JP6079398B2 - Power converter - Google Patents

Description

  The present invention relates to a power conversion device, and more particularly to a power conversion device including a pair of conversion circuits that have three or more input / output ports and are magnetically coupled to each other.

  Conventionally, a power converter provided with a pair of conversion circuits which are magnetically coupled to each other is known (see, for example, Patent Document 1). In this power conversion device, each of the pair of conversion circuits has a full bridge circuit including a coil constituting a center tap type transformer. The primary side conversion circuit has two input / output ports and a primary side coil. The secondary conversion circuit has two input / output ports and a secondary coil. A primary side secondary battery is connected to one of the two input / output ports of the primary side conversion circuit, and a load is connected to the other input / output port. Further, a secondary secondary battery is connected to one of the two input / output ports of the secondary side conversion circuit. In such a power conversion device, power conversion is performed between any two input / output ports among a total of four input / output ports of the primary side conversion circuit and the secondary side conversion circuit.

JP 2011-193713 A

  By the way, in the above-described power conversion device that is a multi-port power supply, power is supplied from the secondary side secondary battery on the secondary side conversion circuit side to the load on the primary side conversion circuit side or the primary side secondary battery. Sometimes. Further, power may be supplied from the primary side secondary battery on the primary side conversion circuit side to the load or secondary side secondary battery on the secondary side conversion circuit side. When power transmission is performed between the primary side conversion circuit and the secondary side conversion circuit, if the upstream side conversion circuit fails, the power transmission becomes impossible. In this case, if no control is performed, the voltage appearing at the output port of the downstream conversion circuit decreases, so that the operation of the load of the downstream conversion circuit cannot be continued, and the load stops operating. End up.

  The present invention has been made in view of the above points, and provides a power conversion device capable of continuing the operation of a load when power transmission between conversion circuits that are magnetically coupled to each other becomes difficult. For the purpose.

The above object is provided between the first full bridge circuit including the first coil constituting the center tap type transformer and the positive and negative buses of the first full bridge circuit, to which a load is connected. A first conversion circuit comprising: a first input / output port; and a second input / output port provided between a negative bus of the first full bridge circuit and a center tap of the transformer and connected to the first battery. When the transformer by linked the first conversion circuit and the magnetic, and the second full bridge circuit including a second coil constituting the transformer, between the positive bus and the negative bus of said second full bridge circuit A second conversion circuit provided with a third input / output port to which a second battery different from the first battery is connected , and the voltage of the third input / output port is stepped down or boosted to a target voltage Second battery As a first control for supplying power to al the load and the first battery, the phase difference corresponding to the difference between the actual voltage and the target voltage of said first input-output port, and the actual of said second output port And a control unit having first control drive control means for driving the first full bridge circuit and the second full bridge circuit at a duty ratio corresponding to the difference between the voltage and the target voltage. Voltage determining means for determining whether or not the voltage of the first input / output port falls below a predetermined value equal to or lower than a target voltage, and the controller is configured to perform the first control by the voltage determining means. When it is determined that the voltage of the first input / output port is lower than the predetermined value , the first input / output port is used as a second control for supplying power from the first battery to the load instead of the first control. Actual voltage and target power Is achieved by the power converter, characterized in that it comprises a second control drive control means for driving the first full bridge circuit with a duty ratio corresponding to the difference between.

  According to the present invention, it is possible to continue the operation of the load when power transmission between the conversion circuits that are magnetically coupled to each other becomes difficult.

It is a block diagram of the power converter device which is one Example of this invention. It is a figure showing the timing by which the transistor in a primary side converter circuit and a secondary side converter circuit is each switching-driven in the power converter device of a present Example. It is a circuit block diagram for performing the switching drive of the transistor in the power converter device of a present Example. It is a flowchart of an example of the control routine performed in the power converter device of a present Example. It is an operation | movement time chart of an example in the power converter device of a present Example.

  Hereinafter, specific embodiments of a power conversion device according to the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration diagram of a power conversion apparatus 10 according to an embodiment of the present invention. The power conversion device 10 of this embodiment is mounted on, for example, a vehicle, and is interposed between a high-voltage main battery or a low-voltage auxiliary battery and a load, and any two of the plurality of input / output ports. This is a multi-port power supply device that performs power conversion between two input / output ports.

  The power conversion device 10 includes a power conversion circuit 12 and a control unit 14. The power conversion circuit 12 includes a primary side conversion circuit 16 and a secondary side conversion circuit 18. The primary side conversion circuit 16 and the secondary side conversion circuit 18 are magnetically coupled to each other and constitute a pair of conversion circuits. Magnetic coupling between the primary side conversion circuit 16 and the secondary side conversion circuit 18 is performed using a center tap type transformer 20.

  The primary side conversion circuit 16 includes a primary side full bridge circuit 22. The primary side full bridge circuit 22 includes a primary side coil 24 and a primary side magnetic coupling reactor 26 that constitute the transformer 20. The primary coil 24 is divided into a primary coil 24 a and a primary coil 24 b through a center tap 28. The primary side magnetic coupling reactor 26 is provided with two, the primary side magnetic coupling reactor 26a and the primary side magnetic coupling reactor 26b which are mutually magnetically coupled. One end of the primary side magnetic coupling reactor 26a is connected to the other end of the primary side coil 24a opposite to the one end on the center tap 28 side. One end of the primary side magnetic coupling reactor 26b is connected to the other end of the primary side coil 24b opposite to the one end on the center tap 28 side.

  The primary-side full bridge circuit 22 has four primary-side arm elements 30, 32, 34, and 36 that are connected in a full bridge. Each of the primary side arm elements 30 to 36 is configured by connecting switching elements 30a to 36a and diodes 30b to 36b in parallel. Each of the switching elements 30a to 36a is an element driven according to a drive signal from the control unit 14, and is, for example, a MOS transistor.

  The primary arm element 30 and the primary arm element 32 are connected in series between the positive bus 40 and the negative bus 42 of the primary full bridge circuit 22. The primary arm element 34 and the primary arm element 36 are connected in series between the positive bus 40 and the negative bus 42 of the primary full bridge circuit 22.

  Hereinafter, the primary side arm element 30 will be referred to as the primary side upper left arm element 30, the primary side arm element 32 as the primary side lower left arm element 32, and the primary side arm element 34 as the primary side upper right arm element 34. The primary side arm element 36 is referred to as a primary side lower right arm element 36, respectively. The primary left upper arm element 30 and the primary left lower arm element 32 are combined to form a primary left arm circuit, and the primary side upper right arm element 34 and the primary side lower right arm element 36 are combined to 1 These are called the secondary right arm circuits.

  The other end of the primary side magnetic coupling reactor 26a is connected to the midpoint of the primary side upper left arm element 30 and the primary side lower left arm element 32 of the primary side left arm circuit. The other end of the primary side magnetic coupling reactor 26b is connected to the midpoint between the primary side upper right arm element 34 and the primary side lower right arm element 36 of the primary side right arm circuit.

  The primary side conversion circuit 16 also has two input / output ports A and B. The input / output port A is a port provided between the positive electrode bus 40 and the negative electrode bus 42 of the primary side full bridge circuit 22, and is a terminal to which the positive electrode bus 40 is connected and the negative electrode bus 42 is connected. 46. The input / output port B is a port provided between the negative bus 42 of the primary side full bridge circuit 22 and the center tap 28 on the primary side of the transformer 20, and is a terminal to which the negative bus 42 is connected. 46 and a terminal 48 to which the center tap 28 is connected.

  A load 50 is connected to both ends of the input / output port A (that is, between the terminal 44 and the terminal 46). The load 50 is, for example, a load device that operates at a voltage of about 42 v to 46 v, such as an electric power steering device (EPS). A voltage at which the load 50 can operate is supplied to the input / output port A.

  Loads 52 and 53 are connected to both ends of the input / output port B (that is, between the terminal 46 and the terminal 48), and an auxiliary battery 54 is connected. The loads 52 and 53 are, for example, load devices that operate at a voltage of about 12 V, and are an electronically controlled brake system (ECB), an electronically controlled unit (ECU), and the like. The auxiliary battery 54 is connected to the loads 52 and 53 in parallel. The auxiliary battery 54 is a voltage lower than the operable voltage of the load 50 connected to the input / output port A, and is a secondary battery such as a lead storage battery that outputs a voltage of about 12 V, for example, capable of operating the loads 52 and 53. It is a battery. A voltage at which the loads 52 and 53 can operate is supplied to the input / output port B.

  The secondary side conversion circuit 18 has a secondary side full bridge circuit 60. The secondary-side full bridge circuit 60 has a secondary-side coil 62 and a secondary-side magnetic coupling reactor 64 that constitute the transformer 20 described above. The secondary coil 62 is divided into a secondary coil 62 a and a secondary coil 62 b through a center tap 66. The secondary side magnetic coupling reactor 64 is provided with the secondary side magnetic coupling reactor 64a and the secondary side magnetic coupling reactor 64b which are mutually magnetically coupled. One end of the secondary side magnetic coupling reactor 64a is connected to the other end of the secondary side coil 62a opposite to the one end on the center tap 66 side. Further, one end of the secondary side magnetic coupling reactor 64b is connected to the other end of the secondary side coil 62b opposite to the one end on the center tap 66 side.

  The secondary-side full bridge circuit 60 includes four secondary-side arm elements 70, 72, 74, and 76 that are connected by a full bridge. Each of the secondary arm elements 70 to 76 is configured by connecting switching elements 70 a to 76 a and diodes 70 b to 76 b in parallel. Each of the switching elements 70a to 76a is an element driven according to a drive signal from the control unit 14, and is, for example, a MOS transistor.

  The secondary side arm element 70 and the secondary side arm element 72 are connected in series between the positive electrode bus 80 and the negative electrode bus 82 of the secondary side full bridge circuit 60. The secondary arm element 74 and the secondary arm element 76 are connected in series between the positive bus 80 and the negative bus 82 of the secondary full bridge circuit 60.

  Hereinafter, the secondary side arm element 70 is appropriately changed to the secondary side upper right arm element 70, the secondary side arm element 72 is changed to the secondary side lower right arm element 72, and the secondary side arm element 74 is changed to the secondary side upper left arm element 74. The secondary arm element 76 is referred to as a secondary lower left arm element 76, respectively. The secondary right upper arm element 70 and the secondary lower right arm element 72 are combined into a secondary right arm circuit, and the secondary left upper arm element 74 and the secondary left lower arm element 76 are combined into 2 These are called secondary left arm circuits.

  The other end of the secondary side magnetic coupling reactor 64a is connected to the midpoint between the secondary side upper right arm element 70 and the secondary side lower right arm element 72 of the secondary side right arm circuit. The other end of the secondary side magnetic coupling reactor 64b is connected to the midpoint between the secondary left upper arm element 74 and the secondary left lower arm element 76 of the secondary left arm circuit.

  The secondary side conversion circuit 18 also has two input / output ports C and D. The input / output port C is a port provided between the positive electrode bus 80 and the negative electrode bus 82 of the secondary side full bridge circuit 60 and is connected to the terminal 84 to which the positive electrode bus 80 is connected and the negative electrode bus 82. 86. The input / output port D is a port provided between the negative bus 82 of the secondary side full bridge circuit 60 and the center tap 66 on the secondary side of the transformer 20, and is a terminal to which the negative bus 82 is connected. 86 and a terminal 88 to which the center tap 66 is connected.

  A main battery 90 is connected to both ends of the input / output port C (that is, between the terminal 84 and the terminal 86). The main battery 90 is a secondary battery such as lithium ion that outputs a voltage higher than the output voltage of the auxiliary battery 54 described above, for example, a voltage of about 200 v to 300 v that can drive the vehicle. Note that the main battery 90 may be connected to a load such as a drivable and regenerative motor generator. The output voltage of the main battery 90 is supplied to the input / output port C. A load that operates at a predetermined voltage may be connected to both ends of the input / output port D (that is, between the terminal 86 and the terminal 88).

  The control unit 14 has a function of switching and driving the switching elements 30 a to 36 a in the primary side conversion circuit 16 and the switching elements 70 a to 76 a in the secondary side conversion circuit 18. The control unit 14 is an arbitrary two of the four input / output ports including the two input / output ports A and B included in the primary side conversion circuit 16 and the two input / output ports C and D included in the secondary side conversion circuit 18. Power conversion is performed between two input / output ports.

  Specifically, the control unit 14 can perform step-down control in which the voltage of the input / output port C is stepped down and output to the input / output ports A and B, and the loads 50, 52, 53 and It is possible to supply power to the auxiliary battery 54. In addition, the control unit 14 can perform boost control that boosts the voltage of the input / output port B and outputs the boosted voltage to the input / output port A, and can supply power from the auxiliary battery 54 to the load 50. is there.

  A voltage generated at the input / output port A and a voltage generated at the input / output port B are input to the control unit 14. The control unit 14 controls the switching drive of each of the switching elements 30a to 36a and 70a to 76a based on the voltage generated at the input / output port A and the voltage generated at the input / output port B. Further, the control unit 14 has a function of determining whether an abnormal failure has occurred in the secondary side conversion circuit 18 based on the voltage of the input / output port A.

  Next, operation | movement is demonstrated to the power converter device 10 of a present Example using FIG.2 and FIG.3. FIG. 2 shows the timing at which the switching elements 30a to 36a in the primary side conversion circuit 16 and the switching elements 70a to 76a in the secondary side conversion circuit 18 are driven to be switched in the power conversion device 10 of the present embodiment. The figure is shown. FIG. 3 is a circuit configuration diagram for the control unit 14 to perform the switching drive in the power conversion device 10 of the present embodiment.

  In this embodiment, the switching drive U1 of the primary left arm circuit and the switching drive V1 of the primary right arm circuit are performed in opposite phases. The switching drive U1 of the primary left upper arm element 30 of the primary left arm circuit and the switching drive / U1 of the primary left lower arm element 32 are performed in opposite phases. The switching drive V1 of the primary right upper arm element 34 of the primary right arm circuit and the switching drive / V1 of the primary right lower arm element 36 are performed in opposite phases. The switching drive U1 of the primary left upper arm element 30 and the switching drive / V1 of the primary right lower arm element 36 are performed in phase with each other, and the switching drive U1 of the primary left lower arm element 32 and the primary side The switching drive V1 of the upper right arm element 34 is performed in phase with each other.

  The switching drive U2 of the secondary side right arm circuit and the switching drive V2 of the secondary side left arm circuit are performed in opposite phases. The switching drive U2 of the secondary right upper arm element 70 of the secondary right arm circuit and the switching drive / U2 of the secondary right lower arm element 72 are performed in opposite phases. The switching drive V2 of the secondary left upper arm element 74 of the secondary left arm circuit and the switching drive / V2 of the secondary left lower arm element 76 are performed in opposite phases. The switching drive U2 of the secondary upper right arm element 70 and the switching drive / V2 of the secondary left lower arm element 76 are performed in phase with each other, and the switching drive / U2 of the secondary right lower arm element 72 and the secondary side The switching drive V2 of the upper left arm element 74 is performed in phase with each other.

  When the control unit 14 causes each of the primary side conversion circuit 16 and the secondary side conversion circuit 18 to function as a step-up / down circuit, the ON time δ of each switching element 30a to 36a, 70a to 76a, that is, the duty ratio δ / T (however, , T has a function of setting a switching period). In addition, when the control unit 14 causes the power conversion device 10 to function as a DC-DC converter, the switching position between the switching elements 30a to 36a of the primary side conversion circuit 16 and the switching elements 70a to 76a of the secondary side conversion circuit 18. It has a function capable of setting the phase difference φ. The control unit 14 drives each of the switching elements 30a to 36a and 70a to 76a based on the set duty ratio δ / T and the set switching phase difference φ.

  Switching drive U1 of the primary side upper left arm element 30, switching drive of the primary side lower right arm element 36 / V1, switching drive U2 of the secondary side upper right arm element 70, and switching drive of the secondary side lower left arm element 76 / V2 is performed with the same duty ratio δ / T. Further, the switching drive / U1 of the primary left lower arm element 32, the switching drive V of the primary upper right arm element 34, the switching drive / U2 of the secondary right lower arm element 72, and the secondary drive upper left arm element 74 The switching drive V2 is performed at the same duty ratio (T−δ) / T.

  When the control unit 14 performs step-down control in which the voltage input from the main battery 90 to the input / output port C is stepped down and output to the input / output ports A and B, the input voltage of the input / output port C is supplied to the power converter 10. The voltage is converted by the function as a DC-DC converter and transmitted to the input / output port A, and the voltage of the input / output port A is stepped down by the step-down function of the primary side conversion circuit 16 and transmitted to the input / output port B. .

  The step-up / step-down ratio of the primary side conversion circuit 16 is adjusted by changing the on-time δ, that is, the duty ratio δ / T of the switching drives U1 and V1 of the arm elements 30 to 36. The step-up / step-down ratio of the secondary conversion circuit 18 is adjusted by changing the on-time δ of the switching drives U2 and V2 of the arm elements 70 to 76, that is, the duty ratio δ / T. In addition, the amount of electric power transmitted between the primary side conversion circuit 16 and the secondary side conversion circuit 18 is the switching drive U, V of the primary side full bridge circuit 22 and the switching drive U of the secondary side full bridge circuit 60, The switching phase difference φ from V (specifically, the switching phase difference φ between the switching drive U1 of the primary left upper arm element 30 and the switching drive U2 of the secondary upper right arm element 70, and the primary upper right arm) It is adjusted by changing the switching phase difference φ) between the switching drive V1 of the element 34 and the switching drive V2 of the secondary left upper arm element 74.

  Further, when the switching phase difference φ is such that the switching drives U1, V1 of the primary side full bridge circuit 22 are performed later than the switching drives U2, V2 of the secondary side full bridge circuit 60, the secondary phase Power transmission from the side conversion circuit 18 to the primary side conversion circuit 16 is performed. On the other hand, when the switching phase difference φ is such that the switching drive U1, V1 of the primary side full bridge circuit 22 is performed earlier than the switching drive U2, V2 of the secondary side full bridge circuit 60, the primary side. Power transmission from the conversion circuit 16 to the secondary side conversion circuit 18 is performed.

  Therefore, when performing the step-down control from the input / output port C to the input / output ports A and B as described above, the control unit 14 inputs / outputs the input power of the input / output port C of the power conversion circuit 10 with a desired power transmission amount. An on-time δ that defines a step-down ratio for stepping down the input voltage of the input / output port A by the step-down function of the primary side conversion circuit 16 while setting the switching phase difference φ for transmission to the ports A and B, that is, the duty ratio δ / T is set.

  Specifically, the control unit 14 includes a phase difference setting unit 100 that sets a switching phase difference φ between the primary side conversion circuit 16 and the secondary side conversion circuit 18. The phase difference setting unit 100 includes a voltage difference adder 102, a PID adder 104, an integrator 106, a differentiator 108, an integral gain unit 110, a differential gain unit 112, a proportional gain unit 114, and a variable gain. Instrument 116.

  The voltage difference adder 102 receives the target voltage of the input / output port A and the current voltage actually generated at the input / output port A. The voltage difference adder 102 calculates a differential pressure between the target voltage of the input / output port A and the current voltage. Specifically, the current voltage is subtracted from the target voltage of the input / output port A to calculate the differential pressure. The inputs of the PID adder 104, the integrator 106, and the differentiator 108 are connected to the output of the voltage difference adder 102. The differential pressure calculated by the voltage difference adder 102 is input to the PID adder 104 and also to the integrator 106 and the differentiator 108, respectively.

  The integrator 106 time-integrates the differential pressure calculated by the voltage difference adder 102. The input of the integral gain unit 110 is connected to the output of the integrator 106. The integral value calculated by the integrator 106 is input to the integral gain unit 110. The integral gain unit 110 amplifies the integral value calculated by the integrator 106 with a predetermined integral gain I1. The differentiator 108 time-differentiates the differential pressure calculated by the voltage difference adder 102. The input of the differential gain unit 112 is connected to the output of the differentiator 108. The differential value calculated by the differentiator 108 is input to the differential gain unit 112. The differential gain unit 112 amplifies the differential value calculated by the differentiator 108 with a predetermined differential gain D1.

  The input of the PID adder 104 is connected to the output of the integral gain unit 110 and the output of the differential gain unit 112. The value calculated by the integral gain unit 110 and the value calculated by the differential gain unit 112 are input to the PID adder 104, respectively. The PID adder 104 calculates the target voltage and the current voltage of the input / output port A based on the differential pressure calculated by the voltage difference adder 102, the value calculated by the integral gain unit 110, and the value calculated by the differential gain unit 112. Is calculated as a command value for the switching phase difference φ. The switching phase difference φ increases as the differential pressure between the target voltage of the input / output port A calculated by the voltage difference adder 102 and the current voltage increases.

  The input of the proportional gain unit 114 is connected to the output of the PID adder 104. The PID value calculated by the PID adder 104 is input to the proportional gain unit 114. The proportional gain unit 114 amplifies and outputs the PID value calculated by the PID adder 104 with a predetermined proportional gain P1.

  The input of the variable gain device 116 is connected to the output of the proportional gain device 114. The value calculated by the proportional gain unit 114 is input to the variable gain unit 116. The variable gain unit 116 amplifies the value calculated by the proportional gain unit 114 by a predetermined gain constant β. The phase difference setting device 100 outputs the calculation result of the variable gain device 116 as an output value of the phase difference setting device 100, that is, a command value of the switching phase difference φ between the primary side conversion circuit 16 and the secondary side conversion circuit 18. The gain constant β of the variable gain device 116 is a variable that is normally set to “1”, and is set to “0” when an abnormal failure occurs in the secondary side conversion circuit 18 as will be described later. .

  When the gain constant β is set to “1”, the phase difference setting device 100 sets a value corresponding to the differential pressure between the target voltage of the input / output port A and the current voltage as usual. 16 is output as a command value of the switching phase difference φ between the primary side full bridge circuit 22 of the 16 and the secondary side full bridge circuit 60 of the secondary side conversion circuit 18. In this case, the switching drive of the switching elements 30a to 36a of the primary side conversion circuit 16 and the switching drive of the switching elements 70a to 76a of the secondary side conversion circuit 18 are performed with a switching phase difference φ. The power converter 10 functions as a DC-DC converter.

  On the other hand, when the gain constant β is set to “0”, the phase difference setting device 100 instructs the zero switching phase difference φ regardless of the differential pressure between the target voltage of the input / output port A and the current voltage. Output the value. In this case, the power converter 10 does not function as a DC-DC converter.

  In addition, the control unit 14 includes a duty ratio setting device 120 that sets the step-up / step-down ratio of the primary side conversion circuit 16. The duty ratio setting unit 120 includes a voltage difference adder 122, switching adders 124, 126, and 128, a PID adder 130, an integrator 132, a differentiator 134, an integral gain unit 136, and a differential gain unit. 138, a proportional gain device 140, and variable gain devices 142, 144, 146, 148.

  The voltage difference adder 122 receives the target voltage of the input / output port B and the current voltage actually generated at the input / output port B. The voltage difference adder 122 calculates a differential pressure between the target voltage of the input / output port B and the current voltage. Specifically, the current voltage is subtracted from the target voltage of the input / output port B, and the differential pressure is calculated.

  The input of the variable gain device 142 is connected to the output of the voltage difference adder 122. The differential pressure at the input / output port B calculated by the voltage difference adder 122 is input to the variable gain unit 142. The variable gain unit 142 amplifies the differential pressure of the input / output port B calculated by the voltage difference adder 122 by a predetermined gain constant β. Note that the gain constant β of the variable gain device 142 is the same value as the gain constant β of the variable gain device 116 and is normally set to “1”, while “0” when an abnormal failure occurs in the secondary side conversion circuit 18. "Is set.

  The output of the voltage difference adder 102 is also connected to the input of the variable gain device 144. The differential pressure at the input / output port A calculated by the voltage difference adder 102 is also input to the variable gain unit 144. The variable gain unit 144 amplifies the differential pressure of the input / output port A calculated by the voltage difference adder 102 by a predetermined gain constant α. The gain constant α of the variable gain device 144 is a parameter that is normally set to “0”, but is set to “1” when the secondary side conversion circuit 18 has an abnormal failure.

  The input of the switching adder 124 is connected to the output of the variable gain device 142 and the output of the variable gain device 144. The calculated values of the variable gain units 142 and 144 are input to the switching adder 124. The switching adder 124 outputs one of the output of the variable gain unit 142 and the output of the variable gain unit 144. Inputs of the PID adder 130, the integrator 132, and the differentiator 134 are connected to the output of the switching adder 124. The output of the switching adder 124 is input to the PID adder 130 and to the integrator 132 and the differentiator 134, respectively.

  The integrator 132 time-integrates the value output from the switching adder 124. The input of the integral gain unit 136 is connected to the output of the integrator 132. The integral value calculated by the integrator 132 is input to the integral gain unit 136. The integral gain unit 136 amplifies the integral value calculated by the integrator 132 with a predetermined integral gain I2. The differentiator 134 time-differentiates the value output from the switching adder 124. The input of the differential gain unit 138 is connected to the output of the differentiator 134. The differential value calculated by the differentiator 134 is input to the differential gain unit 138. The differential gain unit 138 amplifies the differential value calculated by the differentiator 134 with a predetermined differential gain D2.

  The input of the PID adder 130 is connected to the output of the integral gain unit 136 and the output of the differential gain unit 138. The value calculated by the integral gain unit 136 and the value calculated by the differential gain unit 138 are input to the PID adder 130, respectively. The PID adder 130 calculates the target voltage of the input / output port B and the current voltage based on the value output from the switching adder 124, the value calculated by the integral gain unit 136, and the value calculated by the differential gain unit 138. The PID value of the differential pressure (or the differential pressure between the target voltage of the input / output port A and the current voltage when an abnormal failure occurs in the secondary side conversion circuit 18) is used as the switching drive U, V ( Specifically, it is calculated as the duty ratio δ / T of the switching drive U1) of the primary left upper arm element 30. The duty ratio δ / T as the output of the PID adder 130 becomes larger as the differential pressure between the target voltage of the input / output port B calculated by the voltage difference adder 122 and the current voltage increases (that is, Close to 100%).

  The input of the proportional gain device 140 is connected to the output of the PID adder 130. The PID value calculated by the PID adder 130 is input to the proportional gain device 140. The proportional gain device 140 amplifies and outputs the PID value calculated by the PID adder 130 with a predetermined proportional gain P2.

  The output of the proportional gain device 140 is connected to the input of the variable gain device 146 and the input of the switching adder 126. The value calculated by the proportional gain device 140 is input to the variable gain device 146 and the switching adder 126. The variable gain unit 146 amplifies the value calculated by the proportional gain unit 140 by a predetermined gain constant β. Note that the gain constant β of the variable gain device 146 is the same value as the gain constant β of the variable gain devices 116 and 142, and is normally set to “1”, but at the time of an abnormal failure of the secondary side conversion circuit 18. Set to “0”. The switching adder 126 is also input with 100% duty information. The switching adder 126 subtracts the value calculated by the proportional gain device 140 from the duty 100%.

  The output of the switching adder 126 is connected to the input of the variable gain device 148. The value calculated by the switching adder 126 is input to the variable gain device 148. The variable gain unit 148 amplifies the value calculated by the switching adder 126 by a predetermined gain constant α. Note that the gain constant α of the variable gain device 148 is the same value as the gain constant α of the variable gain device 144 and is normally set to “0”, but when an abnormal failure occurs in the secondary side conversion circuit 18 as will be described later. Is set to “1”.

  The input of the switching adder 128 is connected to the output of the variable gain device 146 and the output of the variable gain device 148. The calculated values of the variable gain units 146 and 148 are input to the switching adder 128. The switching adder 128 outputs one of the output of the variable gain unit 146 and the output of the variable gain unit 148. The duty ratio setting unit 120 outputs the calculation result of the switching adder 128 to the output of the duty ratio setting unit 120, that is, the switching drive U of the primary side full bridge circuit 22 (specifically, the primary left upper arm element 30). It is output as a duty command value for the switching drive U1).

  When the gain constant β is set to “1” and the gain constant α is set to “0”, the duty ratio setting device 120 performs a differential pressure between the target voltage of the input / output port B and the current voltage as usual. Is output as a command value for the duty ratio δ / T of the switching drive U of the primary side full bridge circuit 22. The duty ratio δ / T increases as the differential pressure between the target voltage at the input / output port B and the current voltage increases (ie, approaches 100%). In this case, since the switching elements 30a to 36a of the primary side full bridge circuit 22 are driven at the duty ratio δ / T or (T−δ) / T, respectively, the primary side conversion circuit 16 is connected to the input / output port. Depresses the voltage of A and outputs it to the input / output port B.

  On the other hand, when the gain constant β is set to “0” and the gain constant α is set to “1”, the duty ratio setting unit 120 sets the differential pressure between the target voltage of the input / output port A and the current voltage. The inverse value of the corresponding value is output as a command value for the duty ratio δ / T of the switching drive U of the primary side full bridge circuit 22. The duty ratio δ / T decreases as the differential pressure between the target voltage of the input / output port A and the current voltage increases (that is, approaches 0%). In this case, since the switching elements 30a to 36a of the primary side full bridge circuit 22 are driven at the duty ratio δ / T or (T−δ) / T, respectively, the primary side conversion circuit 16 is connected to the input / output port. The boosting function of boosting the voltage of B and outputting it to the input / output port A is exhibited.

  FIG. 4 is a flowchart of an example of a control routine executed by the control unit 14 in the power conversion apparatus 10 of the present embodiment. FIG. 5 shows an operation time chart of an example in the power conversion apparatus 10 of the present embodiment.

  In the present embodiment, the control unit 14 performs step-down control from the input / output port C to the input / output ports A and B because the current voltage of the input / output port A is lower than the target voltage, and the load 50, 52, 53 and the auxiliary battery 54 are supplied with power, the gain constant α of each variable gain device 144, 148 is initially set to “0”, and the gain constant of each variable gain device 116, 142, 146 is set. β is initially set to “1” (step 100).

  In such setting conditions of the gain constants α and β, the phase difference setting device 100 outputs a value corresponding to the differential pressure between the target voltage of the input / output port A and the current voltage as the command value of the switching phase difference φ. At this time, the command value of the switching phase difference φ is a positive value. When this command value is output, the switching drive U1, V1 of each switching element 30a to 36a of the primary side full bridge circuit 22 of the primary side conversion circuit 16 becomes the secondary side full bridge circuit of the secondary side conversion circuit 18. The power conversion device 10 functions as a DC-DC converter by being delayed with respect to the switching driving U2 and V2 of 60, and the secondary conversion is performed by the magnetic coupling between the primary side conversion circuit 16 and the secondary side conversion circuit 18. The input voltage at the input / output port C of the side conversion circuit 18 is converted and transmitted to the input / output port A of the primary side conversion circuit 16.

  Further, in the setting conditions of the gain constants α and β, the duty ratio setting unit 120 uses the target voltage of the input / output port B and the current value as the command value of the duty ratio δ / T of the switching drive U of the primary side full bridge circuit 22. Outputs a value corresponding to the differential pressure from the voltage. When such a command value is output, when the current voltage at the input / output port B is smaller than the target voltage, the switching drives U1 and V1 of the switching elements 30a to 36a of the primary-side full bridge circuit 22 are the difference. By performing an appropriate duty ratio according to the pressure, the input voltage of the input / output port A is stepped down in the primary side conversion circuit 16 and transmitted to the input / output port B.

  Therefore, according to the present embodiment, the gain constants α and β are maintained in the initial state as described above in a situation where the current voltage of the input / output port A of the primary side conversion circuit 16 is lower than the target voltage. The main battery 90 to the loads 50, 52, 53 and the auxiliary battery 54 by step-down control from the input / output port C of the secondary conversion circuit 18 to the input / output ports A and B of the primary conversion circuit 16. It is possible to supply power.

  Further, the control unit 14 determines whether or not the voltage (current voltage) of the input / output port A is lower than the specified value γ during the step-down control from the input / output port C to the input / output ports A and B (step) 110). The specified value γ is the lowest voltage that can occur during the execution of the step-down control when the power conversion device 10 is normal, that is, when an abnormal failure has not occurred in the secondary side conversion circuit 18. It is set below the target voltage of port A. As a result, when it is determined that the voltage at the input / output port A does not fall below the specified value γ, the process of step 100 is executed again.

  On the other hand, when the control unit 14 determines that the voltage at the input / output port A is lower than the specified value γ, the control unit 14 switches the gain constant α of each of the variable gain devices 144 and 148 from “0” to “1”. In addition, a process of switching the gain constant β of each variable gain device 116, 142, 146 from “1” to “0” is executed (step 120), and system abnormality (specifically, the secondary side conversion circuit 18) A process of notifying a vehicle user or the like by a warning buzzer or warning display is executed (step 130).

  When the gain constants α and β are changed as described above, the phase difference setting device 100 outputs a command value of zero switching phase difference φ. When such a zero command is issued, the switching drive U1, V1 of the primary side full bridge circuit 22 of the primary side conversion circuit 16 and the switching drive U2, V2 of the secondary side full bridge circuit 60 of the secondary side conversion circuit 18 Are performed at the same timing, the voltage conversion between the primary side conversion circuit 16 and the secondary side conversion circuit 18 is stopped.

  When the gain constants α and β are changed, the duty ratio setting unit 120 sets the target value of the input / output port A as the command value of the duty ratio δ / T of the switching drive U of the primary side full bridge circuit 22. The inverse value of the value corresponding to the differential pressure between the voltage and the current voltage is output. When such a command value is output, when the current voltage of the input / output port A is smaller than the target voltage, the switching drives U1 and V1 of the switching elements 30a to 36a of the primary side full bridge circuit 22 are the difference. By performing with an appropriate duty ratio corresponding to the pressure, the input voltage of the input / output port B is boosted and converted to the input / output port A in the primary side conversion circuit 16.

  Therefore, according to the present embodiment, since the current voltage of the input / output port A of the primary side conversion circuit 16 is lower than the target voltage, the input / output port C of the secondary side conversion circuit 18 is connected to the primary side conversion circuit 16. When the step-down control to the input / output ports A and B is being executed, if the voltage of the input / output port A of the primary side conversion circuit 16 falls below the specified value γ, the gain constants α, β in the control unit 14 Is changed from the auxiliary battery 54 connected to the input / output port B to the input / output port A by the boost control from the input / output port B of the primary side conversion circuit 16 to the input / output port A. It is possible to supply power to the load 50.

  That is, in this embodiment, since the current voltage at the input / output port A of the primary side conversion circuit 16 is lower than the target voltage, the input of the primary side conversion circuit 16 from the input / output port C of the secondary side conversion circuit 18 is reduced. When the step-down control to the output ports A and B is being executed, as long as the voltage at the input / output port A of the primary side conversion circuit 16 is equal to or higher than the specified value γ, the step-down control from the main battery 90 is performed as usual. While power can be supplied to the loads 50, 52, 53 and the auxiliary battery 54, when the voltage at the input / output port A of the primary side conversion circuit 16 falls below the specified value γ, the primary side conversion circuit 16. By the step-up control from the input / output port B to the input / output port A, power can be supplied from the auxiliary battery 54 connected to the input / output port B to the load 50 connected to the input / output port A.

  In this regard, according to the power conversion device 10 of the present embodiment, during the step-down control from the input / output port C of the secondary side conversion circuit 18 to the input / output ports A and B of the primary side conversion circuit 16, It is determined that appropriate power transmission between the primary side conversion circuit 16 and the secondary side conversion circuit 18 has become difficult because the voltage at the input / output port A of the secondary side conversion circuit 16 is lower than the specified value γ. Sometimes, power transmission to the input / output port A of the primary side conversion circuit 16 can be continued using the auxiliary battery 54 connected to the input / output port B of the same primary side conversion circuit 16.

  If power transmission to the input / output port A of the primary side conversion circuit 16 is continued using the auxiliary battery 54, the voltage of the input / output port A is returned from the state below the specified value γ toward the target voltage. Therefore, an operable voltage can be supplied to the load 50 connected to the input / output port A. Therefore, according to the power conversion device 10 of the present embodiment, when power transmission from the secondary conversion circuit 18 magnetically coupled to the primary conversion circuit 16 of the power conversion circuit 12 becomes difficult, the primary conversion is performed. The voltage of the input / output port A of the side conversion circuit 16 can be prevented from dropping to zero as shown by the broken line in FIG. 5, and the operation of the load 50 connected to the input / output port A can be continued. .

  Further, in this embodiment, in order to continue the operation of the load 50 connected to the input / output port A when power transmission from the secondary side conversion circuit 18 to the primary side conversion circuit 16 becomes difficult, It is sufficient to change the values of the gain constants α and β in the circuit constituting the control unit 14 between “0” and “1”. In this regard, according to the present embodiment, the secondary side conversion circuit 18 to the primary side conversion circuit 16 can be configured with a simple configuration and simple control logic without adding a special additional circuit and without performing complicated control. It is possible to realize the continuation of the operation of the load 50 when it becomes difficult to transmit power to the power source.

  In the above embodiment, the load 50 is connected to the “load” described in the claims, the input / output port A is connected to the “first input / output port” described in the claims, and the auxiliary battery 54 is connected to the load. In the “first battery” described in the claims, the input / output port B is described in the “second input / output port” described in the claims, and the primary side conversion circuit 16 is described in the claims. In the “first conversion circuit”, the main battery 90 is converted into the “second battery” described in the claims, and the input / output port C is converted into the “third input / output port” described in the claims. The circuit 18 is a “second conversion circuit” described in the claims, and the control unit 14 steps down the voltage of the input / output port C to supply power from the main battery 90 to the load 50 and the auxiliary battery 54. Described in the claims, “First System” The control unit 14 determines whether or not the voltage of the input / output port A is lower than the specified value γ. In the “voltage determination means” described in the claims, the control unit 14 performs the step-down control. The control for supplying power from the auxiliary battery 54 to the load 50 instead of the step-down control during execution corresponds to the “second control” described in the claims.

  In the above-described embodiment, the primary side coil 24 is the “first coil” described in the claims, and the primary side full bridge circuit 22 is the “first full bridge circuit”. The secondary side coil 62 is included in the “second coil” recited in the claims, and the bridge circuit 60 descending on the secondary side is included in the “second full bridge circuit” recited in the claims. In the state where the gain constant α is initially set to “0” and the gain constant β is initially set to “1”, the switching phase difference φ set by the phase difference setting device 100 and the duty ratio setting device 120 are set. In the “first control drive control means” described in the claims, the controller is configured to drive the primary side full bridge circuit 22 and the secondary side full bridge circuit 60 with the duty ratio δ / T set in the above. 14 is the gain constant The primary side full bridge circuit 22 is driven at the duty ratio δ / T set by the duty ratio setting device 120 in a state where α is set to “1” and the gain constant β is set to “0”. This corresponds to “second control drive control means” described in the claims.

  By the way, in the above embodiment, the voltage of the input / output port C of the secondary side conversion circuit 18 is stepped down and connected to the low voltage side primary side conversion circuit 16 from the high voltage side main unit battery 90 or the auxiliary battery. This is applied to a system that supplies power to 54. However, the present invention is not limited to this, and can be applied to a system that boosts the voltage of the low-voltage input / output port and supplies power from the low-voltage battery to the high-voltage load or battery. is there. In such a modification, when the voltage of the input / output port to which the high voltage side load is connected falls below a specified value equal to or lower than the target voltage, instead of supplying power from the low voltage side battery to the load, What is necessary is just to supply electric power to the load.

  Further, in the above embodiment, when the voltage of the input / output port A of the primary side conversion circuit 16 is lower than the specified value equal to or lower than the target voltage, a voltage lower than the target voltage of the input / output port A is output. The present invention is applied to a system that boosts the voltage of the output port B and supplies power to the load 50 connected to the input / output port A. However, the present invention is not limited to this, and when the voltage of the low-voltage input / output port falls below a specified value equal to or lower than the target voltage, a voltage higher than the target voltage of the low-voltage input / output port is output. It is also possible to apply to a system in which the voltage of the input / output port on the high-voltage side is stepped down and power is supplied to the load connected to the input / output port on the low-voltage side.

DESCRIPTION OF SYMBOLS 10 Power converter 12 Power converter circuit 14 Control part 16 Primary side converter circuit 18 Secondary side converter circuit 20 Transformer 22 Primary side full bridge circuit 24 Primary side coil 28,66 Center tap 30-36 Primary side arm Element 40 Primary side positive electrode bus 42 Primary side negative electrode bus 50, 52, 53 Load 54 Auxiliary battery 60 Secondary side full bridge circuit 62 Secondary side coil 70-76 Secondary side arm element 80 Secondary side element Positive electrode bus 82 Secondary negative electrode bus 90 Main battery 100 Phase difference setting device 120 Duty ratio setting device

Claims (3)

A first input / output port provided between a first full bridge circuit including a first coil constituting a center tap type transformer and a positive and negative buses of the first full bridge circuit to which a load is connected. A first conversion circuit having a second input / output port connected between the negative bus of the first full bridge circuit and a center tap of the transformer and connected to the first battery;
Said transformer by magnetically coupling said first converting circuit, provided between the second full bridge circuit including a second coil constituting the transformer, the positive bus and the negative bus of said second full bridge circuit a third output port, wherein the first second, different battery and the battery is connected, a second conversion circuit having,
The first voltage of the first input / output port and the target are set as the first control for reducing or boosting the voltage of the third input / output port to the target voltage and supplying power from the second battery to the load and the first battery. The first full bridge circuit and the second full bridge circuit are driven with a phase difference corresponding to a difference from the voltage and a duty ratio corresponding to a difference between the actual voltage of the second input / output port and the target voltage. A control unit having a first control time drive control means ,
A power conversion device comprising:
Voltage discriminating means for discriminating whether or not the voltage of the first input / output port falls below a predetermined value equal to or lower than a target voltage;
When the voltage determination unit determines that the voltage of the first input / output port is lower than the predetermined value during execution of the first control, the control unit replaces the first control with the first battery. Second control drive control means for driving the first full bridge circuit with a duty ratio according to the difference between the actual voltage of the first input / output port and the target voltage as the second control for supplying power to the load from The power converter characterized by having . The first control drive control means uses the PID value of the difference between the actual voltage of the first input / output port and the target voltage as a phase difference command value, and the actual voltage and the target voltage of the second input / output port. And driving the first full bridge circuit and the second full bridge circuit using the PID value of the difference between the first full bridge circuit and the second full bridge circuit as a duty ratio command value,
The second control drive control means drives the first full bridge circuit using a PID value of a difference between an actual voltage of the first input / output port and a target voltage as a duty ratio command value. Item 4. The power conversion device according to Item 1 . The first control driving control means and the second control driving control means are circuits realized by changing a gain constant in a circuit constituting the control unit, respectively. The power conversion device according to 1 or 2 .

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