Diagnosis for expected life of emergency power apparatus

• US 20060152224A1
• Filed: 04/22/2003
• Published: 07/13/2006
• Est. Priority Date: 04/23/2003
• Status: Active Grant

• Current Assignee: Powertron Engineering Co., Ltd.
• Original Assignee: Powertron Engineering Co., Ltd.
• Inventors: Kim, Gi-Taek, Kim, Deuk-Soo, Kim, Rae-Young
• Granted Patent: US 7,567,085 B2
• Time in Patent Office: Days
• US Class Current: 324/430
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health

Abstract

This invention measures the exact value of impedance voltage (Vis) from AC actual waveform (V_SM) which includes ripple noise voltage, and suggests the inventive circuits and softwares capable of acquiring the effective resistance of battery internal impedance and the operational algorithm of the diagnosis for the expected life of battery string. In accordance with a series of functional operations and the execution of the program in MPU, this diagnostic system can find the cause of aging progress in advance and settle by unmanned monitoring the healthiness of emergency power system always in real time at remote site.

Claims

1. A battery diagnostic system to be used to monitor the aging status of each of multiple rechargeable battery cells by measuring the characteristic data of a large number of serially connected batteries, the arrangement comprising:

a group of relay circuits (4) is connected with each cell of the batteries;

the relay contacts in the said group of relaying circuits (4) are connected with the (+) and (−

) of every battery cell through 4-terminal circuit network;

the constant current source (5) being controlled by main controller unit (MCU, 11) is connected with the said group of the relaying circuits (4);

the input/output equipments such as LCD and/or KEYPAD are connected with the MCU (11);

the total system being controlled and managed by MPU (1) in the said MCU (11),

and wherein the operation comprising;

the select control signal generated by the MPU (1) activates the corresponding relay which connects the battery cell to be measured in accordance with the measuring sequence with the input port of the MCU;

the constant current source (5) being started by the clock signal (CLK) generated by the MPU (1) and the constant current (Is) generated by the constant current source (5) being supplied to the battery through the said group of relaying circuits (4),

the characteristic data such as battery voltage (V), impedance voltage (Vis), AC constant current (Is), temperature (T), Gravity (G) being amplified by the automatic scaling circuit (7), and digitized by the A/D converter (6) and then stored in the memory device in the MPU (1);

the said MPU (1) stopping the said constant current source (5), the internal impedance of a battery cell being calculated by the disclosed impedance calculation program;

the battery aging status being determined by the program in the MPU (1) on the basis of the characteristic data and battery cell internal impedance;

the said characteristic data, the battery internal impedance and a battery status history data being recorded in the memory (2);

the said series of all operations and all steps, of measuring, computing and storing data being repeated and the said diagnosis data of the battery strings being transmitted to the PC or host via RS232, RS422, RS485 or CDMA if necessary.

3. The system according to claim 1 further comprising the mobile battery diagnosis apparatus without the said group of relaying circuits (4), the system comprising:

without the group of relaying circuits (4);

the input of the said MCU (11) being connected to the (+) and (−

) of the battery cell to be measured through the 4-terminal circuit network manually;

the measurement on the battery cell being initialized by external signal or internal signal from MCU (11);

the AC constant current (Is) from the constant current source (5) initiated by the CLK or ON/OFF signal from MPU (1) being applied to the battery cell through the 4-terminal circuit network;

the characteristic data such as battery cell voltage (V), impedance voltage (Vis), AC constant current (Is), temperature (T) of the battery cell under measurement being amplified by the automatic scaling circuit (7);

the said characteristic data being converted by A/D converter (6) and stored in the MPU (1);

the internal impedance of the battery cell being calculated by the disclosed impedance computation program;

the battery aging status being determined by the program in the MPU (1) on the basis of the characteristic data and the said internal impedance of the battery cells;

the said characteristic data, the said internal impedance and the said aging status historical data being recorded in the memory (2), the said data being displayed on the output device such as LCD;

the said series of all operations and all steps, of measuring, computing and storing data for the other cells being processed repeatedly;

the stored data in the said MCU (11) being transmitted to lap top computer, server or host computer through USB, RS232, RS422 and RS485 if necessary.

10. The method according to the claim 1 wherein:

the software installed in the main process unit (MPU) of the said MCU (11) composed of main program and timer interrupt program;

the timer interrupt program being executed periodically with the predetermined time intervals;

the group of relaying circuits being operated by the timer interrupt program, the measured data being acquired as required by the timer interrupt program, the constant current source (5) being activated by the timer interrupt program by a required condition;

the internal impedance voltage waveform of the battery as well as the constant current waveform being acquired in the timer interrupt program by a required condition;

the battery impedance computation algorithm being executed in the timer interrupt program by a required condition;

the wave forms of the DC voltage, DC current and AC voltage being acquired in the timer interrupt program by a required condition;

the measured data acquired and the impedance data computed by the impedance computing algorithm being stored in the memory;

returning to the main program after the said timer interrupt program being executed, the program does not return to the main program when acquiring the battery internal impedance voltage wave form under the said condition and continues to execute the said timer interrupt program for a fixed time;

the data related to the quality of the emergency power system being acquired without any loss while the internal impedance voltage is being acquired.

11. The system according to the claim 1 wherein:

the select control signal to control the relay connections to the battery cells being composed of 6 bit signal;

one group among the up to four groups of relaying circuits being selected by 2 bit select signal;

the rest 4 bits being inputted to the input terminals (DO-D3) of the decoder circuit (MUX) and finally selecting one of up to 16 relay assemblies among the said group of relaying circuits selected by the said 2 bit select signal;

a group of relaying circuits (4) being identical and suitable for multi-layer application.

12. The system according to the claim 1 wherein:

the clock signal (CLK) driven from the clock of the MPU (1) being connected to the constant current source (5);

the frequency of the AC constant current (Is) of the said constant current source (5) being driven from the said clock signal (CLK);

and the periods of AC impedance voltage (Vis) and AC constant current (Is) by the above implementation can be easily acquired.

13. The system according to the claim 1 wherein:

the constant current source (5) in order to settle the AC output current at the steady state quickly without overshoot being composed as;

the clock signal (CLK) driven from MPU (1) clock being supplied to the said constant current source (5);

the AC output current feedback signal (If) being connected to operational amplifier (31);

the difference (−

) between the said output current feedback value (If) and the current set value (43) being applied to the amplitude control terminal (10) of the sinusoidal waveform generation circuit (33);

the output of the said sinusoidal waveform generation circuit (33) being differentially added to the feedback value (If) of output current through the instantaneous value addition circuit (34) to improve the transient response;

the said differentially added value being applied to No. 1 B class amplifier (35);

the clock signal (CLK) being integrated to produce the slowly uprising soft start signal (SS) through the soft start circuit (39);

the said soft start signal (SS) being connected to the output of the said operational amplifier (31) with the highest priority.

14. The system according to the claim 1 wherein the constant current source being composed as:

the AC sinusoidal waveform being generated by the disclosed integrated circuits (IC) or sinusoidal waveform generation circuits;

the said AC sinusoidal waveform generation circuit (33) being differentially added to the feedback value (I_f) through the instantaneous value addition circuit (34);

the output of the instantaneous value addition circuit (34) being amplified by the No. 1 B class amplifier (35);

wherein the No. 1 B class amplifier circuit (35) comprising;

the output of the operational amplifier (U3) being connected to the base of NPN transistor (Q1) and the base of PNP transistor (Q2) respectively;

the collectors of the said NPN transistor (Q1) and PNP transistor (Q2) being connected to (+) and (−

) DC power source respectively;

the emitters of the said NPN transistor (Q1) and PNP transistor (Q2) being connected to the inverting (−

) input of the said operational amplifier (U3) and one terminal of the primary winding of the signal transformer (T2) in common;

the constant current (Is) being generated at the secondary winding of the said signal transformer (T2) and being isolated electrically.

15. The system according to the claim 1 wherein the constant current source being composed as:

the AC sinusoidal waveform being generated through the disclosed integrated circuits (IC) or the disclosed sinusoidal waveform generation circuits;

the AC sinusoidal waveform generation circuit (33) being differentially added to the feedback value (If) through the instantaneous value addition circuit (34);

the output of the said instantaneous value addition circuit (34) being amplified by the No. 1 B class amplifier (35);

the output of the said No. 1 B class amplifier (35) being connected to the primary winding of the signal transformer (T2);

two secondary windings of the said signal transformer (T2) being arranged to generate two sinusoidal signals with 180 degree phase difference;

the said two sinusoidal signals being amplified by the No. 2 B class amplifier (37);

the output of the said No. 2 B class amplifier (37) being isolated by the isolation circuit (38), then being used as a constant current source for the measurement of battery internal impedance;

wherein the said No. 1 B class amplifier (35) comprising;

the output of the operational amplifier (U3) being connected to both the base of NPN transistor (Q1) and the base of PNP transistor (Q2);

the collectors of the said NPN transistor (Q1) and PNP transistor (Q2) being connected to (+) and (−

) DC power source respectively;

the emitters of the said NPN transistor (Q1) and the said PNP transistor (Q2) being connected to the inverting terminal (−

) of the said operational amplifier (U3) and one terminal of the primary winding of the signal transformer (T2) in common;

the other terminal of the primary winding of the said signal transformer (T2) being grounded;

wherein the said No. 2 B class amplifier (37) comprising;

the center tap of the primary winding of the output transformer (TM1) being connected to the (+) DC power source;

the starting point and ending point of the primary winding of the said output transformer (TM1) being connected to the collectors/drains of the transistor Q3 and Q4 respectively;

the constant current (Is) being generated by the output of the No. 2 B class amplifier (37) and isolated in the said output transformer (TM1).

16. The system according to the claim 1 wherein the automatic scaling circuit (7) in the main controller unit (11) being composed as:

a measurement signal such as AC actual voltage (VsM) being commonly connected with the inputs of several operational amplifiers (50) having different amplifying gains;

the outputs of the said several operational amplifiers (50) being connected to the input of the signal selector (51) such as analog switch;

the common output of the said signal selector (51) being connected to the input terminal of the A/D converter (6);

the operational amplifier with proper amplifying gain being selected among the said operational amplifiers (50);

the operational amplifier having maximum output without saturation being selected by checking the output of the amplifier with the highest gain first, then the amplifier with the next highest gain until finding the amplifier without saturation.

17. The system according to the claim 1 wherein the impedance computation program includes the processes:

the AC voltage (Vis) and constant current (Is) being applied to the zero crossing detector circuit respectively, and zero crossing signals (ZCV1, ZCV2, ZCI1, ZCI2) being generated by the zero crossing detector circuits;

the 1^st voltage counter data (t_v1) the 2^nd voltage counter data (t_v2), the 1^st current counter data (t_i1) and the 2^nd current counter data (t_i2) acquired at the instants of the respective zero crossing signals (ZCV1, ZCV2, ZCI1, ZCI2) being used to find the period Tv=tv2−

tv1 of AC voltage (Vis) and the period Ti=ti2−

ti1 of AC constant current (Is);

the phase difference between the AC voltage (Vis) and the AC constant current (Is) being computed from the difference between the said 1^st voltage counter data (t_v1) and the said 1^st current counter data (t_v1);

the average values of the AC voltage (Vis) and the AC constant current (Is) during the said period (Tv, Ti) being computed respectively.

21. The system according to the claim 1 wherein remote communication network comprising:

the online network such as wireless communication or internet with communication port installed on measurement/diagnostic system;

in case of employing internet, one fixed IP attached to a host can control/monitor the operations of more than 1,000 sites on line by controlling N emergency power supply systems on each site;

the operational status of multiple emergency power systems and their battery aging status being monitored by a single remote computer.

2. A measurement/diagnostic system to be used to evaluate the aging status of each of multiple rechargeable battery cells and to monitor the power quality of the emergency power system (18) such as UPS and telecom power supply, the arrangement comprising:

an AC sensor circuit (15) coupled to measure the AC voltage and AC current of the emergency power supply system (18);

a DC sensor circuit (14) coupled to measure the DC voltage and DC current of the emergency power supply system (18);

the relay contacts in a group of relaying circuits (4) connected with the (+) and (−

) terminals of each battery string through 4-terminal circuit network;

the constant current source (5) coupled with the group of relaying circuits (4);

the main controller unit (11) comprising MPU (1), pre-amplifier (16) to amplify the input signals to the optimum, automatic scaling circuit (7), A/D converter (6) and the communication port such as RS232, RS485, CDMA and LAN;

the input/output devices such as LCD and/or KEYPAD connected with the main controller unit (11),

and wherein the operation comprising;

the total system being controlled and managed by the MPU (1) in the said MCU (11);

the select control signal from the MPU (1) activating the selected relay and the constant current source (5) by the clock signals generated by the MPU (1), and the activated AC constant current (Is) from the said constant current source (5) being applied to the selected battery cell through the said group of relaying circuits (4);

the characteristic data such as voltage (V), impedance voltage (Vis), AC current (Is), temperature (t), gravity (G) being collected through the said group of relaying circuits (4), and the diagnosis of the aging status of the selected battery cell being processed by the program installed in the MPU (1) on the basis of the collected data;

the charging/discharging voltages (DCV) and the charging/discharging currents (DCA) of the battery strings and the AC voltage and AC current of the emergency power supply system (18) being collected and recorded at the same time;

AC voltage and current waveform being collected at the same time;

the internal battery impedance being computed by the impedance computation program and the measured and computed data being recorded;

the said series of all operations and all steps, of measuring, computing and storing data being executed repeatedly;

the stored data being transmitted to the host computer through the said communication ports (8) at the predetermined time;

when the values of the said measured data and the said computed data beyond the preset values, the failure alarm and event time being set;

and data being transmitted to the remote or host computer via the communication ports (8) along with failure time.

4. On measuring the internal impedance to evaluate the aging status of batteries, capacitors or edematous part, the measuring method for the true RMS value of the small signals to get the impedance voltage (Vis) comprising:

the frequency of AC constant current (Is) supplied to the objects to measure the internal impedance being set as integer times the frequency o3S of the commercial power source;

the frequency of the impedance voltage (Vis) induced by AC constant current (Is) being the same frequency of the said AC constant current (Is);

the disclosed noise rejection circuit which has narrow band characteristics centered at the same frequency of the said AC constant current (Is) being used if necessary;

the noise ripple voltage (V_RP,FLT) and AC actual voltage (V_SM) being acquired;

by mutual addition and subtraction of all the frequencies of all the harmonics belonging to the said AC actual voltage (V_SM), producing the 1st greatest common measure (GCM) among the said resultant values of mutual addition and subtraction;

by mutual addition and subtraction of all the frequencies of all the harmonics belonging to the said noise ripple voltage (V_RP,FLT), produce the 2nd GCM among the said resultant values of mutual addition and subtraction;

produce the 3rd GCM between the said 1St GCM and the said 2nd GCM;

the integration interval (T_D) for the computation of the RMS values of the said AC actual voltage (V_SM) and the noise ripple voltage (V_RP,FLT) being set to the said 3rd GCM or its common multiple;

acquiring the RMS values by integrating the said AC actual voltage (V_SM) and harmonic ripple voltage (V_RP,FLT) for the said integration interval (T_D).

5. According to the claim 4, the method making the computation time of the RMS impedance voltage reduced wherein:

the harmonic portions of the noise ripple voltage (V_RP,FLT) generated being composed of the odd and even multiples of the commercial power frequency ω

S;

the frequency of the AC constant current (Is) being set to a certain harmonic frequency among the harmonics of the said noise ripple voltage (V_RP,FLT);

the integration interval (T_D) necessary to compute RMS value of impedance voltage being set to one cycle of the said commercial power frequency ω

S making the computation time of the RMS impedance voltage reduced.

6. According to the claim 4, the method making the computation time of the RMS impedance voltage reduced wherein:

the harmonics of the noise ripple voltage (V_RP,FLT) composed of the frequencies belonging to only one party of the even or odd multiples of the commercial power source frequency ω

S;

the frequency of the AC constant current (Is) being set to one of odd or even harmonics of the said noise ripple voltage (V_RP,FLT);

the integration interval (T_D) necessary to compute RMS value of impedance voltage being set to a half cycle of the said commercial power frequency ω

S making the computation time of the RMS impedance voltage reduced.

7. The method according to the claim 4 wherein:

the frequency of AC constant current (Is) being set to the mean value of 2 adjacent harmonic frequencies of the said noise ripple voltage (V_RP,FLT);

the integration interval (T_D) necessary to compute the RMS value being set to the 3rd greatest common measure or its integer multiple making the computation time of the RMS impedance voltage reduced.

8. The method according to the claim 4 wherein:

the computation of the RMS impedance voltage being executed by the application program in the MCU;

in the section P1, the noise ripple voltage (V_RP,FLT) being acquired during the time of the said integration interval (T_D);

in the section P2, the AC actual voltage (V_SM) which is the sum of the said noise ripple voltage (V_RP,FLT) and the said impedance voltage (Vis) being acquired during the time of the said integration interval (T_D);

the squared value of the RMS value (V_RP,RMS) of noise ripple voltage for the said integration interval (T_D) being computed from the acquired noise ripple voltage (V_RP,RMS) in the said section P1;

the squared value of the RMS value (V_SM,RMS) of impedance voltage for the said integration interval (T_D) is computed from the acquired AC actual wave form (V_SM) in the said section P2;

the square root value of the difference of these two squared values being computed.

9. The method according to the claim 4 wherein:

the computation of the RMS impedance voltage being executed by the application program in the MCU;

in the section P1, the noise ripple voltage waveform (V_RP,FLT), without the AC constant current (Is), being acquired for the integration interval (T_D);

in the section P2, the AC actual voltage waveform (V_SM), with the AC constant current (Is), being acquired for the integration interval (T_D);

in the said section PI, the squared value of the said noise ripple voltage (V_RP,FLT) being obtained by squaring the difference between the instantaneous values of said noise ripple voltage at the n^th sampling time (T_n,RP) and the base value (Vo)

(V_RP,FLT−

V_O)²_n;

then, being summed with the accumulated value up to (n−

1)^th sampling time stored in the appointed memory (M1) and given by the equation;

$\underset{i=1}{\overset{n-1}{\sum <br><br>}}<br><br>{\left(V_{\mathrm{RP},\mathrm{FLT}}-V_O\right)}_i^2$

then, the summation being stored in the said memory (M1);

the said computing operation being processed N times from the first sampling time (T_1,RP) to the n^th sampling time (T_n,RP);

in the section (P2), the instantaneous values of the said AC actual voltage (V_SM) being sampled at the n^th acquisition time and subtracted the base value (Vo), and being squared;

the sum of the n^th squared value with the accumulated value of up to (n−

1)^th sampling given by the equation

$\underset{i=1}{\overset{n-1}{\sum <br><br>}}<br><br>{\left(V_{\mathrm{SM},\mathrm{FLT}}-V_O\right)}_i^2$

being stored in the appointed memory (M2);

the said computing and storing process being repeated N times from the first acquired time (T_1,SM) to the n^th acquired time (T_n,SM);

the value stored in the said memory (M1) being subtracted with the value stored in the said memory (M2);

the difference being divided by the said integration interval (T_D) and being square rooted to compute the RMS voltage.

18. A system configuration to monitor the operations of multiple emergency power systems (18) and the aging status of battery cells, with the multiple measurement/diagnostic systems, the arrangement comprising:

the measurement/diagnostic system (164-a, 164-b, - - - , 164-n) with identical structure being mutually connected through the internal communication ports (163);

one measurement/diagnostic system being designated as a master and the others as slaves, and the master system (164) can communicate with every slave systems (164-a, 164-b, - - - , 164-n);

the said slave measurement/diagnostic system (164-a, 164-b, - - - , 164-n) being connected with the local supervisory systems (169-a, 169-b, - - - , 169-n) through serial ports;

the main measurement/diagnostic system (164) can be configured to have a wireless communication port for wireless remote communication;

the remote network communication can be done through the local monitoring system (169) connected with main measurement/diagnostic system (164);

all the measurement/diagnostic system (164,164-a, 164-b, - - - , 164-n) have serial communication ports for the connection with any remote control apparatus or console apparatus including the local monitoring systems;

the local monitoring system (169) connected with the main measurement/diagnostic system is configured to be able to adjust parameters and to retrieve the data of the slave systems through the communication port.

19. The system according to the claim 18 wherein:

an emergency power system and a slave measurement/diagnostic system with the same communication protocol being replaced to a slave measurement/diagnostic system;

the serial communication ports of the emergency power systems being connected to the main measurement/diagnostic system;

the said emergency power systems can be controlled and monitored by remote and local system through the communication network provided.

20. The method according to the claim 18 wherein instead of the said slave measurement/diagnostic system, a measurement/diagostic unit being configured as having only the circuits comprising:

the main controller unit (11) with simple function,

the constant current source (5),

and the group of relaying circuit (4), and one serial communication port;

and the said measurement/diagnostic units (1,2, 3, - - - , N) can be installed adjacent to the strings of the several batteries;

the said main measurement/diagnostic system (164) being mutually connected with the said measurement/diagnostic units (1, 2, 3, - - - , N) through simple serial communication port such as RS485;

any parameters or stored data of the said measurement/diagnostic units being adjusted or retrieved through the local system (169) like PC;

the said main measurement/diagnostic system (164), if necessary, being connected to wireless communication network or remote network for the access by remote and local monitoring system.