CN100403616C

CN100403616C - Phase defect testing method for three phase power supply

Info

Publication number: CN100403616C
Application number: CNB2005100541709A
Authority: CN
Inventors: 谢庭钟; 廖世杰
Original assignee: Delta Optoelectronics Inc
Current assignee: Delta Electronics Inc; Delta Optoelectronics Inc
Priority date: 2005-03-04
Filing date: 2005-03-04
Publication date: 2008-07-16
Anticipated expiration: 2025-03-04
Also published as: CN1828319A

Abstract

The present invention provides a three-phase power supply phase defect detecting method which comprises the following steps that firstly, a detection condition of a phase defect state is established, and the voltage variation of a DC bus is detected in a sampling period so as to obtain the voltage value and the frequency value of the ripple voltage on the DC bus; secondly, the voltage value and the frequency value are compared according to the detecting condition of the phase defect state; when the voltage value and the frequency value accord with the detecting condition of the phase defect sate, the phase defect state of the three-phase power supply is determined. The present invention judges the phase defect condition of the three-phase power supply according to the characteristic of the change of the frequency value and the amplitude of the ripple voltage on the DC bus when the phase defect condition of the inputted three-phase power supply occurs in a power converter, the matching mode of the sensor in a power converter and the software calculation, and the variation of the sample and the continuous ripple voltage detection. Then, when the detected ripple voltage accords with the phase defect condition, the present invention can determine the phase defect state of the three-phase power supply.

Description

Three phase mains is owed the detection method of phase

Technical field

The present invention is about a kind of power state detection method, particularly a kind ofly judges that with software mode three phase mains owes the detection method of phase.

Background technology

Along with the application of power electronics is universal day by day, the use of electric power converter such as UPS and frequency converter is very extensive, please refer to Fig. 1, system block diagrams for general frequency converter, three phase mains is direct voltage by rectifier 10 with ac voltage rectifier, and filter circuit 20 becomes more galvanic current after with the pulsating dc voltage filtering after the rectification and presses (dc bus), uses to offer frequency converter 30; Then, the required power supply of 30 generation motors of frequency converter, 50 runnings, control circuit is then in order to control the circuit operation of rectifier 10, filter circuit 20 and frequency converter 30.

When three phase mains is owed the phase situation, can cause the ripple amplitude of ripple voltage on the increase of input current in the rectifier 10 and the dc bus to become big, so, to influence life of capacitors in commutator 10 and the filter circuit 20, and at present power supply is owed to detect mutually and is mostly detected in the mode of hardware circuit and judge, its hardware circuit detection mode also need take certain accommodation space and its electronic component has certain life-span except needs hardware setting cost, promptly the fault probability is also higher.

Therefore, how to provide a kind of power supply cheaply to owe the phase detection method, become one of researcher's problem to be solved.

Summary of the invention

In view of above problem, main purpose of the present invention is to provide a kind of three phase mains to owe the detection method of phase, utilize the variation that detects ripple voltage on the dc bus, to judge that whether power supply status is for owing phase, and its judgment mode determines by computed in software, to replace the hardware circuit detection mode, reach the purpose that reduces cost.

Therefore, for reaching above-mentioned purpose, disclosed three phase mains is owed the detection method of phase, includes the following step:

At first, set and owe phase testing conditions value, include: owe phase state frequency value, voltage detecting higher limit, voltage detecting lower limit and owe phase state ripple voltage value; In the time in sampling period, detect the change in voltage of dc bus, with amplitude size (being voltage swing) and the frequency values of obtaining ripple voltage on the dc bus; Owe phase state-detection condition relatively this magnitude of voltage and this frequency values according to this; And meet when owing mutually status condition when frequency values and magnitude of voltage, determine three phase mains for owing the phase state.

Wherein, in this time in sampling period, the sampled value of this magnitude of voltage is during more than or equal to the maximum of this magnitude of voltage, and this maximum of upgrading this magnitude of voltage is this sampled value; When this sampled value of this magnitude of voltage was less than or equal to the minimum value of this magnitude of voltage, this minimum value of upgrading this magnitude of voltage was this sampled value; This magnitude of voltage of this ripple voltage is the difference of this maximum and this minimum value.

Wherein, the step that obtains this frequency values includes: in this ripple voltage less than or when waiting this voltage detecting lower limit, judge whether the last attitude of this ripple voltage is this dc ripple voltage of positive half cycle; When this last attitude of this dc ripple voltage is positive half cycle, switch to a negative half period cycle count; In this ripple voltage greater than or when waiting this voltage detecting higher limit, judge whether the last attitude of this ripple voltage is this ripple voltage of negative half period; When this last attitude of this ripple voltage was negative half period, promptly finished the counting of one-period this moment, to obtain the cycle of this ripple voltage; And according to this computation of Period and obtain this frequency values of this ripple voltage.

Wherein, this cycle of this ripple voltage is also by the on average step acquisition of the counting of this one-period; This is owed the phase status condition and owes phase state frequency value and this magnitude of voltage is owed phase state ripple voltage value more than or equal to this for this frequency values is less than or equal to this.

Wherein, owing the phase status condition and be frequency values is less than or equal to and owes phase state frequency value (example, 90Hz～130Hz), and magnitude of voltage is more than or equal to the phase state of the owing ripple voltage value of setting.

Owe the detection method of phase by this three phase mains, utilize sampling and the variation that continues to detect the dc bus ripple voltage, judge in the computed in software mode whether power supply owes phase,, reach to reduce and detect the purpose that power supply is owed the phase cost to replace the detection mode of hardware circuit.

Relevant characteristics and implementation of the present invention now are described in detail as follows as most preferred embodiment in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 is the system block diagrams of the frequency converter of prior art;

Fig. 2 is the waveform schematic diagram of dc bus ripple voltage proposed by the invention;

Fig. 3 is the flow chart of steps of computation of Period proposed by the invention; And

The flow chart of steps that Fig. 4 owes to detect mutually for power supply proposed by the invention.

Wherein, description of reference numerals is as follows:

10 rectifiers

11 dc bus ripple voltages

The maximum of 11a dc bus voltage

The minimum value of 11b dc bus voltage

12 voltage detecting higher limits

13 voltage detecting lower limits

20 filter circuits

30 frequency converters

40 control circuits

50 motors

Step 100 detects the instantaneous value of dc bus voltage

Step 101 judges that dc bus voltage and setting voltage detect the relation of upper limit value and lower limit value

Is the last attitude of step 102 positive half cycle?

Step 103 switches to the negative half period cycle count

Is the last attitude of step 104 a negative half period?

Step 105 switches to positive half cycle cycle count

Step 106 cycle counting is average

Is the step 107 ripple voltage cycle more than or equal to cycle counting higher limit?

Step 108 cycle is the cycle of dc bus ripple voltage

The phase testing conditions is owed in step 200 initialization and setting

Step 201 continues to detect and the sampling dc bus voltage

Does step 202 judge that the voltage that detects exceeds present maximum?

It is sampled value that step 203 is upgraded maximum

Does step 204 judge that the voltage that detects exceeds present minimum value?

It is sampled value that step 205 is upgraded minimum value

Does the step 206 one-period time arrive?

Step 207 obtains new ripple voltage value and the beginning of next cycle time

Whether step 208 detection ripple voltage frequency values meets with magnitude of voltage is owed setting state value mutually

Step 209 decision power supply is for owing the phase state

Embodiment

In general, the frequency values of the ripple voltage on the dc bus is about 6 times supply voltage frequency values, that is to say, when the supply voltage frequency values is three-phase 60Hz, its ripple frequency value is 360Hz, and when the supply voltage frequency values was three-phase 50Hz, its ripple frequency value was 300Hz.

And when three phase mains is owed the phase situation, promptly become single phase poaer supply by three phase mains, its ripple frequency is about 2 times supply voltage frequency values, and example is when the supply voltage frequency values is single-phase 60Hz, its ripple frequency value becomes 120Hz, when the supply voltage frequency values is single-phase 50Hz, its ripple frequency value becomes 100Hz, so when owing to take place mutually by power supply, its ripple frequency value can be owed one of condition of phase as the judgement power supply along with the characteristic that changes.

Please refer to Fig. 2, waveform schematic diagram for dc bus voltage of the present invention, in the sampling time of one-period, continue to detect the voltage 11 of dc bus, so that obtain the maximum 11a and the minimum value 11b of ripple voltage, and then obtain the size of ripple voltage, and the voltage detecting higher limit 12 and voltage detecting lower limit 13 set, in order to the cycle of counting ripple voltage, to calculate and to obtain the frequency values of ripple voltage.

Please refer to Fig. 3, be the flow chart of steps of computation of Period of the present invention, at first, detect the instantaneous value (step 100) of dc bus voltage; Next, judge itself and the relation (step 101) of the voltage detecting upper limit value and lower limit value of setting, include: be less than or equal to the voltage detecting lower limit, more than or equal to the voltage detecting higher limit and between voltage detecting higher limit and voltage detecting lower limit three kinds of relations.

When if the dc bus voltage value is less than or equal to the voltage detecting lower limit of setting, judge then whether last attitude is the ripple voltage (step 102) of positive half cycle, if when confirming that last attitude is the ripple voltage of positive half cycle, then switch to negative half period cycle count (step 103), and get back to step 100.

If the dc bus voltage value is during more than or equal to the voltage detecting higher limit set, judge then whether last attitude is the ripple voltage (step 104) of negative half period, if when confirming that last attitude is negative half period, then switch to positive half cycle cycle count (step 105), to calculate the cycle of ripple voltage; If when last attitude is not negative half period, then get back to step 100.

If ripple voltage between between the voltage detecting lower limit of the voltage detecting higher limit of setting and setting the time, judges further then whether the cycle of ripple voltage counts higher limit (step 107) more than or equal to a cycle; If the cycle of ripple voltage, then a cycle was the cycle of ripple voltage when counting higher limit more than or equal to a cycle.

After step 105 and step 108, all the cycle counting value of averaging is calculated (step 106), detect error to reduce, next, get back to step 100, detect and the cycle of calculating ripple voltage with lasting.

So just can obtain the cycle of ripple voltage on the dc bus, and cycle and frequency reciprocal relation each other, promptly the cycle=(1/ frequency) or frequency=(1/ cycle), therefore, also can obtain the frequency values of ripple voltage.

Please refer to Fig. 4, the flow chart of steps of owing to detect mutually for power supply of the present invention, at first, initialization and setting power supply are owed each set point (step 200) of phase state-detection, and the set point content includes: voltage detecting higher limit, voltage detecting lower limit, owe phase state frequency value and owe phase state ripple voltage value, and dc bus voltage maximum and minimum value be set at the instantaneous value of dc bus voltage, and owe the supply frequency value that phase state frequency value is a twice (example, 90Hz～130Hz).

Next, continue to detect and sampling dc bus voltage (step 201), and whether the comparative voltage sampled value is more than or equal to present maximum (step 202); If sampled value is during more than or equal to present maximum, then upgrading maximum is sampled value (step 203); If sampled value is not more than or equal to maximum, then maximum remains unchanged.

Whether the comparative voltage sampled value is less than or equal to present minimum value (step 204); If when sampled value was less than or equal to present minimum value, then upgrading present minimum value was sampled value (step 205); If sampled value is not less than or equal to present minimum value, then present minimum value remains unchanged.

Next, after step 203, step 204 and step 205, judge all whether the sampling time of one-period arrives (step 206), and promptly whether the one-period time arrives; If during the sampling time of no show one-period, then get back to step 201, to continue the instantaneous value of sampling dc bus voltage.

If the sampling time of one-period is when arriving, promptly represent the time of next cycle to begin, the maximum of dc bus voltage is deducted minimum value, be the ripple voltage value of the dc bus voltage that one-period samples, and the instantaneous value of dc bus voltage is set at the initial value of maximum and minimum value, with reference value (step 207) as following one-period.

Then, whether the magnitude of voltage of judging the ripple voltage that detects is more than or equal to the phase state of the owing ripple voltage value of setting, and what whether the frequency values of the ripple voltage that detects was less than or equal to setting owes phase state frequency value (example, the supply frequency 90Hz of twice～130Hz) (step 208), if all meet the condition of owing to judge mutually, promptly determine present power supply status for owing phase situation (step 209), and the result is offered phase failure protection circuit (not shown), with protection equipment; If do not meet when owing the phase status condition, then get back to step 201.

In addition, cycle count and ripple voltage can adopt the mean value calculation mode, with the minimizing error amount, and by changing the phase state of the owing ripple voltage value of setting, can adjust and detect the sensitivity that power supply is owed phase, to reach the purpose of equipment protection and elasticity utilization.

Owe the detection method of phase by this three phase mains, by the ripple voltage frequency values on sampling and the lasting detection dc bus and the variation of magnitude of voltage (amplitude), and after calculating, judge whether power supply owes phase, to replace the hardware circuit detection mode, detect the purpose that power supply is owed the phase cost to reach to reduce.

Though the present invention discloses as above with aforesaid preferred embodiment; right its is not in order to limit the present invention; any those skilled in the art; without departing from the spirit and scope of the present invention; when can doing a little change and retouching, therefore scope of patent protection of the present invention must be looked being as the criterion that this specification appending claims defined.

Claims

1. a three phase mains is owed the detection method of phase, sets one and owes phase state-detection condition, it is characterized in that including:

In the time in sampling period, detect the change in voltage of a direct current bus, with magnitude of voltage and the frequency values of obtaining the ripple voltage on this dc bus;

The described phase state-detection condition of owing is owed phase state frequency value and this magnitude of voltage and is owed phase state ripple voltage value more than or equal to this for this frequency values is less than or equal to, and owes phase state-detection condition relatively this magnitude of voltage and this frequency values according to this; And

When this magnitude of voltage and this frequency values meet this and owe mutually the state-detection condition, determine this three phase mains for owing the phase state.

2. detection method according to claim 1, wherein, this is owed the phase testing conditions and includes a voltage detecting higher limit, a voltage detecting lower limit and and owe mutually state frequency value and and owe phase state ripple voltage value.

3. detection method according to claim 2, wherein, in this time in sampling period, the sampled value of this magnitude of voltage is during more than or equal to the maximum of this magnitude of voltage, and this maximum of upgrading this magnitude of voltage is a sampled value.

4. detection method according to claim 3, wherein, in this time in sampling period, this sampled value of this magnitude of voltage is during more than or equal to the maximum of this magnitude of voltage, and this minimum value of upgrading this magnitude of voltage is this sampled value.

5. detection method according to claim 4, wherein, this magnitude of voltage of this ripple voltage is the difference of this maximum and this minimum value.

6. detection method as claimed in claim 2, wherein, the step that obtains this frequency values includes:

When this ripple voltage is less than or equal to this voltage detecting lower limit, judge whether the last attitude of this ripple voltage is this dc ripple voltage of positive half cycle;

When this last attitude of this dc ripple voltage is positive half cycle, switch to a negative half period cycle count;

During more than or equal to this voltage detecting higher limit, judge whether the last attitude of this ripple voltage is this ripple voltage of negative half period in this ripple voltage;

When this last attitude of this ripple voltage was negative half period, promptly finished the counting of one-period this moment, to obtain the cycle of this ripple voltage; And

According to this computation of Period and obtain this frequency values of this ripple voltage.

7. detection method as claimed in claim 6, wherein, this cycle of this ripple voltage is also by the on average step acquisition of the counting of this one-period.

8. detection method as claimed in claim 2, wherein, this owes phase state frequency value is 90Hz～130Hz.