JP2006262654A - Power conversion system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To construct a power conversion system which includes follow-up features where high-speed response is attained with respect to rapid load fluctuations for a short time, and stable controllability to a wide-range load fluctuation state. <P>SOLUTION: Control circuits 4, 5 of a non-insulated DC/DC electric power converter includes conventional control circuits 41, 51 for controlling the voltage of the power converter by PWM, high-speed start circuits 42, 52, and control selecting circuits 43, 53. The high-speed starting circuits have functions to observe an inductor current, and to indicate an ON signal continuously, until the inductor current becomes a stated inductor current which is a current value, flowing through an inductor 22 obtained when a load 3 is rapidly changed and the load 3 is finally stabilized. The control selecting circuits detect the output state of the power converter and decide whether control by the conventional control circuits is adopted or the control by the high-speed starting circuits is adopted, then outputs a selected control output to the power converter. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to high-speed response control of a power converter, and more specifically to control of a power converter (DC / DC power converter) that accompanies sudden load fluctuations.

  In the power converter (DC / DC converter) described in Patent Document 1, power conversion is performed so that the target voltage is obtained by adjusting the pulse width by general feedback control.

JP 2002-218667 A (FIG. 12)

  In the conventional technology, when a sudden load fluctuation occurs, the control circuit operates with the maximum duty set and tries to transmit power. When the conversion power is changed over a wide range, the control becomes like hunting, and there is a possibility of falling into an unstable state. Also, in order to stabilize the conversion power range over a wide range, if the maximum duty of the system is set based on the operating duty at the maximum power, if the load fluctuates suddenly, it will not follow as expected, and the output voltage There was a case where a decrease in the amount occurred. Therefore, in the latter case, it is necessary to provide a sufficient capacitor at the output end to guarantee energy until the power converter can follow at the maximum load.

  The present invention has been made in view of such problems, and an object of the present invention is to construct a power conversion system having both followability and stability.

  The subject of the present invention is a power conversion system comprising a non-isolated DC / DC power converter having an inductor and a control circuit thereof, wherein the control circuit is a PWM and the control circuit of the non-isolated DC / DC power converter. The first control circuit for controlling the output voltage and the inductor current flowing through the inductor are observed, and the inductor current is finally changed due to a sudden change in the load of the non-insulated DC / DC power converter. A second control circuit having a function of continuously instructing an ON signal until a specified inductor current which is a current value flowing through the inductor when the load is stabilized; and the non-insulated DC / DC power The state of the output of the converter is detected to determine whether the control by the first control circuit or the control by the second control circuit is taken, and the selected control output is sent to the non-insulated D / Wherein the DC and a control selection circuit which outputs to the power converter.

  Hereinafter, various embodiments of the subject of the present invention will be described in detail along with the effects and advantages thereof with reference to the accompanying drawings.

  According to the subject matter of the present invention, by selecting between basic PWM control and control by a high-speed start-up circuit, (1) follow-up capability capable of responding to rapid load fluctuations in a short period of time and (2) It is possible to construct a power conversion system having both stable controllability with respect to a wide range of load fluctuations.

(Features of the present invention)
In order to solve the above problems, the present invention provides (1) a first control circuit that performs basic control, and (2) second control that rapidly charges an inductor current when a sudden load fluctuation occurs. Constructs a power conversion system that has both follow-up and stability by switching control appropriately by a control selection circuit that has two control circuits and selects the control output of the first and second control circuits. To do.

  Specifically, the first control circuit that performs basic PWM control is designed so that it is rather stable, and is set so that it does not have to follow such a high speed for sudden load fluctuations. In order to cope with a sudden load fluctuation, the second second control circuit is kept ON for a period necessary for charging the inductor in the power converter, and the inductor current is increased rapidly. Have a function to control. Furthermore, a circuit that appropriately selects these control outputs according to the degree of load variation, the first control circuit is selected for moderate load variation, and it follows gently by normal control, and sudden load variation occurs. If there is, the second control circuit is selected and the inductor current is charged rapidly to cope with the load fluctuation at high speed.

  By such response control, it is possible to construct a power conversion system having both followability to a sudden load change and stability in a wide range of power settings. However, since power conversion is not performed during the period when the inductor is charged, it is necessary to guarantee the power by the capacitor. However, the capacity of the capacitor necessary for this period is compared with the conventional power conversion system. It is possible to set to 1/2 to 2/3.

  The “rapid load fluctuation” referred to in the present application refers to a state in which the power converter side requests an output that is increased more than when the load is in a stable operation. For example, the load operates stably at a load output of 1 W. This is a case where the load side asks to output 2 W to 10 W of power to the power converter. In other words, it can be said that this is a case where the load requires an increase in output power of, for example, about five times or more than that in the previous stage.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration example of the power conversion system according to the present embodiment, together with its control flow. In FIG. 1, reference numeral 1 is a direct current power source such as a battery, and block 2 is a main circuit of a power conversion circuit (also referred to as a power converter) such as a non-insulated bidirectional DC / DC converter. The load 3 is connected between both terminals 28 and 29 of the power conversion circuit 2. The load 3 further includes a device that performs power conversion.

  One control circuit 4 is a step-up control circuit for performing step-up control of the power converter 2 (that is, converting the electric power of the DC power source 1 to be applied to the load 3). The other control circuit 5 is a step-down control circuit for performing step-down control of the power converter 2 (that is, performing an operation of regenerating energy from the load 3 to the DC power source 1 by power conversion). Further, the selection circuit 6 provided in each of the control circuits 4 and 5 boosts the power conversion circuit 2 by a boost command with an external control signal, or causes the power conversion circuit 2 by a buck command with an external control signal. Step down. However, the step-up command and the step-down command are not input to the selection circuit 6 at the same time. Block 7 is a control flow of this method.

  The power conversion circuit 2 is an example of a DC / DC converter that can perform power conversion in both the step-up and step-down directions. A capacitor 21 is connected inside the power conversion circuit 2 in parallel with the DC power supply 1. One end of the inductor 22 is connected to the positive terminal of the capacitor 21, and the other end of the inductor 22 is connected to the input of the boost switch 23 and the anode of the rectifying element 24. In addition, the other end of the inductor 22 is also connected to the output of the step-down switch 25 and the cathode of the rectifying element 26. The output of the boosting switch 23 is connected to the negative terminal of the capacitor 21 together with the anode of the rectifying element 26, and the negative terminal of the capacitor 27 is connected to the negative terminal of the capacitor 21. The negative terminal 27 has an output COM28. On the other hand, the input of the step-down switch 25 and the cathode of the rectifying element 24 are connected to the positive terminal of the capacitor 27, and the positive terminal of the capacitor 27 forms the output Vout 29. The output 3 of the power conversion circuit 2 is connected to the load 3 as a positive electrode, and the output COM 28 of the circuit 2 is connected as a negative electrode.

  The output current sensor 81 in the power conversion circuit 2 is current detection means for observing the load current Iout, and the output voltage sensor 82 is output voltage detection means. Further, the inductor current sensor 83 in the circuit 2 serves as means for observing the inductor current Iin and also serves as output current detection means at the time of step-down. The voltage sensor 84 is a voltage detection means on the step-down side.

  The step-up control circuit 4 and the step-down control circuit 5 perform step-up control and step-down control based on the information observed by the detection means 81 to 84 described above.

  Reference numeral 9 denotes a load controller for driving or controlling the load such as an inverter. The load controller 9 outputs a control signal 91 for the load 3. Further, the load controller 9 transmits the driving state of the load 3 as a load state signal 92 to the step-up control circuit 4 or the step-down control circuit 5 or to both the control circuits 4 and 5.

  The step-up control circuit 4 includes a conventional control circuit (first control circuit) 41, a fast startup circuit (inductor current control circuit; second control circuit) 42, and a control selection circuit 43. Among these, the conventional control circuit 41 is equipped with a control circuit for a generally used PWM-controlled DC / DC converter. That is, the conventional control circuit 41 is a control circuit for controlling the output voltage of the power converter by PWM. On the other hand, the fast start-up circuit 42 observes the current of the inductor 22 based on the output of the inductor current sensor 83 and continuously sends an ON signal to the boosting switch 23 until the current flowing through the inductor 22 becomes the specified inductor current. It is equipped with a circuit that has a function to instruct. That is, in the fast start-up circuit 42, the current flowing through the inductor 22 with respect to a sudden load change becomes the “regular inductor current value” that is the inductor current when the load 3 fluctuates and the load fluctuation finally stabilizes. Until it becomes, it has the control function which charges the inductor 22 continuously (continuously increases the inductor current). Further, the control selection circuit 43 detects the output state of the power converter 2 based on any one of the output of the output voltage sensor 82, the output of the output current sensor 81, and the load state signal 92, and the conventional control circuit It is determined whether the control of 41 or the fast start-up circuit 42 is to be controlled, and the control circuit output on the selected side is output to the power converter 2. When the boost command is input to the selection circuit 6, the boost control circuit 4 controls the boost operation of the power converter 2 by the selection of the control circuits 41 and 42.

  The step-down control circuit 5 includes a conventional control circuit (first control circuit) 51, a fast startup circuit (inductor current control circuit; second control circuit) 52, and a control selection circuit 53. Among these components, the conventional control circuit 51, like the conventional control circuit 41, is equipped with a generally used PWM-controlled DC / DC converter control circuit, and also has a fast startup circuit. 52 has a function of observing the inductor current and continuously instructing the step-down switch 25 to turn on the signal until the current flowing through the inductor 22 reaches the specified inductor current, as in the above-described fast startup circuit 42. In addition, the control selection circuit 53 detects the output state of the power converter 2 and controls the conventional control circuit 51 in the same manner as the control selection circuit 43 described above, or It is determined whether to control the fast start circuit 52. By the selection of the control circuits 51 and 52 described above, the step-down control circuit 5 controls the step-down operation of the power converter 2.

  Next, the control of this method will be described based on the control flow 7 of FIG. The control flow 7 is common to the control flow of the step-up control circuit 4 and the control flow of the step-down control circuit 5.

  After DC / DC start-up (step 71), the control selection circuit 43 or 53 normally selects the conventional control circuit 41 or 51, and is always in steady state control (optimum duty control; PWM control) by the conventional control (41 or 51). ) To operate the power converter 2 (step 72). In step 73, when the control selection circuit 43 or 53 detects the fluctuation of the load 3 (load increase), the circuit 43 or 53 sets the high-speed start completion condition (step 74) and at the same time whether or not to perform high-speed start-up. Is determined (step 75). When the high-speed start-up is unnecessary (NO determination), the control selection circuit 43 or 53 selects the conventional control circuit 41 or 51 that performs the PWM control, and on the other hand, a sudden load fluctuation that requires the high-speed start-up has occurred. In the case (YES determination), the fast startup circuit 42 or 52 is selected. Note that the setting of the fast start completion condition in step 74 may be performed after the fast start determination “Y” is confirmed in step 75. When the fast start determination “Y” is confirmed in step 75, the control selection circuit 43 or 53 selects the fast start circuit 42 or 52 to operate the fast start control until the fast start completion condition set in step 74 is satisfied. When the load 3 becomes stable and the completion determination “Y” is confirmed in step 77, the control selection circuit 43 or 53 continues. Selects the conventional control circuit 41 or 51 again, and the conventional PWM control is restored (step 72).

  By such selective control between conventional control and high-speed start-up, both (1) followability capable of more precisely responding to sudden load state fluctuations and (2) stability over a wide range of power settings. The equipped power conversion system can be constructed.

  FIG. 2 shows a timing chart according to the present system when the power converter 2 includes only the boost control circuit 4 in comparison with the conventional example. As shown in the figure, by selecting the fast start-up circuit 42 at the time of a sudden load state change, the control signal (ON state) continuously during the period when the current of the inductor 22 continues to rise from the 0 value to the specified value ( The pulse width is larger than the pulse width of the signal of the conventional control), but is continuously applied to the boosting switch 23 via the control selection circuit 43. Then, after the current of the inductor 22 reaches the specified value, the conventional control (PWM control) is restored.

(Embodiment 2)
The present embodiment relates to a specific example of the fast start-up circuits 42 and 52 in the first embodiment, and FIG. 3 is a block diagram showing the fast start-up circuit according to the present embodiment. In description of this Embodiment, the component of FIG. 1 and its reference symbol are used as needed.

  This fast start circuit compares the fixed value A preset in the current value setting circuit 421 with the signal B from the inductor current sensor 83 by the comparison circuit 422, and the first and second waveform shaping according to the comparison result. A pulse is output from the circuits 423 and 424. That is, when the comparison result in the comparison circuit 422 is A> B and the comparison output C is “1” level, the first waveform shaping circuit (waveform shaping circuit 1) 423 removes the noise component, and then the fast start signal ( Level “1”) is extracted. At the same time, the second waveform shaping circuit (waveform shaping circuit 2) 424 removes a noise component from the output of the comparison circuit 422 and then falls the output of the comparison circuit 422 (1 → 0 transition: A <B, C = “0”) is generated and a completion pulse instructing completion of high-speed startup is generated and output. These signals are given to the control selection circuit 43 as control signals from the fast start circuit.

  The operation example 1 illustrated in the block 425 of FIG. 3 schematically shows a state in which the inductor current increases when the inductor current hardly flows at a light load and a high load state is reached. The fast start pulse always outputs level “1” when the inductor current B is less than the set current value A, and waits for the control selection circuit 43 to select its own signal. After that, when the load becomes high and the inductor current needs to be increased, the fast start pulse is selected by the control selection circuit 43, and the current flowing through the inductor 22 continuously increases like the inductor current shown in the block 425. To do. After that, when the inductor current B becomes equal to or higher than the set current value A, the high speed start circuit outputs a high speed start pulse of level “0”, stops the output of the pulse, and further completes as a fast start completion signal. Is output, and the control selection circuit 43 is requested to complete the high-speed start-up and take over to the conventional control. The waveform of the inductor current shown in the block 425 is a waveform that has been switched to the conventional control by the generation of the completion pulse after the fast startup.

  On the other hand, in the operation example 2 illustrated in the block 426 of FIG. 3, the inductor current at the output required as the output of the DC / DC converter is set to an eye that is equal to or lower than the set current value. The waveform in the case of the case is schematically shown. In this operation example, the fast start pulse is always output, and the waveform is likely to malfunction due to the fast start pulse. However, the control selection circuit 43 selects normal conventional control by the completion pulse after the fast start pulse is output. As a result, the fast start pulse is not selected, and the control is performed so as not to cause a malfunction.

  If the control according to the present embodiment described above is performed, the DC / DC converter can quickly charge the inductor current during a sudden load change, and can respond more precisely, and stability over a wide range of power settings. Thus, it is possible to construct a power conversion system having both of the above.

(Embodiment 3)
The present embodiment proposes a multi-stage or stepless current value setting circuit in place of the current value setting circuit 421 in the second embodiment.

  FIG. 4 is a block diagram showing an example of a current value setting circuit for a fast start circuit according to the present embodiment. The current value setting circuit 427 shown in FIG. 4 is set to include a plurality of current value setting circuits 421 shown in FIG. 3. By providing the current setting value group 4211, currents corresponding to prescribed current values that are not the same are provided. Multiple values are set. Then, any one of the outputs A1, A2, A3,... Of each current value setting circuit (4211.1, 4211.2, 4211.3,...) Is sent by the current setting selection circuit 4212. To be elected. For selection in the current setting selection circuit 4212, the load determination signal 4213 determines the load state from the load state signal 92 of the load controller 9, and a plurality of outputs A1, A2, A3,.・ ・ Determine which current setting value is to be selected as the “specified inductor current value”. Since the control selection circuit 43 has the same function as the selection determination circuit 4213, the control selection circuit 43 may be modified to have the selection determination circuit 4213.

  FIG. 5 is a diagram showing a circuit example in the case where the prescribed inductor current value is set in a stepless manner. The current value setting circuit 428 performs arithmetic processing on a load state signal (analog signal before load state determination or digital data signal before load state determination) 92 for determining the state of the load 3 to obtain a specified current value of the inductor current. Set to stepless.

  According to this embodiment, in a DC / DC converter, an inductor current corresponding to a load change instruction is rapidly charged in a rapid load change, and a follow-up property capable of responding more precisely and stable in a wide range of power settings. Therefore, it is possible to construct a power conversion system having both characteristics.

(Embodiment 4)
The present embodiment embodies the configuration of the control selection circuit 43 shown in FIG. 1 of the first embodiment, and is characterized by the load state signal 92, the output of the output voltage sensor 82, and the output current sensor. When an abrupt load change is detected reliably and optimally based on at least one signal among the 81 outputs, the output pulse of the fast start-up circuit (second control circuit) 42 is selected, and then the load change becomes stable At this stage, the control is switched to the PWM control by the conventional control circuit (first control circuit) 41. Hereinafter, based on the drawings, the control selection circuit 43 according to the present embodiment will be described. Regarding other components, the description in any of FIGS. 1 and 3 to 5 is incorporated.

  FIG. 6 is a block diagram schematically showing the configuration of the control selection circuit 43 of the boost control circuit 4 according to the present embodiment. In the figure, a voltage change detection circuit 431 outputs a fast start command pulse B due to an increase in the load 3 from voltage information from the output voltage sensor 82 and a set reference. On the other hand, the current change detection circuit 432 outputs a fast start command pulse C due to an increase in the load 3 from the current information from the output current sensor 81 and the set reference. On the other hand, the selection logic 433 is reliable based on each logical expression from the fast start command pulses B and C of both the circuits 431 and 432 and the load state signal 92 (logic signal that determines the increase in the load 3). As information, a signal for high-speed startup is generated. The latch control circuit 434 holds the high-speed start by the latch circuit when the high-speed start selection signal from the selection logic 433 is input, and receives the completion pulse from the high-speed start circuit 42 or forcibly ends the circuit 434. The high-speed startup hold is canceled by a signal from the timer. Here, the forced termination timer is a protection circuit for a case where the completion pulse from the fast start circuit 42 is not input due to some trouble. Further, the selection circuit 435 outputs the control signal of the conventional control circuit 41 when the output from the latch control circuit 434 is “0”, while the high speed when the output from the latch control circuit 434 is “1”. A logic circuit or the like is configured so as to output a signal from the activation circuit 42.

  The circuits 431 and 432 and the load state signal 92 are not necessarily required for the selection logic 433. Among these 431, 432 and 92, necessary circuits are installed or the signal 92 is received according to system requirements. By adopting the optimum logical expression in the selection logic 433, an optimum system can be constructed. That is, at least one element is required among the circuits 431 and 432 and the load state signal 92 (corresponding to the case where any one of the logical expressions (11) to (13) of the selection logic 433 is employed).

  According to the present embodiment, it is possible to construct a power conversion system capable of accurately detecting sudden load fluctuations and switching control.

(Embodiment 5)
The present embodiment corresponds to an example in which the configuration of the control selection circuit 43 in FIG. 6 of the fourth embodiment is modified, and the feature thereof is the current setting circuit 427 or 428 described in the third embodiment. Assuming a power conversion system including a high-speed start-up circuit having the control circuit 43, the control selection circuit 43 outputs the output signal 92 of the load controller 9 of the load 3, the output signal and power of the output voltage sensor 82 in the power converter 2. A load state signal is internally generated based on at least one of the output signals of the output current sensor 81 in the converter 2, and the fast start circuit 42 uses the load state signal output from the control selection circuit 43. Based on this, the specified inductor current value is set. Hereinafter, the configuration and operation of the control selection circuit 43 according to the present embodiment will be described based on the drawings.

  FIG. 7 is a block diagram showing a configuration of the control selection circuit 43 in the boost control circuit 4 according to the present embodiment. In the figure, a voltage change detection circuit 436 outputs a load state signal (analog or digital value) and a fast start command pulse due to an increase in load from a set reference from the voltage information from the output voltage sensor 82. From the current information from the output current sensor 81, the current change detection circuit 437 outputs a load state signal (analog or digital value) and a fast start command pulse due to an increase in load from a set reference. The conversion circuit 438 converts the command value 92 from the load controller 9 into an analog value when processing with analog data. The load state output from which the analog value or the digital value is output from these circuits 436, 437, and 438 is held as a load state signal by the holding circuit 439, and the holding circuit 439 converts the held load state signal into FIG. Or it inputs into the fast starting circuit 42 which has the electric current value setting circuit of FIG. The selection logic 433 generates a signal for high-speed activation as reliable information from the logic signals from the circuits 436 and 437 and the signal 92 based on each logical expression. This is the same as the selection logic 433 shown in FIG. The latch control circuit 434 holds the high-speed start by the latch circuit when the high-speed start selection signal from the selection logic 433 is input, and inputs a completion pulse from the high-speed start circuit 42 or a signal from the forced end timer in the latch control circuit 434. Then, release the hold of fast start. The forced termination timer is a protection circuit for a case where the completion pulse from the fast start circuit 42 is not input due to some trouble. The selection circuit 435 outputs the control signal of the conventional control circuit 41 when the output from the latch control circuit 434 is “0”, and the fast start circuit when the output from the latch control circuit 434 is “1”. It is composed of a logic circuit or the like so as to output 42 control signals. It should be noted that not all of the circuits 436, 437, and 438 described above are essential for the generation and output of the load state signal, but at least one of these circuits 436 to 438 is selected according to system requirements. What is necessary is just to set a circuit. Similarly, a necessary circuit or signal 92 is installed from among the circuits 436, 437, and signal 92 according to system requirements, and an optimum logical expression is adopted by the selection logic 433 to construct an optimum system. I can do it.

  According to the present embodiment, it is possible to construct a power conversion system that can accurately detect sudden load fluctuations and set appropriate control and control parameters according to the degree of load fluctuations.

(Embodiment 6)
The feature of the present embodiment is that the high-speed start-up circuit 42 selects and controls only the completion pulse for completing the high-speed start-up instructing the ON signal continuously when the inductor current corresponds to the specified inductor current value. The control selection circuit 43 outputs a control signal for self-starting itself during a period when a sudden load change is detected and the completion pulse from the fast starting circuit 42 is not input. The output is to the isolated DC / DC power converter, and the control is switched from the fast start to the control by the conventional control circuit 41 in response to the reception of the completion pulse from the fast start circuit 42. The characteristic points of the configuration of the control selection circuit 43 will be described below based on the drawings.

  FIG. 8 is a block diagram illustrating a partial configuration of the fast start-up circuit 42 and the control selection circuit 43 according to the present embodiment. The control selection circuit 43 has a selection logic 433 as shown in FIG. 6 or FIG. In order to realize high-speed drive control that requires rapid charging of the inductor 22, here, the output of the selection logic 433 is input to the set terminal S of the latch of the latch control circuit 434, and the selection circuit 430 performs latch control. It is configured as an OR connection between the latch output of the circuit 434 and the conventional control pulse. On the other hand, the fast start-up circuit 42 uses only the circuit that generates and outputs the completion pulse by removing the noise component and the like by the waveform shaping circuit 429 from the output of the comparison circuit 422. With such a configuration, the configuration of the fast startup circuit 42 and the selection circuit 430 can be simplified.

  According to the present embodiment, by giving control priority to the high-speed startup circuit, it is possible to easily realize a selection function between high-speed startup and normal control. However, unlike the normal configuration of the first embodiment, the switching determination is not performed.

  Each of the second to sixth embodiments describes only the step-up control of the step-up control circuit 4, but of course, the step-down control of the step-down control circuit 5 is also described in each of the second to sixth embodiments. The same configuration can be applied.

(Embodiment 7)
The feature of the present embodiment is that the load controller 9 itself knows the state of the load 3, and this point is used to perform high-speed start-up control before causing a load fluctuation.

  FIG. 9 is a block diagram illustrating a configuration example of the control selection circuit 43 according to the present embodiment. When the load controller 9 that controls the load 3 exists, the operation information of the load controller 9 is input to the control selection circuit 43 in advance. When the load controller 9 enters the rapid increase sequence of the load 3, the load controller 9 outputs a load fluctuation logic output 92, and at the same time outputs a status signal 92 of the load 3 as digital data. The control selection circuit 43 includes a latch control circuit 434, a selection circuit 435, and a holding circuit 439. Accordingly, the fast start-up circuit 42 is started by the signal of the load fluctuation logic output 92, and the current setting circuit 421 can be set in a single (FIG. 3) or multiple stages (FIGS. 4 and 5). Furthermore, the circuit can be simplified by combining the configuration described in Embodiment 6 with the present embodiment instead of the selection circuit 435, that is, the selection circuit 430.

  According to the present embodiment, since the high-speed start-up is started before the load is changed, the delay until the determination after the load change → rapid charge → DC / DC drive can be further improved. In addition, it is possible to construct a power conversion system that can handle higher speeds.

(Appendix)
While the embodiments of the present invention have been disclosed and described in detail above, the above description exemplifies aspects to which the present invention can be applied, and the present invention is not limited thereto. In other words, various modifications and variations to the described aspects can be considered without departing from the scope of the present invention.

  The power conversion system according to the present invention is used for, for example, voltage control of a previous stage input to an inverter in an electric vehicle or hybrid vehicle having a power conversion function, an electric device controlled by VVVF, or the like.

It is a figure which shows the structure of the power conversion system which concerns on Embodiment 1 of this invention. It is a figure which shows the example of a system configuration at the time of applying this invention to a booster circuit, and its timing chart. It is a figure which shows the structural example of a high-speed starting circuit, and its operation example. It is a figure which shows the structural example of the electric current value setting circuit (multistage) in a high-speed starting circuit. It is a figure which shows the structural example (arithmetic processing) of the electric current value setting circuit (stepless) in a high-speed starting circuit. It is a figure which shows the structural example (when the current setting in a high-speed starting circuit is single) of a control selection circuit. It is a figure which shows the structural example (when the electric current setting in a high-speed starting circuit is multistep or a non-step) of a control selection circuit. It is a figure which shows the example of a structure of the selection circuit in a control selection circuit when a circuit is simplified, and a quick start-up circuit. It is a figure which shows the structural example of the control selection circuit at the time of the control switching structure by a load controller.

Explanation of symbols

1 DC power supply, 2 non-isolated bidirectional DC / DC power converter, 3 load, 4 step-up control circuit, 41 conventional control circuit, 42 fast start-up circuit, 43 control selection circuit, 5 step-down control circuit, 51 conventional control circuit, 52 Fast start-up circuit, 53 Control selection circuit.

Claims (7)

A power conversion system comprising a non-insulated DC / DC power converter having an inductor and a control circuit thereof,
The control circuit includes:
A first control circuit for controlling an output voltage of the non-insulated DC / DC power converter by PWM;
By observing the inductor current flowing through the inductor, the inductor current flows through the inductor when the load of the non-isolated DC / DC power converter suddenly fluctuates and finally becomes stable. A second control circuit having a function of continuously instructing an ON signal until a specified inductor current as a current value is reached;
The output of the non-insulated DC / DC power converter is detected to determine whether the control by the first control circuit or the control by the second control circuit is taken, and the control output of the selected one is selected And a control selection circuit that outputs to the non-insulated DC / DC power converter,
Power conversion system. The power conversion system according to claim 1,
The second control circuit includes:
The predetermined inductor current value set in advance and the inductor current are compared, and when the relationship of the specified inductor current value> the inductor current is satisfied, the fast start pulse that instructs the ON signal continuously While outputting to the control selection circuit, when the inductor current corresponds to the specified inductor current value, a completion pulse for completing the high-speed startup is output to the control selection circuit,
Power conversion system. The power conversion system according to claim 2,
The second control circuit has a function capable of setting the specified inductor current value not in a single unit but in multiple steps or in a stepless manner.
Power conversion system. The power conversion system according to any one of claims 1 to 3,
The control selection circuit selects the second control circuit when a sudden load change is detected, and then switches to the control by the first control circuit when the load change becomes stable.
Power conversion system. The power conversion system according to claim 3,
The control selection circuit includes an output signal of a load controller of the load, an output signal of an output voltage sensor in the non-isolated DC / DC power converter, and an output current sensor in the non-isolated DC / DC power converter. Generating a load condition signal based on at least one of the output signals;
The second control circuit sets the prescribed inductor current value based on the load state signal output from the control selection circuit,
Power conversion system. The power conversion system according to claim 4, wherein
The second control circuit outputs, to the control selection circuit, a completion pulse for completing a high-speed start instructing the ON signal continuously when the inductor current corresponds to the specified inductor current value,
The control selection circuit outputs a control signal for performing the fast startup by itself when the sudden load fluctuation is detected and the completion pulse is not input. And switching from the high-speed startup to the control by the first control circuit in response to reception of the completion pulse from the second control circuit,
Power conversion system. The power conversion system according to claim 1,
When the load fluctuation can be detected in advance, the control circuit operates the second control circuit that performs high-speed activation that continuously instructs the ON signal in advance in accordance with the timing of the load fluctuation. It has a function,
Power conversion system.

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