which the current flowing through the inductors L1, L2,... Is not detected, the fourth embodiment detects the current flowing through the inductors L1, L2,. In this embodiment, the duty ratio for turning on / off the transistor corresponding to the inductor is reduced.

  FIG. 7 is a block diagram illustrating a configuration example of the power supply device according to the fourth embodiment. In the figure, reference numeral 1d denotes a voltage conversion circuit, and the power supply apparatus includes voltage conversion circuits 1d and 1d and a control unit 10d that controls voltage conversion by the voltage conversion circuits 1d and 1d. The number of voltage conversion circuits 1d is not limited to two. The difference between the voltage conversion circuits 1d and 1d and the voltage conversion circuits 1a and 1a provided in the power supply apparatus according to the first embodiment is that the voltage conversion circuits 1d and 1d detect currents flowing through the inductors L1 and L2, respectively. It is in the point which has. The detection voltages by the current sensors Cs1 and Cs2 are converted by the A / D converter 19 and referred to as a current detection result.

  In addition, the same code | symbol is attached | subjected to the location corresponding to Embodiment 1, and the description is abbreviate | omitted. In addition, a block diagram illustrating a functional configuration of the control unit 10d that performs feedback control of the output voltage and a block diagram illustrating a functional configuration of the control unit 10d that performs temperature feedback control related to the first-phase transistor Q1 are also implemented. Since it is the same as that shown in FIGS. 2 and 3 of the first embodiment, the illustration and description of the contents are omitted.

Below, operation | movement of the control part 10d mentioned above is demonstrated using the flowchart which shows it. The power supply device includes N voltage conversion circuits 1d (N is a natural number of 2 or more).
FIG. 8 is a flowchart illustrating the processing procedure of the CPU 11 that calculates the correction amount of the duty ratio of each phase and calculates the phase at which the PWM signal is turned on / off by the power supply device according to the fourth embodiment. Of the processing shown in FIG. 8, the processing from step S41 to S49 and the processing from step S61 to S66 are the same as the processing from step S11 to S19 and the processing from step S31 to S36 shown in FIG. Therefore, most of the description is omitted.

  When the processing shown in FIG. 8 is started and the processing from step S41 to S49 is completed, the CPU 11 captures the detection result of the k-phase current sensor Csk in the first loop processing (S50), and the detection result is It is determined whether it is larger than a predetermined threshold (S51). The detection result of the current sensor Csk is preferably averaged or peak-held over the control period of the PWM signal. The average value or peak value of the detection results of the current sensor Csk may be acquired by a process different from the process shown in FIG.

  When the detection result of the current sensor Csk is larger than the predetermined threshold (S51: YES), the CPU 11 reduces the duty ratio of the k-th phase (S52). This reduction may be reduced at a constant reduction rate or may be reduced by a predetermined duty ratio. When the process of step S52 is completed, or when the detection result of the current sensor Csk is not greater than the predetermined threshold value in step S51 (S51: NO), the CPU 11 increments the loop counter k by 1 (S53). It is determined whether or not N + 1 (S54). Since the following processing is the same as that shown in FIG. 4 of the first embodiment, description thereof is omitted.

As described above, according to the fourth embodiment, when the current flowing through each of the N inductors L1, L2,... Is larger than the threshold, the transistor corresponding to the inductor in which the current larger than the threshold is detected is turned on / off. Reduce the duty ratio.
Therefore, it is possible to prevent the transistors Q1, Q2,... From being deteriorated or damaged at a high temperature.

Further, according to the first embodiment (or 4), the CPU 11 that executes the computer program in the control unit 10a sends the detection results of the temperature sensors Ts1, Ts2,. Step S14 (or S44) acquired in time series and step S18 for calculating a correction amount for correcting the duty ratio for turning on / off the corresponding transistors Q1, Q2,. (Or S48) and step S19 (or S49) for correcting the corresponding duty ratio based on the calculated correction amounts. As a result, the duty ratio for turning on / off a transistor having a relatively high temperature (or low) is corrected to be small (or large).
Therefore, it is possible to reduce the temperature difference of each phase in the voltage conversion circuits 1a, 1a,.

1a, 1b, 1c, 1d Voltage conversion circuit 10a, 10b, 10c Control unit 11 CPU
12 ROM
13 RAM
14 Timer 15, 16, 17, 18 Drive circuit 19 A / D converter
L1, L2 Inductors Q1, Q2, Qs1, Qs2 Transistors D1, D2, D3, D4, D5, D6 Diodes R1, R2, R3, R4, R5, R6 Resistors C1, C2 Capacitors Ts1, Ts2 Temperature sensor 2 Power supply 3 Load 4 AC power supply

Claims (5)

A plurality of voltage conversion circuits each having an inductor and a switching element that switches a current flowing through the inductor; and a control unit that turns each switching element on / off in a different phase, and connecting outputs of the voltage conversion circuits in parallel. A power supply,
Each voltage conversion circuit has a temperature sensor that detects the temperature of each switching element or the ambient temperature,
The said control part is a power supply device which calculates the correction amount which correct | amends the duty ratio which turns on / off the switching element corresponding to each temperature sensor based on the time-sequential detection result of each temperature sensor.   The power supply device according to claim 1, wherein the control unit calculates the correction amount based on a deviation of a detection result of each temperature sensor with respect to a representative value of a detection result of each temperature sensor.   The power supply device according to claim 2, wherein the control unit calculates the correction amount by PI control or PID control in which a temperature or an ambient temperature of each switching element is a control amount and the representative value is a target value. Each voltage conversion circuit further includes a current sensor that detects a current flowing through each inductor,
The control unit determines whether or not a detection result of each current sensor is greater than a predetermined threshold, and reduces a duty ratio for turning on / off a switching element corresponding to the current sensor determined to be large. The power supply device according to any one of the above. A plurality of voltage conversion circuits each including an inductor, a switching element that switches a current flowing through the inductor, and a temperature sensor that detects a temperature of the switching element or an ambient temperature, and a control that turns each switching element on and off at different phases A computer program that can be executed by the control unit in the power supply device that includes the output unit and connected in parallel to the output of each voltage conversion circuit,
In the control unit,
Acquiring the detection results of each temperature sensor in time series;
Calculating a correction amount for correcting a duty ratio for turning on / off a switching element corresponding to each temperature sensor, based on each acquired detection result;
A computer program that executes the step of correcting the duty ratio based on the calculated correction amount.

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