DC / DC converter

Abstract

The purpose of the present disclosure is to protect an input-side capacitor at the time of an abnormality. A DC-DC converter according to the present invention comprises a first converter circuit, a second converter circuit, and a switch control circuit. The first converter circuit comprises a first switch and a first inductor. The second conversion circuit comprises a second switch and a second inductor. The first inductor and the second inductor are connected in parallel to each other to an input terminal and the input-side capacitor of the DC-DC converter. The DC-DC converter further comprises a first detection circuit, a second detection circuit, and a stop-determination circuit. The first detection circuit detects a first current flowing through the first inductor. The second detection circuit detects a second current flowing through the second inductor.The stop-determination circuit stops a conversion operation based on the difference between the first current and the second current.

Description

TECHNICAL AREA

[0001] The present invention relates to a DC / DC converter that converts a voltage from a direct current. STATE OF THE ART

[0002] Some DC-DC converters contain an input terminal, an input-side capacitor, converter circuitry, an output terminal, and a switch control circuit. The converter circuitry contains a switch and an inductor. The switch control circuitry controls the voltage conversion operation of the converter circuitry by controlling the switch. Citation list Patent specification

[0003] Patent specification 1: PCT International Publication No. WO2019 / 167271 DISCLOSURE OF THE INVENTION Problems to be solved by the invention

[0004] The inventors focused on the fact that using a predetermined configuration in such a DC-DC converter can lead to the following problems. In this configuration, a first converter circuit and a second converter circuit are connected in parallel to the input terminal and the input-side capacitor. The switching control circuit controls the switching of the first converter circuit without providing feedback on its current value. Similarly, the switching control circuit controls the switching of the second converter circuit without providing feedback on its current value. In other words, the switching control circuit performs open-loop (or feedback-free) control for the voltage conversion operation of both the first and second converter circuits. In this case, the following problems can occur.

[0005] If an abnormality such as an open circuit or other failure occurs in either of the two converter circuits, an impedance imbalance arises between the first and second converter circuits. Due to open-loop control, the current varies between the time current flows through the first and second converter circuits. This increases the range of current fluctuations between the two. As a result of this fluctuation, the current flowing into and out of the input-side capacitor increases. This inflow and outflow generates heat in the input-side capacitor, which can lead to its failure.Therefore, in a case where such an abnormality occurs, it is necessary to detect the abnormality quickly and protect the input-side capacitor.

[0006] However, in a method for detecting abnormalities based on an overcurrent, the abnormality cannot be detected if current repeatedly flows in and out of the input-side capacitor within a region where the overcurrent is not detected. In a method for detecting the temperature of the input-side capacitor using a temperature sensor, the temperature sensor must be installed inside the input-side capacitor, which increases costs.

[0007] The present disclosure was made taking into account the situation described above, and its aim is to protect an input-side capacitor by a suitable method when an abnormality occurs in a DC-DC converter that performs open-loop control during voltage conversion operation. Means to solve the problems

[0008] The DC / DC converter of the present disclosure contains: an input port, an input-side capacitor, a first converter circuit, a second converter circuit, an output port and a switch control circuit, where the first converter circuit includes a first switch and contains a first coil the second converter circuit contains a second switch and a second coil, the first coil and the second coil are connected in parallel to the input terminal and the input-side capacitor, The switch control circuit performs an open-loop control for the voltage conversion operation of the first converter circuit and the second converter circuit by controlling the first switch and the second switch, and Electrical energy, converted to voltage by the voltage conversion process, is output from the output terminal. The DC-DC converter also contains a first detection circuit that detects a first current as a current flowing through the first coil, a second detection circuit that detects a second current as a current flowing through the second coil, and a stop determination circuit that stops the voltage conversion operation based on a difference between the first current and the second current. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a circuit diagram showing a DC-DC converter of a first embodiment; Fig. Figure 2 is a circuit diagram showing a stop-determination circuit; Fig. 3 is a circuit that shows a first state in power operation; Fig. 4 is a circuit that shows a second state in power operation; Fig. Figure 5 is a graph showing the transition of each current during power operation; Fig. Figure 6 is a graph showing the transition of each current when an abnormality occurs in power operation; Fig. Figure 7 is a graph showing the transition of each current before and after the stop control; Fig. 8 is a circuit that shows a first state during recovery; Fig. 9 is a circuit that shows a second state during recovery. Fig. Figure 10 is a graph showing the transition of each stream during recovery; Fig. is a circuit diagram showing a stop-determination circuit of a second embodiment; and Fig. is a graph showing the transition of each current before and after the stop control. PREFERRED IMPLEMENTATION OF THE INVENTION

[0009] The following describes embodiments of the present disclosure with reference to the drawings. It should be noted that the present disclosure is not limited to the following embodiments and can be implemented by suitable modifications within a scope that does not deviate from the essence of the present disclosure. [First embodiment]

[0010] As in Fig. As shown in Figure 1, a DC-DC converter (Dcv) has input terminals Pi+, Pi- and output terminals Po+, Po-. Hereinafter, the positive terminal of the input terminals Pi+, Pi- will simply be referred to as "input terminal Pi+", and the negative terminal will simply be referred to as "input terminal Pi-". Similarly, the positive terminal of the output terminals Po+, Po- will simply be referred to as "output terminal Po+", and the negative terminal will simply be referred to as "output terminal Po-".

[0011] A DC power source Ps is electrically connected to the input terminals Pi+ and Pi-. An amplifier AP for driving a robot Rb, etc., is electrically connected to the output terminals Po+ and Po-.

[0012] The DC-DC converter Dcv further comprises an input-side capacitor Ci, a first converter circuit Tc1, a second converter circuit Tc2, and an output-side capacitor Co. The first converter circuit Tc1 comprises a first upper switch Q1U, a first lower switch Q1D, and a first inductor L1. The second converter circuit Tc2 comprises a second upper switch Q2U, a second lower switch Q2D, and a second inductor L2.

[0013] In the following, the first upper switch Q1U and the first lower switch Q1D will be referred to collectively as "first switches Q1U, Q1D". Similarly, the second upper switch Q2U and the second lower switch Q2D will be referred to collectively as "second switches Q2U, Q2D". The first upper switch Q1U, the first lower switch Q1D, the second upper switch Q2U, and the second lower switch Q2D will be referred to collectively as "respective switches Q1U, Q1D, Q2U, Q2D". The respective switches Q1U, Q1D, Q2U, Q2D are all semiconductor switches, such as transistors.

[0014] One end of the first coil L1 is electrically connected via the first upper switch Q1U to the positive terminal of each of the input terminals Pi+, Pi- and the input-side capacitor Co. Furthermore, one end is electrically connected via the first lower switch Q1D to the negative terminal of each of the input terminals Pi+, Pi-, the input-side capacitor Co, the output-side capacitor Ci, and the output terminals Po+, Po-. The other end of the first coil L1 is electrically connected to the positive terminal of each of the output-side capacitors Co and the output terminals Po+, Po-.

[0015] One end of the second coil L2 is electrically connected via the second upper switch Q2U to the positive terminal of each of the input terminals Pi+, Pi- and the input-side capacitor Co. Furthermore, one end is electrically connected via the second lower switch Q2D to the negative terminal of each of the input terminals Pi+, Pi-, the input-side capacitor Co, the output-side capacitor Ci, and the output terminals Po+, Po-. The other end of the second coil L2 is electrically connected to the positive terminal of each of the output-side capacitors Co and the output terminals Po+, Po-.

[0016] Therefore, the input terminals Pi+, Pi- and the input-side capacitor Ci are electrically connected to the output-side capacitor Co and the output terminals Po+, Po- via the first coil L1 and the second coil L2, which are arranged in parallel. That is, the first coil L1 and the second coil L2 are connected in parallel to the input terminals Pi+, Pi- and the input-side capacitor Ci.

[0017] In the present embodiment, each of the switches Q1U, Q1D, Q2U, and Q2D has a parasitic diode. That is, the first upper switch Q1U has a parasitic diode that allows current to flow from the first coil L1 to the input-side capacitor Ci and to the input terminal Pi+. The second upper switch Q2U has a parasitic diode that allows current to flow from the second coil L2 to the input-side capacitor Ci and to the input terminal Pi+. The first lower switch Q1D has a parasitic diode that allows current to flow from the output-side capacitor Co and the output terminal Po- to the first coil L1. The second lower switch Q2D has a parasitic diode that allows current to flow from the output-side capacitor Co and the output terminal Po- to the second coil L2.

[0018] However, instead of the configuration described above, a semiconductor switch without a parasitic diode, such as an IGBT, can be used as the respective switches Q1U, Q1D, Q2U, Q2D, and a freewheeling diode can be electrically connected in parallel to the respective switches Q1U, Q1D, Q2U, Q2D.

[0019] In the following, a current flowing through the input terminal Pi+ from the DC source Ps is referred to as the "input current Ii". A current flowing from an electrical connection point ei between the input terminal Pi+ and the input-side capacitor Ci to an electrical connection point eu between the first upper switch Q1U and the second upper switch Q2U is referred to as the "input-side current Iis". A current flowing through the first upper switch Q1U is referred to as the "first upper current Iq1u", and a current flowing through the first lower switch Q1D is referred to as the "first lower current Iq1d". A current flowing through the second upper switch Q2U is referred to as the "second upper current Iq2u", and a current flowing through the second lower switch Q2D is referred to as the "second lower current Iq2d".A current flowing through the first coil L1 is called "first current It1", and a current flowing through the second coil L2 is called "second current It2".

[0020] The DC-DC converter Dcv also includes a switching control circuit Sc. The switching control circuit Sc controls the first switches Q1U and Q1D without providing feedback on the value of the first current It1. Furthermore, the switching control circuit Sc controls the second switches Q2U and Q2D without providing feedback on the value of the second current It2. That is, the switching control circuit Sc performs open-loop control for voltage conversion operation of the first converter circuit Tc1 and the second converter circuit Tc2.

[0021] With such an open-loop control, during power operation, the voltage of energy applied to the input terminals Pi+, Pi- is stepped down and then output at the output terminals Po+, Po-. Conversely, during recovery (or regeneration), the voltage of energy applied to the output terminals Po+, Po- is stepped up and then, contrary to the representation in Fig. 1 is output at the input ports Pi+, Pi-.

[0022] The following describes how in Fig. Figure 3 shows a state in which the first upper switch Q1U and the second lower switch Q2D are turned on, and the first lower switch Q1D and the second upper switch Q2U are turned off, referred to as the "first state s1". Furthermore, as shown in Fig. Figure 4 shows a state in which the first upper switch Q1U and the second lower switch Q2D are off, and the first lower switch Q1D and the second upper switch Q2U are on, referred to as the "second state s2". It should be noted that, for better identification of the on and off states of the respective switches Q1U, Q1D, Q2U, Q2D, which are semiconductor switches, are shown in the diagram. Fig. 3 and Fig. 4 are indicated by the symbol of a mechanical switch. The same applies to those described later. Fig. 8 and Fig. 9.

[0023] During power operation, in a state where current flows from the input terminal Pi+ to the output terminal Po+ Fig. When current flows, the switch control circuit Sc alternately switches between the first state s1 and the second state s1. Fig. 3 and the second state s2 in Fig. 4 µm. In the first state s1 in Fig. 3. The first current It1 increases and the second current It2 decreases. In the second state s2, which is in Fig. As shown in Figure 4, the first current It1 decreases and the second current It2 increases. As in Fig. As shown in Figure 5, the first current It1 and the second current It2 change by shifting their phases 180° relative to each other.

[0024] As in Fig. As shown in Figure 5, the first current It1 is the sum of the first upper current Iq1u in the first state s1 and the first lower current Iq1d in the second state s2. The second current It2 is the sum of the second lower current Iq2d in the first state s1 and the second upper current Iq2u in the second state s2.

[0025] The input-side current Iis is the sum of the first upper current Iq1u in the first state s1 and the second upper current Iq2u in the second state s2. That is, the input-side current Iis is the sum of the first current It1 in the first state s1 and the second current It2 in the second state s2. This is related to the problems that the present embodiment is intended to solve, as described later.

[0026] During the recovery, against the direction of the in Fig. As indicated by the arrows shown, in a state where current flows from output terminal Po+ to input terminal Pi+, the switch control circuit Sc alternately switches between the first state s1, which is in Fig. 8 is shown, and the second state s2, which is in Fig. Figure 9 shows that during the recovery process, the first current It1 and the second current It2 also merge into each other by shifting their phases 180° relative to each other. Fig. 10 shows.

[0027] In the present embodiment, during power operation and recovery, the time during which the first state s1 is maintained and the time during which the second state s2 is maintained are equal. Thus, the duty cycle of the respective switches Q1U, Q1D, Q2U, Q2D is approximately 50%. More precisely, the duty cycle of the respective switches Q1U, Q1D, Q2U, Q2D is shorter than 50% by one dead time.

[0028] It should be noted that the dead time described here is the point in time at which both the upper and lower switches are instantaneously switched off when switching between the first state s1 and the second state s2. During the dead time in power operation, as described in Fig. As shown in Figure 1, a current flows through each lower switch Q1D, Q2D due to the parasitic diode of each lower switch Q1D, Q2D. On the other hand, during the dead time in the recovery phase, a current flows in the opposite direction to the current in Figure 1. Fig. 1. A current flows through each upper switch Q1U, Q2U due to the parasitic diode of each upper switch Q1U, Q2U.

[0029] Since the duty cycle of the respective switches Q1U, Q1D, Q2U, Q2D is approximately 50%, during the operation in Fig. In the power operation shown in section 1, a voltage applied to the input terminals Pi+, Pi- is transformed down to approximately half its original value and then output from the output terminals Po+, Po-. On the other hand, during recuperation, where a current flows in the opposite direction to the current in Fig. 1 flows, a voltage applied to the output terminals Po+, Po is increased to approximately double the current and then output from the input terminals Pi+, Pi-.

[0030] Next, the problems that the present embodiment is intended to solve will be described.

[0031] If in one of the in Fig. If an abnormality such as an open circuit or other failure occurs in the first converter circuit Tc1 or the second converter circuit Tc2 shown in Figure 1, an imbalance arises between the impedance of the first converter circuit Tc1 and the impedance of the second converter circuit Tc2. At this point, due to the open-loop control, the magnitudes of the first current It1 and the second current It2 can differ from each other, as shown in Figure 1. Fig. 6 shown.

[0032] As described above, the input current Iis is the sum of the first current It1 in the first state s1 and the second current It2 in the second state s2. Therefore, if the magnitudes of the first current It1 and the second current It2 differ from each other, as in Fig. As shown in Figure 6, the fluctuation range ΔIis of the input-side current Iis is larger than in the normal state, which is shown in Fig. 5 is shown. Due to the in Fig. In the fluctuation range ΔIis shown in Figure 6, the magnitude of the current flowing into and out of the input-side capacitor Ci increases. This inflow and outflow generates heat in the input-side capacitor Ci, which can lead to its failure. Therefore, if such an abnormality occurs, it is necessary to detect it quickly and protect the input-side capacitor Ci.

[0033] To solve the problems described above, the DC-DC converter Dcv further includes a first detection circuit A1, a second detection circuit A2, and a stop-determination circuit Jc, as shown in Fig. 1 shown.

[0034] The first detection circuit A1 detects a current in a section electrically connected in series with the first coil L1 to detect the first current It1 and outputs a "first voltage V1" based on the magnitude of the detected first current It1. The second detection circuit A2 detects a current in a section electrically connected in series with the second coil L2 to detect the second current It2 and outputs a second voltage V2 based on the magnitude of the detected second current It2.

[0035] The stop-determination circuit Jc outputs a stop signal Vb to the switch control circuit Sc, based on a difference between the first voltage V1 and the second voltage V2. The stop signal Vb signals the termination of the voltage conversion operation. In other words, the stop-determination circuit Jc halts the voltage conversion operation based on a difference between the first current It1 and the second current It2.

[0036] Next, the details of the stop-determination circuit Jc will be described with reference to Fig. 2 described. The stop-determination circuit Jc contains a first to third operational amplifier Ap1 to Ap3, a first to ninth resistor R1 to R9 as electrical resistors, a first and second diode Do1, Do2 and a constant voltage source Pth.

[0037] An output terminal of the first detection circuit A1 is electrically connected via the first resistor R1 to an inverting input terminal of the first operational amplifier Ap1, and via the fourth resistor R4 to a non-inverting input terminal of the second operational amplifier Ap2. An output terminal of the second detection circuit A2 is electrically connected via the second resistor R2 to a non-inverting input terminal of the first operational amplifier Ap1, and via the third resistor R3 to an inverting input terminal of the second operational amplifier Ap2. The non-inverting input terminal of the first operational amplifier Ap1 is electrically connected to ground via the fifth resistor R5. The non-inverting input terminal of the second operational amplifier Ap2 is electrically connected to ground via the sixth resistor R6.

[0038] An output terminal of the first operational amplifier Ap1 is electrically connected to an anode electrode of the first diode Do1. A cathode electrode of the first diode Do1 is electrically connected via the seventh resistor R7 to the inverting input terminal of the first operational amplifier Ap1 and is electrically connected to a non-inverting input terminal of the third operational amplifier Ap3.

[0039] An output terminal of the second operational amplifier Ap2 is electrically connected to an anode electrode of the second diode Do2. A cathode electrode of the second diode Do2 is electrically connected via the eighth resistor R8 to the inverting input terminal of the second operational amplifier Ap2 and is electrically connected to the non-inverting input terminal of the third operational amplifier Ap3.

[0040] The non-inverting input terminal of the third operational amplifier Ap3 is electrically connected to ground via the ninth resistor R9. The constant voltage source Pth is electrically connected to an inverting input terminal of the third operational amplifier Ap3, and a threshold voltage Vth is applied there.

[0041] With the circuit configuration described above, the first operational amplifier Ap1 outputs a "first differential voltage ΔV1" as a voltage based on the value (V1 - V2) of the first voltage V1 minus the second voltage V2. The second operational amplifier Ap2, on the other hand, outputs a "second differential voltage ΔV2" as a voltage with an output value (V2 - V1) of the second voltage V2 minus the first voltage V1. The third operational amplifier Ap3 outputs a voltage as a stop signal Vb when the larger of the two differential voltages, i.e., either the first differential voltage ΔV1 or the second differential voltage ΔV2, is greater than the threshold voltage Vth.

[0042] As a result of the process described above, the stop-determination circuit Jc outputs the stop signal Vb when the absolute value of the difference (It1 - It2) between the value of the first current It1 and the value of the second current It2 is greater than a threshold value Ith, as shown in Fig. 7 shown.

[0043] Upon receiving the stop signal Vb, the process is carried out in Fig. The switch control circuit shown in Figure 1 is a stop control. This stop control is used to stop the voltage conversion operation by controlling the respective switches Q1U, Q1D, Q2U, and Q2D. More precisely, the stop control is implemented, for example, as follows.

[0044] That is, if the stop signal Vb is triggered during the operation, Fig. 3 and Fig. When power operation 4 is received, the switch control circuit Sc fixes the respective switches Q1U, Q1D, Q2U, Q2D in the OFF position via the stop control. In this case as well, current flows through the first lower switch Q1D and the second lower switch Q2D via the parasitic diodes.

[0045] The stop control described above maintains the reverse current flow in a closed circuit containing the first lower switch Q1D and the first coil L1, and in a closed circuit containing the second lower switch Q2D and the second coil L2. As a result, the first current It1 and the second current It2 drop to zero, and the voltage conversion operation stops, as shown in Fig. 7 shown.

[0046] If, however, during the in the Fig. 8 and Fig. In Figure 9, when the recovery signal Vb is received, the switch control circuit Sc locks the respective switches Q1U, Q1D, Q2U, and Q2D to OFF via the stop control. In this case as well, current flows through the parasitic diodes in the first upper switch Q1U and the second upper switch Q2U. Due to the stop control described above, the first current It1 and the second current It2 drop to zero, similar to the case during power operation, and the voltage conversion operation is stopped.

[0047] As in Fig. As shown in Figure 1, an alarm device Nd is provided outside the DC-DC converter Dcv. The stop-determination circuit Jc outputs the stop signal Vb to the alarm device Nd. The alarm device Nd generates an alarm when it receives the stop signal Vb. Such an alarm can be, for example, a screen display, an audible alarm, or both.

[0048] The following is a summary of the configuration and effects of the present embodiment.

[0049] The in Fig. The switch control circuit Sc shown performs the open-loop control of the voltage conversion operation of the first converter circuit Tc1 and the second converter circuit Tc2 by controlling the respective switches Q1U, Q1D, Q2U, and Q2D. The first detection circuit A1 detects the first current It1 flowing through the first coil L1. The second detection circuit A2 detects the second current It2 flowing through the second coil L2. The stop-determination circuit Jc stops the voltage conversion operation based on the difference between the first current It1 and the second current It2.

[0050] Thus, during an abnormality where the value of the first current It1 and the value of the second current It2 differ from each other, i.e., an abnormality where one in the Fig. The current flowing in and out of capacitor Ci shown on the input side is large, the voltage conversion operation as shown in Fig. Figure 7 shows that the process can be stopped. This allows the heat generation of the input-side capacitor Ci due to such inflow and outflow to be suppressed, thus protecting the input-side capacitor Ci. As described above, according to the present embodiment, if an abnormality occurs in the DC-DC converter, which performs open-loop control of the voltage conversion operation, the input-side capacitor Ci can be protected by a suitable method.

[0051] Both during power operation and during recovery, the in Fig. The stop-determination circuit Jc shown in Figure 1 controls the voltage conversion operation based on the difference between the first current It1 and the second current It2. Thus, the input-side capacitor Ci can be protected during both power operation and recovery if an abnormality occurs.

[0052] The stop-determination circuit Jc outputs the stop signal Vb to the switching control circuit Sc, based on the difference between the first current It1 and the second current It2. Upon receiving the stop signal Vb, the switching control circuit Sc stops the voltage conversion operation by controlling the respective switches Q1U, Q1D, Q2U, and Q2D. Thus, the voltage conversion operation can be stopped with a simple configuration that only outputs the stop signal Vb to the switching control circuit Sc.

[0053] As in Fig. As shown in Figure 2, the first detection circuit A1 outputs the first voltage V1 based on the magnitude of the first current It1. The second detection circuit A2 outputs the second voltage V2 based on the magnitude of the second current It2. The first operational amplifier Ap1 outputs the first differential voltage ΔV1 based on the value (V1 - V2) of the first voltage (V1) minus the second voltage V2. The second operational amplifier Ap2 outputs the second differential voltage ΔV2 based on the value (V2 - V1) of the second voltage (V2) minus the first voltage V1. The third operational amplifier Ap3 outputs the voltage as a stop signal Vb when the greater of the first differential voltage ΔV1 and the second differential voltage ΔV2 is greater than the threshold voltage Vth. Thus, the stop-determination circuit Jc can be implemented with a simple configuration using the three operational amplifiers Ap1, Ap2, and Ap3.

[0054] Consequently, the stop-determination circuit Jc stops the voltage conversion operation under the condition that the absolute value of the difference (It1 - It2) between the value of the first current It1 and the value of the second current It2 is greater than the threshold Ith, as in Fig. Figure 7 shows that if the absolute value of such a difference (It1 - It2) is greater than the threshold value Ith, the voltage conversion operation can be quickly stopped.

[0055] As in Fig. As shown in Figure 1, the stop-determination circuit Jc outputs the stop signal Vb as a predetermined signal not only to the control circuit Sc, but also to the alarm device Nd. The alarm device Nd generates an alarm when it receives the stop signal Vb. Thus, a worker or similar person can detect an abnormality in the DC-DC converter Dcv based on the alarm. [Second embodiment]

[0056] Next, a second embodiment will be described with reference to the Fig. 11 and Fig. 12. The present embodiment is described with emphasis on the differences from the first embodiment, whereby descriptions of points that are identical or similar to those of the first embodiment are omitted where appropriate.

[0057] The in Fig. The stop determination circuit Jc of the present embodiment shown in Figure 11 outputs the stop signal under the condition that not the absolute value of the difference (It1 - It2) itself between the first current value It1 and the second current value It2, but the absolute value of a value that increases by accumulation of such a difference, is greater than the threshold value.

[0058] In particular, the stop-determination circuit Jc of the present embodiment further comprises a first capacitor C1 and a second capacitor C2. The output terminal of the first operational amplifier Ap1 is electrically connected to the inverting input terminal of the first operational amplifier Ap1 via the seventh resistor R7 and the first capacitor C1, which are connected in parallel. It should be noted that the seventh resistor R7 can be interpreted as the "first feedback resistor." The output terminal of the second operational amplifier Ap2 is electrically connected to the inverting input terminal of the second operational amplifier Ap2 via the eighth resistor R8 and the second capacitor C2, which are connected in parallel. It should be noted that the eighth resistor R8 can be interpreted as the "second feedback resistor."

[0059] Therefore, the first differential voltage ΔV1 increases with the accumulation of the value (V1 - V2) of the first voltage V1 minus the second voltage V2. Conversely, the second differential voltage ΔV2 increases with the accumulation of the value (V2 - V1) of the second voltage V2 minus the first voltage V1. The third operational amplifier Ap3 outputs the stop signal Vb when the greater of the first differential voltage ΔV1 and the second differential voltage ΔV2 exceeds the threshold voltage Vth.

[0060] As a result of the process described above, the stop-determination circuit Jc stops the voltage conversion operation if not the absolute value of the difference (It1 - It2) itself between the first current value It1 and the second current value It2, but rather the absolute value that increases with the accumulation of such a difference (It1 - It2), exceeds the threshold. Thus, as in Fig. As shown in Figure 12, the timing of the voltage conversion operation stoppage is delayed compared to the first embodiment. Consequently, even a detrimental effect of the voltage conversion operation stopping when the absolute value of the difference (It1 - It2) is temporarily greater than the threshold value Ith due to a disturbance or the like can be reduced.

[0061] Furthermore, the present embodiment can be implemented with a simple configuration by simply adding the first capacitor C1 and the second capacitor C2, as shown in Fig. 11 shown, to the state of the first embodiment, which is in Fig. As shown in Figure 2, the circuit for determining the stop-determination circuit Jc can be implemented with a simple configuration using the three operational amplifiers Ap1, Ap2, Ap3 and the two capacitors C1, C2. [Other embodiments]

[0062] The embodiments described above can be modified, for example, as follows. The DC-DC converter can be replaced by a converter that can convert a voltage not in both directions of power operation and recuperation, but only in one direction of power operation. In this case, the first lower switch and the second lower switch can each be replaced by a diode.

[0063] Instead of the stop-determination circuit Jc, which outputs the stop signal Vb to the switch control circuit Sc, the stop-determination circuit Jc can be configured to switch the respective switches Q1U, Q1D, Q2U, Q2D directly to OFF.

[0064] According to the embodiments described above, DC voltage converters of the following additional notes 1 to 9 can be implemented. [Additional Note 1]

[0065] A DC-DC converter (Dcv) includes an input terminal (Pi+, Pi-), an input-side capacitor (ci), a first converter circuit (Tc1), a second converter circuit (Tc2), an output terminal (Po+, Po-) and a switch control circuit (Sc), wherein the first converter circuit (Tc1) includes a first switch (Q1U, Q1D) and a first inductor (L1), the second converter circuit (Tc2) contains a second switch (Q2U, Q2D) and a second coil (L2), the first coil (L1) and the second coil (L2) are connected in parallel to the input terminal (Pi+, Pi-) and to the input-side capacitor (Ci), the switch control circuit (Sc) performs an open-loop control for voltage conversion operation of the first converter circuit (Tc1) and the second converter circuit (Tc2) by controlling the first switch (Q1U, Q1D) and the second switch (Q2U, Q2D), and Electrical energy, converted to voltage by the voltage conversion process, is output from the output terminals (Po+, Po-). The DC-DC converter (Dcv) also contains a first detection circuit (A1) that detects a first current (It1) as a current flowing through the first coil (L1), a second detection circuit (A2) that detects a second current (It2) as a current flowing through the second coil (L2), and a stop-determination circuit (Jc) that stops the voltage conversion operation based on a difference between the first current (It1) and the second current (It2). [Additional Note 2]

[0066] In the DC-DC converter described in additional note 1 The first switch (Q1U, Q1D) contains a first upper switch (Q1U) and a first lower switch (Q1D), the second switch (Q2U, Q2D) contains a second upper switch (Q2U) and a second lower switch (Q2D), one end of the first coil (L1) is electrically connected via the first upper switch (Q1U) to a positive terminal of each input terminal (Pi+, Pi-) and the input-side capacitor (Ci), and via the first lower switch (Q1D) to a negative terminal of each input terminal (Pi+, Pi-) and the input-side capacitor (Ci), and the output terminal (Po+, Po-) is electrically connected via the first lower switch (Q1D), and one end of the second coil (L2) is electrically connected via the second upper switch (Q2U) to a positive terminal of each input terminal (Pi+, Pi-) and the input-side capacitor (Ci), and via the second lower switch (Q2D) to the negative terminal of each Input port (Pi+, Pi-),The input capacitor (Ci) and the output terminal (Po+, Po-) are electrically connected via the second lower switch (Q2D). [Additional Note 3]

[0067] In the DC-DC converter (DCV) described in additional note 1 or 2 During power operation, the DC-DC converter (DCV) converts the voltage of the electrical energy input to the input terminal (Pi+, Pi-) and outputs the electrical energy at the output terminal (Po+, Po-), and during recuperation, it converts the voltage of the electrical energy input to the output terminal (Po+, Po-) and outputs the electrical energy at the input terminal (Pi+, Pi-), and The stop-determination circuit (Jc) stops the voltage conversion operation based on the difference between the first current (It1) and the second current (It2) both during power operation and during recovery. [Additional Note 4]

[0068] In the DC-DC converter (DCV) described in one of the additional notes 1 to 3 The stop determination circuit (Jc) outputs a predetermined stop signal (Vb) to the switch control circuit (Sc) based on the difference, and Upon receiving the stop signal (Vb), the switch control circuit (Sc) stops the voltage conversion operation by controlling the first switch (Q1U, Q1D) and the second switch (Q2U, Q2D). [Additional Note 5]

[0069] In the DC-DC converter (Dvc) described in additional note 4 The first detection circuit (A1) outputs a first voltage (V1) based on the magnitude of the first current (It1), the second detection circuit (A2) outputs a second voltage (V2) based on the magnitude of the second current (It2), and contains the stop determination circuit (Jc) a first operational amplifier (Ap1) that outputs a first differential voltage (ΔV1) based on a value (V1 - V2) of the first voltage (V1) minus the second voltage (V2), a second operational amplifier (Ap2) that outputs a second differential voltage (ΔV2) based on a value (V2 - V1) of the second voltage (V2) minus the first voltage (V1), and a third operational amplifier (Ap3) that outputs a voltage as a stop signal (Vb) when the larger of the first differential voltage (ΔV1) and the second differential voltage (ΔV2) greater than a Threshold voltage (Vth) is. [Additional Note 6]

[0070] In the DC-DC converter (DCV) described in one of the additional notes 1 to 5, the stop-determination circuit stops the Voltage conversion operation under the condition that the absolute value of a difference (It1 - It2) between the value of the first current (It1) and the value of the second current (It2) is greater than a threshold value (Ith). [Additional Note 7]

[0071] In the DC-DC converter (DCV) described in one of the additional notes 1 to 5 The stop-determination circuit stops the Voltage conversion operation under the condition that the absolute value of a value that increases by accumulation of a difference (It1 - It2) between the value of the first current (It1) and the value of the second current (It2) is greater than a threshold value. [Additional Note 8]

[0072] In the DC-DC converter (DCV) described in additional note 5 The stop-determination circuit stops the Voltage conversion operation under the condition that the absolute value of a value that increases by accumulation of a difference (It1 - It2) between the value of the first current (It1) and the value of the second current (It2) is greater than a threshold value, An output terminal of the first operational amplifier (Ap1) is electrically connected to an inverting input terminal of the first operational amplifier (Ap1) via a first feedback resistor (R7) and a first capacitor (C1) connected in parallel, and an output terminal of the second operational amplifier (Ap2) is electrically connected to an inverting input terminal of the second operational amplifier (Ap2) via a second feedback resistor (R8) and a second capacitor (C2) connected in parallel. [Additional Note 9]

[0073] In the DC-DC converter (DCV) described in one of the additional notes 1 to 8 When the voltage conversion operation stops, the stop-determination circuit (Jc) outputs a predetermined signal (Vb) to a predetermined alarm device (Nd), and the alarm device (Nd) generates an alarm when it receives the signal (Vb). EXPLANATION OF REFERENCE SYMBOLS A1 first detection circuit A2 second detection circuit Ap1 first operational amplifier Ap2 second operational amplifier Ap3 third operational amplifier C1 first capacitor C2 second capacitor Ci input-side capacitor DC-DC converter It1 first current It2 second stream Ith threshold JC stop-determination circuit L1 first coil L2 second coil Nd alarm device Pi+ input port Pi input port Po+ output port Po output port Q1U first upper switch (first switch) Q1D first lower switch (first switch) Q2U second upper switch (second switch) Q2D second lower switch (second switch) R7 seventh resistor (first feedback resistor) R8 eighth resistor (second feedback resistor) Sc switch control circuit Tc1 first converter circuit Tc2 second converter circuit V1 first voltage V2 second voltage Vb Stop signal (predetermined signal) Vth threshold voltage ΔV1 first differential voltage ΔV2 second differential voltage QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2019 / 167271

[0003]

Claims

[1] DC / DC converter comprising an input terminal, an input-side capacitor, a first converter circuit, a second converter circuit, an output terminal, and a switch control circuit; wherein the first converter circuit contains a first switch and a first coil, the second converter circuit contains a second switch and a second coil, the first coil and the second coil are connected in parallel to the input terminal and the input-side capacitor, The switch control circuit performs an open-loop control of a voltage conversion operation of the first converter circuit and the second converter circuit by controlling the first switch and the second switch, and Electrical energy that has been converted to voltage by the voltage conversion operation is output from the output terminal. The DC / DC converter includes: a first detection circuit that detects a first current as a current flowing through the first coil; a second detection circuit that detects a second current as a current flowing through the second coil; and a stop-determination circuit that stops the voltage conversion operation based on a difference between the first current and the second current. [2] DC-DC converter according to claim 1, wherein the first switch contains a first upper switch and a first lower switch the second switch contains a second upper switch and a second lower switch one end of the first coil is electrically connected to a positive terminal of each of the input terminal and the input-side capacitor via the first upper switch, and electrically connected to a negative terminal of each of the input terminal, the input-side capacitor and the output terminal via the first lower switch, and one end of the second coil is electrically connected to the positive terminal of each of the input terminal and the input-side capacitor via the second upper switch, and electrically connected to the negative terminal of each of the input terminal, the input-side capacitor and the output terminal via the second lower switch. [3] DC-DC converter according to claim 1 or 2, wherein During power operation, the DC-DC converter converts a voltage of electrical energy that is input to the input terminal and outputs the electrical energy from the output terminal, and during recuperation, it converts a voltage of electrical energy that is input to the output terminal and outputs the electrical energy from the input terminal. The stop-determination circuit stops the voltage conversion operation based on the difference between the first current and the second current, both during power operation and during recovery. [4] DC-DC converter according to any one of claims 1 to 3, wherein The stop determination circuit outputs a predetermined stop signal to the switch control circuit based on the difference and Upon receiving the stop signal, the switch control circuit stops the voltage conversion operation by controlling the first switch and the second switch. [5] DC-DC converter according to claim 4, wherein The first detection circuit outputs a first voltage as a voltage based on the magnitude of the first current, The second detection circuit outputs a second voltage based on the magnitude of the second current, and The stop-determination circuit includes a first operational amplifier that outputs a first differential voltage based on a value of the first voltage minus the second voltage, a second operational amplifier that outputs a second differential voltage based on a value of the second voltage minus the first voltage, and a third operational amplifier that outputs a voltage as the stop signal under the condition that a greater of the first differential voltage and the second differential voltage is greater than a threshold voltage. [6] DC voltage converter according to any one of claims 1 to 5, wherein the stop-determination circuit stops the voltage conversion operation under the condition that an absolute value of a difference between a value of the first current and a value of the second current is greater than a threshold value. [7] DC voltage converter according to any one of claims 1 to 5, wherein the stop-determination circuit stops the voltage conversion operation under the condition that an absolute value of a value which increases with an accumulation of a difference between a value of the first current and a value of the second current is greater than a threshold value. [8] DC-DC converter according to claim 5, wherein The stop-determination circuit stops the voltage conversion operation under the condition that an absolute value of a value that increases with an accumulation of a difference between a value of the first current and a value of the second current is greater than a threshold value. an output terminal of the first operational amplifier is electrically connected to an inverting input terminal of the first operational amplifier via a first feedback resistor and a first capacitor, which are provided in parallel, and An output terminal of the second operational amplifier is electrically connected to an inverting input terminal of the second operational amplifier via a second feedback resistor and a second capacitor, which are provided in parallel. [9] DC-DC converter according to any one of claims 1 to 8, wherein The stop-determination circuit outputs a predetermined signal to a predetermined alarm device when the voltage conversion operation stops, and The alarm device generates an alarm when it receives the signal.

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