Power converter

Abstract

To provide a power conversion device that does not generate induced voltage and can reduce losses. [Solution] The power converter 100 has two primary transformers Lp1 and Lp2 that are magnetically coupled to two circuits B and C on the secondary side, respectively, with one end of each being electrically connected to input / output terminals 1 and 2, while the other ends of the two primary transformers Lp1 and Lp2 are electrically connected to different switching elements Sa1, Sa2, Sb1, and Sb2, respectively.

Description

Technical Field

[0001] This disclosure relates to a power conversion device.

Background Art

[0002] Patent Document 1 discloses a power conversion device having a filter circuit and an inductor circuit using a winding of a transformer in a circuit that includes a first port and a second port as input / output ports and exchanges power between the ports using a transformer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a conventional power conversion device, in the case of a multi-output DCDC converter having two outputs for one input, it is conceivable to magnetically couple a primary transformer connected in parallel to two different secondary circuits respectively.

[0005] However, in a multi-output DCDC converter having two outputs for one input, since the primary transformers are in parallel, even when one of the secondary circuits is stopped, current flows through the primary transformer magnetically coupled to the stopped secondary circuit, causing an induced voltage to be generated on the secondary side as well, resulting in losses, and there is room for improvement.

[0006] This disclosure has been made in view of the above, and an object thereof is to provide a power conversion device in which no induced voltage is generated and losses can be reduced.

Means for Solving the Problems

[0007] The power conversion device according to this disclosure is a power conversion device capable of exchanging power between a primary side and a secondary side using a transformer, wherein one end of each of two primary side transformers, which are magnetically coupled to two circuits on the secondary side, is electrically connected to input / output terminals, while the other ends of the two primary side transformers are electrically connected to different switching elements. [Effects of the Invention]

[0008] According to this disclosure, the effect is that no induced voltage is generated, and losses can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing the configuration of a power conversion device according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a schematic diagram showing magnetic coupling in a power conversion device according to one embodiment of the present disclosure. [Figure 3] Figure 3 is a timing chart of each part in a power conversion device according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0010] A power conversion device according to one embodiment of the present disclosure will be described below with reference to the drawings. Note that the components in the following embodiment include those that are easily substituted or substantially identical to those that are easily substituted by a person skilled in the art.

[0011] [Configuration of the power conversion device] Figure 1 is a schematic diagram showing the configuration of a power converter according to one embodiment of the present disclosure. The power converter 100 shown in Figure 1 comprises a primary circuit A, a secondary circuit B, a secondary circuit C, and a transformer Tr as input / output ports. The power converter 100 exchanges power by magnetically coupling the primary circuit A and the secondary circuit B or C using the transformer Tr. The power converter 100 is configured using a multi-output DC-DC converter with two outputs for one input.

[0012] The input / output terminals 1 and 2 of the primary circuit A are electrically connected to a main battery, which is a DC power source of approximately Vin=350V. Furthermore, the input / output terminals 3 and 4 of the secondary circuit B and the input / output terminals 5 and 6 of the secondary circuit C are electrically connected to an auxiliary battery, which is a DC power source of approximately Vout1=Vout2=12V. Here, the drive motor is electrically connected to the main battery via an inverter. Electrical equipment such as lights, audio, air conditioning, power steering, electric brakes, and various ECUs (Electronic Control Units) are electrically connected to the auxiliary battery.

[0013] Furthermore, the power converter 100 has input / output ports for each of its circuits A, B, and C, allowing them to exchange power with one another. In other words, in the following, "primary side" and "secondary side" do not mean "input side (high voltage side)" and "output side (low voltage side)," but simply mean one end and the other end.

[0014] The primary circuit A comprises a primary transformer Lp1 (primary winding Lp1), which is one of the divided windings of the primary transformer, a capacitor C1, switching elements Sa1 and Sa2, and a primary transformer Lp2 (primary winding Lp2), which is the other of the divided windings of the primary transformer and is arranged in parallel with primary transformer Lp1, a capacitor C2, and switching elements Sb1 and Sb2. Furthermore, primary transformers Lp1 and Lp2 are constructed by winding around a four-legged magnetic core, forming a magnetic path within the core. Additionally, the magnetic flux produced by primary transformers Lp1 and Lp2 is in the same direction. Note that primary transformers Lp1 and Lp2 may be constructed by winding around the same magnetic core.

[0015] Capacitors C1 and C2 are electrically connected in series between input and output terminals 1 and 2. Furthermore, one side (negative terminal) of primary transformers Lp1 and Lp2 is electrically connected to the input voltage Vin (P terminal) of input and output terminals 1 and 2. Additionally, the opposite side (positive terminal) of primary transformer Lp1 is electrically connected to switching elements Sa1 and Sa2. Similarly, the opposite side (positive terminal) of primary transformer Lp2 is electrically connected to switching elements Sb1 and Sb2. In other words, primary transformers Lp1 and Lp2 are arranged in parallel with each other on the primary side.

[0016] The secondary circuit B comprises a secondary transformer Ls1 (secondary winding Ls1), which is one of the divided windings of the secondary transformer; a secondary transformer Ls2 (secondary winding Ls2) arranged in series with secondary transformer Ls1; switching elements S3 and S4; and capacitors C21 and C22 connected in parallel to input and output terminals 3 and 4. Furthermore, the secondary circuit B is electrically connected between switching elements S3 and S4 and capacitors C21 and C22. The secondary circuit B also includes a capacitor C23, which is placed and electrically connected between secondary transformer Ls1 and switching element S3, and between secondary transformer Ls2 and switching element S4.

[0017] The secondary circuit C comprises a secondary transformer Ls3, which is one of the divided windings of the secondary transformer; a secondary transformer Ls4 arranged in series with the secondary transformer Ls3; switching elements S5 and S6; and capacitors C31 and C32 connected in parallel to the input and output terminals 5 and 6. Furthermore, the secondary circuit C is electrically connected between switching elements S5 and S6 and capacitors C31 and C32. The secondary circuit C also includes a capacitor C33, which is placed and electrically connected between the secondary transformer Ls3 and the switching element S5, and between the secondary transformer Ls4 and the switching element S6.

[0018] The secondary circuit B and the secondary circuit C configured as described above can transmit power bidirectionally on the primary and secondary sides in a magnetically non-interfering state. Furthermore, since the secondary circuit B and the circuit C are magnetically non-coupled, it is possible to prevent the circulation current between the secondary circuit B and the circuit C that occurs when they are coupled.

[0019] 〔Operation of the power conversion device〕 Next, the magnetic coupling state and the timing of each part in the power conversion device 100 will be described. FIG. 2 is a diagram schematically showing the magnetic coupling in the power conversion device 100. FIG. 3 is a timing chart of each part in the power conversion device 100.

[0020] As shown in FIGS. 2 and 3, the power conversion device 100 can control the current application of each of the primary transformers Lp1 and Lp2 by performing on / off control of the switching elements Sa1, Sa2 and the switching elements Sb1, Sb2, so that the secondary circuit B or the secondary circuit C can be stopped. For example, when the power conversion device 100 stops the secondary circuit C, it controls the switching elements Sa1, Sa2 to be in the off state and stops the application of current to the primary transformer Lp1, so that no current flows through the primary transformer Lp1 and the secondary circuit C, and the loss can be reduced.

[0021] Furthermore, since the power conversion device 100 can control the current application to the primary transformer Lp1 and the primary transformer Lp2 respectively, it can perform an interleaved operation, and by making the magnetic fluxes generated in the magnetic elements alternate instead of being simultaneous, the magnetic flux summation, that is, it is difficult to saturate.

[0022] Furthermore, since the power conversion device 100 can control the current application to the primary transformers Lp1 and Lp2 respectively, by performing an interleaved operation, the L (reactance) during boosting becomes higher than the L (reactance) in the conventional parallel connection, so that the current ripple can be reduced. Further, the power conversion device 100 can further reduce the ripple of the combined current of the primary transformers Lp1 and Lp2 by the interleaved operation.

[0023] Specifically, the power conversion device 100 sets the on-duty of the switching element Sa2 according to the following formula (1) by the input voltage Vin and the target voltage VB (boosting operation).

Number

[0024] Furthermore, the power conversion device 100 operates the switching elements S3 and S4 with the same duty as the switching elements Sa1 and Sa2. Furthermore, the power conversion device 100 controls the power transmission amount by the phase difference between the switching element Sa1 and the switching element S3.

[0025] Also, the power conversion device 100 causes the switching elements Sb1 and Sb2 to perform an inverted operation with respect to the switching elements Sa1 and Sa2, that is, an interleaved operation. As a result, the current of the input voltage Vin becomes a combination of the currents Ip1 and Ip2, and the ripple is reduced.

[0026] Also, the power conversion device 100 controls the power transmission amount by the phase difference between the switching element Sb1 and the switching element S5.

[0027] According to the embodiment described above, one end of each of the two primary-side transformers Lp1 and Lp2, which are magnetically coupled to circuits B and C on the secondary side, is electrically connected to input / output terminals 1 and 2, while the other ends of the two primary-side transformers Lp1 and Lp2 are electrically connected to different switching elements Sa1, Sb1, and Sb2, respectively. As a result, no induced voltage is generated, and losses can be reduced.

[0028] Furthermore, according to one embodiment, the power converter 100 can control the current applied to the primary transformer Lp1 and the primary transformer Lp2, respectively. By performing interleaving operation, the reactance L (reactance) becomes higher than that of the conventional parallel configuration when boosting the voltage, thus reducing current ripple.

[0029] Furthermore, according to one embodiment, the power converter 100 has switching elements Sb1 and Sb2 performing inversion operation of switching elements Sa1 and Sa2, i.e., interleaving operation. As a result, the current of the input voltage Vin becomes the sum of current Ip1 and current Ip2, reducing ripple.

[0030] Further effects and modifications can be readily derived by those skilled in the art. Broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents.

[0031] Although some embodiments of this application have been described in detail above with reference to the drawings, these are illustrative examples, and the present invention can be implemented in various other forms with modifications and improvements based on the knowledge of those skilled in the art, starting with the embodiments described in the disclosure section of the present invention. [Explanation of symbols]

[0032] 1~6 input / output terminals 100 Power converter A,B,C circuit Capacitors C1~C3, C21~C23, C31~C33 Sa1, Sa2, Sb1, Sb2, S3, S4, S5, S6 switching elements Tr transformer Lp1, Lp2 Primary winding Ls3, Ls4 Secondary Transformer

Claims

1. A power conversion device capable of exchanging power between the primary and secondary sides using a transformer, One end of each of the two primary-side transformers, which are magnetically coupled to the two circuits on the secondary side, is electrically connected to the input / output terminals, while the other ends of the two primary-side transformers are electrically connected to different switching elements. Power converter.

2. A power conversion device according to claim 1, The two primary side transformers mentioned above are The input and output terminals are electrically connected to each other in parallel, Power converter.

3. A power conversion device according to claim 2, The aforementioned different switching elements are controlled to be turned on and off at different timings. Power converter.

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