TWI534449B - Apparutus and method for measuring magnetic saturation point of energy storage device - Google Patents

Description

Magnetic saturation point measuring device for energy storage element and magnetic saturation point measuring method

The present invention relates to a measuring device for an energy storage device and a measuring method thereof, and more particularly to a magnetic saturation point measuring device and a magnetic saturation point measuring method for an energy storage device.

The energy storage component, such as a transformer or an inductor, is usually composed of a winding and a magnetic core, and has the characteristics of energy storage, energy conversion, and electrical isolation, and is an electronic component necessary for forming a power supply circuit.

Under normal operating conditions, the magnetic flux density of the energy storage element increases proportionally with the increase of current; however, when the magnetic flux density in the energy storage element reaches a certain value, even if the applied current gradually increases, the magnetic flux The physical phenomenon in which density remains the same is called magnetic saturation. In short, magnetic saturation means that the magnetic flux density of the energy storage element no longer increases significantly with the increase of the applied current.

When the energy storage component is magnetically saturated, the inductance of its windings is significantly reduced, causing overheating or damage to other components in the core component or power supply circuit.

The present invention provides a magnetic saturation point measuring device for an energy storage element that obtains a magnetic saturation point of an energy storage element by a current slope.

According to the present invention, a magnetic saturation point measuring device for an energy storage element is provided for measuring a magnetic saturation point of an energy storage element. The energy storage element has an operating frequency and is disposed between the first end point and the second end point of the magnetic saturation point measuring device of the energy storage element. The magnetic saturation point measuring device of the energy storage element includes a DC power source, a discharge element, a switching element, a switching period controller, a current slope sensor, and a current slope comparator. The DC power supply includes a positive voltage level terminal and a negative voltage level terminal, and the positive voltage level terminal is connected to the first terminal end. A discharge element is bridged between the first end point and the second end point. The switching element is connected to the discharge element and the negative voltage level terminal. The switching cycle controller is electrically connected to the current slope comparator and the switching component, and the switching cycle controller generates a pulse width modulation signal according to the operating frequency to drive the switching component to repeatedly open and close, and the duty ratio of the pulse width modulation signal Increase with time. The current slope sensor is coupled to the second end point, and the current slope sensor senses the current through the energy storage element at a predetermined frequency, and converts the measured current at two adjacent time points into a current slope. The current slope comparator is electrically coupled to the current slope sensor, the current slope comparator receives the current slope of the current slope sensor output, and compares the current slope, wherein the magnetic saturation point is obtained when the equal current slopes are not equal.

According to the present invention, a magnetic saturation point measuring method is provided for measuring a magnetic saturation point of an energy storage component. The magnetic saturation measuring method comprises the following steps: (a) providing a DC power supply according to an operating voltage and an operating frequency of the energy storage component; a pulse width modulation signal having an operating frequency to the energy storage element, wherein the duty ratio of the pulse width modulation signal is gradually increased with time; (b) sensing the conduction to the energy storage element every predetermined time Current, and converting the measured current into a complex current slope; and (c) comparing the current slope values and obtaining a magnetic saturation point of the energy storage element when the adjacent two current slopes are not equal.

10‧‧‧ Magnetic saturation point measuring device for energy storage components

100‧‧‧DC power supply

110‧‧‧Discharge components

120‧‧‧Switching elements

130‧‧‧Switch cycle controller

140‧‧‧Current Slope Sensor

150‧‧‧current slope comparator

30‧‧‧ Energy storage components

300‧‧‧Primary winding

302‧‧‧Secondary winding

A‧‧‧first endpoint

B‧‧‧second endpoint

P1‧‧‧ low level electrode end

P2‧‧‧ high-level electrode end

Q‧‧‧ turning point

RL‧‧ load

1 is a circuit block diagram of a magnetic saturation point measuring device of an energy storage device of the present invention; and FIG. 2 is a current versus time relationship of the energy storage device.

1 is a circuit block diagram of a magnetic saturation point measuring device for an energy storage device of the present invention. The magnetic saturation point measuring device 10 of the energy storage element shown in Fig. 1 is used to measure the magnetic saturation point of the energy storage element 30. The energy storage component 30 is pre-set with an operating voltage and an operating frequency. The magnetic saturation point measuring device 10 of the energy storage element includes a first end point a and a second end point b that connect the energy storage element 30. In FIG. 1, the energy storage component 30 is exemplified by a transformer, and the primary winding 300 of the transformer is connected to the first terminal a and the second terminal b, and the secondary winding 302 of the transformer can be grounded via the load RL. When the energy storage component 30 is an inductor, the winding of the inductor is bridged between the first terminal a and the second terminal b.

The magnetic saturation point measuring device 10 of the energy storage element includes a DC power source 100, a discharge element 110, a switching element 120, a switching period controller 130, a current slope sensor 140, and a current slope comparator 150. The DC power source 100 is used to provide a voltage for measuring the magnetic saturation point of the energy storage element 30, wherein the DC power source 100 outputs a voltage equal to the peak voltage of the operating voltage preset by the energy storage element 30.

The discharge element 110 is connected across the first end point a and the second end point b to be connected in parallel with the energy storage element 30. The discharge element 110 includes a low level electrode end P1 and a high level electrode end P2. When the electric power applied to the high-position electrode terminal P2 is higher than the electric power applied to the low-position electrode terminal P1, the discharge element 110 exhibits a short-circuit state, and the current can flow from the high-position electrode terminal P2 to The low-level electrode terminal P1 can discharge electrical energy stored on the energy storage element 30. When the electric power applied to the high-position electrode terminal P2 is lower than the electric power applied to the low-position electrode terminal P1, the discharge element 110 assumes an open state, and no current passes through the discharge element 110. The low-level electrode terminal P1 of the discharge element 110 is electrically connected to the high-voltage terminal (+) of the DC power source 100 and the first terminal a, and the high-position electrode terminal P2 of the discharge element 110 is electrically connected to the second terminal b. And a current slope sensor 140. In FIG. 1, the discharge element 110 is implemented by a diode, the cathode of the diode (ie, the low-position electrode end) is electrically connected to the first end point a, and the anode (ie, the high-position electrode end) is electrically connected to Second endpoint b.

The switching element 120 is disposed between the high-level electrode terminal P2 of the discharge element 110 and the negative voltage level terminal (-) of the DC power source 100, and is controlled to be turned on or off by a control signal from the switch cycle controller 130, wherein the switch The control signal sent by the period controller 130 is a pulse width modulation signal. A current slope sensor 140 is provided at the second terminal b for sensing current through the energy storage element 30; wherein the current slope sensor 140 can comprise, for example, a Hall effect current sensor. The current slope comparator 150 is electrically coupled to the current slope sensor 140 and the switching period controller 130.

The voltage value on the energy storage element 30 is the product of the inductance value and the current variation rate, that is, V=L(dI/dt); wherein: V is the voltage value on the energy storage element; L is the inductance of the winding of the energy storage element. Value; and dI/dt is the amount of current variation.

Meanwhile, before the energy storage element 30 reaches the magnetic saturation point, the magnetic flux density of the energy storage element 30 increases proportionally with the increase of the current; that is, as the conduction time of the energy storage element 30 increases, the conduction is turned on. The current of the energy element 30 will increase with a first slope, as shown by the solid line in FIG. After the energy storage element 30 reaches the magnetic saturation point, since the inductance of the energy storage element 30 decreases, the current flowing through the energy storage element 30 increases greatly; in other words, after passing the magnetic saturation point, with the energy storage element 30 As the conduction time increases, the current conducting to the energy storage element 30 will increase with a second slope greater than the first slope, as shown by the dashed line in FIG. Therefore, the turning point Q between the first slope and the second slope is the magnetic saturation point of the energy storage element 30.

When performing the magnetic saturation point measurement of the energy storage element 30, the output voltage of the DC power supply 100 must first be equal to the peak voltage of the preset operating voltage of the energy storage element 30, and the switching period controller 130 must output the same as the energy storage element. a control signal of a preset operating frequency of 30 to drive the switching element 120 to repeatedly perform an opening and closing action; wherein, when the switching element 120 is closed, the DC power source 100 charges the energy storage element 30, the current slope sensor 140 can The current that conducts through the energy storage element 30 is measured. When the switching element 120 is turned on, the energy storage element 30 can be discharged through the discharge element 110. In addition, the switching period controller 130 gradually increases the duty cycle of the output pulse width modulation signal to increase the conduction time of the energy storage element 30, so that the current conducted to the energy storage element 30 can be correspondingly increased.

Then, the current flowing through the energy storage element 30 is detected by the current slope sensor 140 at predetermined time intervals, and the current that is conducted to the energy storage element 30 is obtained at at least three different time points; and then, the operation is performed between two adjacent time points. The current slope (ie, the amount of current change) and the calculated at least two current slopes are passed to the current slope comparator 150. Here you must It should be noted that since the frequency of the pulse width modulation signal output by the switching period controller 130 is the same as the preset operating frequency of the energy storage element 30, only the adjustment of the duty ratio is different, and therefore, the current slope is appropriately adjusted. The detector 140 senses a predetermined time interval of the current flowing through the energy storage element 30, and can measure currents corresponding to different duty cycles.

The current slope comparator 150 compares the at least two current slopes output by the current slope sensor 140 to obtain the magnetic saturation point of the energy storage element 30. More specifically, the current slope comparator 150 determines whether the energy storage element 30 is saturated by determining whether the at least two current slopes are equal; wherein if the two current slopes are equal, determining that the energy storage element 30 is not magnetic The saturation point, and if the two current slopes are not equal, it is determined that the energy storage element 30 reaches the magnetic saturation point.

If expressed in a mathematical expression, when the energy storage element 30 does not reach the magnetic saturation point, the following condition 1 is satisfied, and when the energy storage element 30 reaches the magnetic saturation point, the following condition 2 is satisfied:

; Wherein: I _n-1 at time point t _n-1, the current 30 is turned on in the energy storage element; when I _n at time point t _n, conducting a current energy storage element 30, wherein the time point t _n a point in time t _n-1 interval of the predetermined time; I _{n + 1} at time point t _{n + 1,} is turned to a current storage element 30, wherein the time point t _{n + 1} and the time point t _n intervals the predetermined time.

If the current slope comparator 150 determines that the energy storage component 30 is not saturated, the notification signal is output to the switching cycle controller 130 to drive the switching cycle controller 130 to increase the duty ratio of the output pulse width modulation signal to improve the switching component 120. The on time is until the energy storage element 30 reaches saturation.

In summary, the method of measuring the magnetic saturation point of the energy storage element 30 includes the following steps.

First, the preset operating voltage and operating frequency of the energy storage component 30 are obtained, and the DC power source 100 and the pulse width modulation signal having the operating frequency are supplied to the energy storage component 30 according to the operating voltage and the operating frequency. The voltage output by the DC power source 100 is the same as the peak value of the operating voltage preset by the energy storage element 30, and the duty ratio of the pulse width modulation signal gradually increases with time.

Next, the current that conducts through the energy storage element 30 is sensed every predetermined time, and the measured complex current is converted to a complex current slope. The predetermined time for sensing the current flowing through the energy storage element 30 is the same as the single cycle time of the preset operating frequency of the energy storage element 30, and each current slope is calculated by current between two adjacent time points.

Finally, compare the current slope values. When the adjacent two current slopes are not equal, the magnetic saturation point of the energy storage element is obtained; if the adjacent two current slopes are not equal, the duty ratio of the pulse width modulation signal is continuously increased.

While the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and the invention may be modified and modified in various ways without departing from the spirit and scope of the invention. The scope is subject to the definition of the scope of the patent application.

10‧‧‧ Magnetic saturation point measuring device for energy storage components

100‧‧‧DC power supply

110‧‧‧Discharge components

120‧‧‧Switching elements

130‧‧‧Switch cycle controller

140‧‧‧Current Slope Sensor

150‧‧‧current slope comparator

30‧‧‧ Energy storage components

300‧‧‧Primary winding

302‧‧‧Secondary winding

A‧‧‧first endpoint

B‧‧‧second endpoint

P1‧‧‧ low level electrode end

P2‧‧‧ high-level electrode end

RL‧‧ load

Claims (10)

A magnetic saturation point measuring device for measuring an energy storage component for measuring a magnetic saturation point of an energy storage component, the energy storage component having an operating frequency and disposed at a first end of the magnetic saturation point measuring device of the energy storage component Between the point and a second end point, the magnetic saturation point measuring device of the energy storage component comprises: a DC power source, comprising a positive voltage level terminal and a negative voltage level terminal, wherein the positive voltage level terminal is connected to the first An end point; a discharge element connected between the first end point and the second end point; a switching element connecting the discharge element and the negative voltage level terminal; a switching cycle controller electrically connected to the a switching element, wherein the switching period controller generates a pulse width modulation signal according to the operating frequency to drive the switching element to repeatedly open and close, and the duty ratio of the pulse width modulation signal increases with time a current slope sensor coupled to the second terminal, the current slope sensor sensing current through the energy storage element at the predetermined frequency, and converting the measured current at two adjacent time points Is the current slope; And a current slope comparator electrically coupled to the current slope sensor, the current slope comparator receiving a complex current slope of the current slope sensor output, and comparing the current slopes, wherein the current slopes are not equal At this time, the magnetic saturation point is obtained. The magnetic saturation point measuring device of the energy storage device of claim 1, wherein the current slope comparator drives the switching cycle controller to continuously increase the pulse width modulation signal when the current slopes are equal Empty ratio. The magnetic saturation point measuring device of the energy storage device according to Item 1, wherein the current slope sensor senses at least three currents passing through the energy storage element, and turns the measured three currents The current slope is compared to the two current slopes, and the magnetic saturation points are obtained when the current slopes are not equal. The magnetic saturation point measuring device of the energy storage device according to Item 1, wherein the DC power output voltage is the same as the peak voltage of the operating voltage preset by the energy storage device. The magnetic saturation point measuring device of the energy storage device of claim 1, wherein the discharge element is a diode, and the current slope sensor comprises a Hall effect current sensor. A magnetic saturation point measuring method is suitable for measuring a magnetic saturation point of an energy storage component, the magnetic saturation measuring method comprising: (a) providing a DC power source according to an operating voltage of the energy storage component and an operating frequency, and having a pulse width modulation signal of the operating frequency is applied to the energy storage element, wherein a duty ratio of the pulse width modulation signal is gradually increased with time; (b) sensing is turned on at the storage every predetermined time The current of the component, and converting the measured complex current into a complex current slope; and (c) comparing the current slope values, and obtaining a magnetic saturation point of the energy storage element when the adjacent two current slopes are not equal. The magnetic saturation point measuring method according to Item 6, wherein each of the current slopes is calculated by current between adjacent two time points. The magnetic saturation point measuring method according to Item 6 of the claim further includes the following steps: (d) continuously increasing the duty ratio of the pulse width modulation signal when the adjacent two current slopes are not equal. The magnetic saturation point measuring method according to Item 6, wherein the DC power output voltage is the same as the peak voltage of the operating voltage preset by the energy storage element. The magnetic saturation point measuring method of claim 6, wherein the predetermined time is the same as a single cycle time of the operating frequency.